Wear-time compliance with a dual-accelerometer system for capturing 24-h behavioural profiles in children and adults.

Duncan, S. Stewart, T. Mackay, L. Neville, J. Narayanan, A. Walker, C. Berry, S. Morton, S.

Int. J. Environ. Res. Public Health (2018)

Abstract: To advance the field of time-use epidemiology, a tool capable of monitoring 24 h movement behaviours including sleep, physical activity, and sedentary behaviour is needed. This study explores compliance with a novel dual-accelerometer system for capturing 24 h movement patterns in two free-living sa... To advance the field of time-use epidemiology, a tool capable of monitoring 24 h movement behaviours including sleep, physical activity, and sedentary behaviour is needed. This study explores compliance with a novel dual-accelerometer system for capturing 24 h movement patterns in two free-living samples of children and adults. A total of 103 children aged 8 years and 83 adults aged 20-60 years were recruited. Using a combination of medical dressing and purpose-built foam pouches, participants were fitted with two Axivity AX3 accelerometers—one to the thigh and the other to the lower back—for seven 24 h periods. AX3 accelerometers contain an inbuilt skin temperature sensor that facilitates wear time estimation. The median (IQR) wear time in children was 160 (67) h and 165 (79) h (out of a maximum of 168 h) for back and thigh placement, respectively. Wear time was significantly higher and less variable in adults, with a median (IQR) for back and thigh placement of 168 (1) and 168 (0) h. A greater proportion of adults (71.6%) achieved the maximum number of complete days when compared to children (41.7%). We conclude that a dual-accelerometer protocol using skin attachment methods holds considerable promise for monitoring 24-h movement behaviours in both children and adults.

A Dual-Accelerometer System for Classifying Physical Activity in Children and Adults

Stewart, T., Narayanan, A., Hedayatrad, L., Neville, J., Mackay, L. and Duncan, S.

Medicine and science in sports and exercise (2018).

Abstract: Accurately monitoring 24-hour movement behaviours is a vital step for progressing the time-use epidemiology field. Past accelerometer-based measurement protocols are either hindered by lack of wear time compliance, or the inability to accurately discern activities and postures. Recent work has indic... Accurately monitoring 24-hour movement behaviours is a vital step for progressing the time-use epidemiology field. Past accelerometer-based measurement protocols are either hindered by lack of wear time compliance, or the inability to accurately discern activities and postures. Recent work has indicated that skin-attached dual-accelerometers exhibit excellent 24-hour uninterrupted wear time compliance. This study extends this work by validating this system for classifying various physical activities and sedentary behaviours in children and adults.

Comparison of tri-axial accelerometers step-count accuracy in slow walking conditions

Feng, Y., Wong, C.K., Janeja, V., Kuber, R. and Mentis, H.M.

Gait & Posture 53 (2017)

Abstract: Accelerometers have shown great promise and popularity for monitoring gait. However, the accuracy of accelerometers for gait analysis in slow walking conditions is largely unknown. In this study, we compared the accuracy of three accelerometers recommended for gait analysis – Axivity AX3, APDM Opa... Accelerometers have shown great promise and popularity for monitoring gait. However, the accuracy of accelerometers for gait analysis in slow walking conditions is largely unknown. In this study, we compared the accuracy of three accelerometers recommended for gait analysis – Axivity AX3, APDM Opal, and the Actigraph wGT3X-BT, by holding the step-count algorithm constant. We evaluated device accuracy in four minutes of treadmill walking at the speeds of 0.9 m/s, 1.1 m/s, and 1.3 m/s. We constructed a symbolization of the gait data to count the steps using Piecewise Aggregate Approximation and compared the estimated step counts with observer counted steps from video recordings. Our results highlight the variation between the performance of devices – the Axivity AX3 provides more accurate step counts than the other two devices. In this, we provide evidence for future scientific teams to make decisions on selecting accelerometers which can more accurately measure steps taken at slower walking speeds, and suggest ways to improve the design of algorithms and accelerometers.

A model of free-living gait: A factor analysis in Parkinson's disease

Morris, R., Hickey, A., Del Din, S., Godfrey, A., Lord, S. and Rochester, L.

Gait & Posture 52 (2017)

Abstract: Introduction: Gait is a marker of global health, cognition and falls risk. Gait is complex, comprised of multiple characteristics sensitive to survival, age and pathology. Due to covariance amongst characteristics, conceptual gait models have been established to reduce redundancy and aid interpretat... Introduction: Gait is a marker of global health, cognition and falls risk. Gait is complex, comprised of multiple characteristics sensitive to survival, age and pathology. Due to covariance amongst characteristics, conceptual gait models have been established to reduce redundancy and aid interpretation. Previous models have been derived from laboratory gait assessments which are costly in equipment and time. Body-worn monitors (BWM) allow for free-living, low-cost and continuous gait measurement and produce similar covariant gait characteristics. A BWM gait model from both controlled and free-living measurement has not yet been established, limiting utility. Methods: 103 control and 67 PD participants completed a controlled laboratory assessment; walking for two minutes around a circuit wearing a BWM. 89 control and 58 PD participants were assessed in free-living, completing normal activities for 7 days wearing a BWM. Fourteen gait characteristics were derived from the BWM, selected according to a previous model. Principle component analysis derived factor loadings of gait characteristics. Results: Four gait domains were derived for both groups and conditions; pace, rhythm, variability and asymmetry. Domains totalled 84.84% and 88.43% of variance for controlled and 90.00% and 93.03% of variance in free-living environments for control and PD participants respectively. Gait characteristic loading was unambiguous for all characteristics apart from gait variability which demonstrated cross-loading for both groups and environments. The model was highly congruent with the original model. Conclusions: The conceptual gait models remained stable using a BWM in controlled and free-living environments. The model became more discrete supporting utility of the gait model for free-living gait.

Recognising complex activities with histograms of relative tracklets

Stein, S. and McKenna, S.J.

Computer Vision and Image Understanding 154 (2017)

Abstract: One approach to the recognition of complex human activities is to use feature descriptors that encode visual interactions by describing properties of local visual features with respect to trajectories of tracked objects. We explore an example of such an approach in which dense tracklets are describe... One approach to the recognition of complex human activities is to use feature descriptors that encode visual interactions by describing properties of local visual features with respect to trajectories of tracked objects. We explore an example of such an approach in which dense tracklets are described relative to multiple reference trajectories, providing a rich representation of complex interactions between objects of which only a subset can be tracked. Specifically, we report experiments in which reference trajectories are provided by tracking inertial sensors in a food preparation scenario. Additionally, we provide baseline results for HOG, HOF and MBH, and combine these features with others for multi-modal recognition. The proposed histograms of relative tracklets (RETLETS) showed better activity recognition performance than dense tracklets, HOG, HOF, MBH, or their combination. Our comparative evaluation of features from accelerometers and video highlighted a performance gap between visual and accelerometer-based motion features and showed a substantial performance gain when combining features from these sensor modalities. A considerable further performance gain was observed in combination with RETLETS and reference tracklet features.

Large scale population assessment of physical activity using wrist worn accelerometers: The UK Biobank Study

Doherty A, Jackson D, Hammerla N, Plötz T, Olivier P, Granat MH, White T, van Hees VT, Trenell MI, Owen CG, Preece SJ.

PloS one (2017)

Abstract: Background: Physical activity has not been objectively measured in prospective cohorts with sufficiently large numbers to reliably detect associations with multiple health outcomes. Technological advances now make this possible. We describe the methods used to collect and analyse accelerometer measu... Background: Physical activity has not been objectively measured in prospective cohorts with sufficiently large numbers to reliably detect associations with multiple health outcomes. Technological advances now make this possible. We describe the methods used to collect and analyse accelerometer measured physical activity in over 100,000 participants of the UK Biobank study, and report variation by age, sex, day, time of day, and season. Methods: Participants were approached by email to wear a wrist-worn accelerometer for seven days that was posted to them. Physical activity information was extracted from 100Hz raw triaxial acceleration data after calibration, removal of gravity and sensor noise, and identification of wear / non-wear episodes. We report age- and sex-specific wear-time compliance and accelerometer measured physical activity, overall and by hour-of-day, week-weekend day and season. Results: 103,712 datasets were received (44.8% response), with a median wear-time of 6.9 days (IQR:6.5–7.0). 96,600 participants (93.3%) provided valid data for physical activity analyses. Vector magnitude, a proxy for overall physical activity, was 7.5% (2.35mg) lower per decade of age (Cohen’s d = 0.9). Women had a higher vector magnitude than men, apart from those aged 45-54yrs. There were major differences in vector magnitude by time of day (d = 0.66). Vector magnitude differences between week and weekend days (d = 0.12 for men, d = 0.09 for women) and between seasons (d = 0.27 for men, d = 0.15 for women) were small. Conclusions: It is feasible to collect and analyse objective physical activity data in large studies. The summary measure of overall physical activity is lower in older participants and age-related differences in activity are most prominent in the afternoon and evening. This work lays the foundation for studies of physical activity and its health consequences. Our summary variables are part of the UK Biobank dataset and can be used by researchers as exposures, confounding factors or outcome variables in future analyses.

Measuring Children’s physical activity: compliance using skin-taped accelerometers

Schneller MB, Bentsen P, Nielsen G, Brond JC, Ried-Larsen M, Mygind E.

Medicine & Science in Sports & Exercise (2017)

Abstract: Introduction: Accelerometer-based physical activity monitoring has become the method of choice in many large-scale physical activity (PA) studies. However, there is an ongoing debate regarding the placement of the device, the determination of device wear time, and how to solve a lack of participant ... Introduction: Accelerometer-based physical activity monitoring has become the method of choice in many large-scale physical activity (PA) studies. However, there is an ongoing debate regarding the placement of the device, the determination of device wear time, and how to solve a lack of participant compliance. The aim of this study was to assess the compliance of Axivity AX3 accelerometers taped directly to the skin of 9-13-year-old children. Methods: Children in 46 school classes (53.4% girls, age 11.0±1.0 years, BMI 17.7±2.8 kg*m-1 ) across Denmark wore two Axivity AX3 accelerometers, one taped on the thigh (n=903) and one on the lower back (n= 856), for up to ten consecutive days. Participants were instructed not to reattach an accelerometer should it fall off. Simple and multiple linear regression were used to determine associations between accelerometer wear time and age, sex, BMI percentiles, and PA level. Results: Over 65% had >7 days of uninterrupted, 24h wear time for the thigh location, and 59.5% for the lower back location. From multiple linear regressions, PA levels showed the strongest association with lower wear time (thigh: β=-.231, R2 =.066; lower back: β=-.454, R2 =.126). In addition, being a boy, being older (only for lower back), and having higher BMI percentile were associated with lower wear time. Conclusion: Using skin-taped Axivity accelerometers, we obtained seven days of uninterrupted accelerometer data with 24h wear time per day with a compliance rate of more than 65%. Thigh placement resulted in higher compliance than lower back placement. Achieving days with 24h wear time reduces the need for arbitrary decisions regarding wear time validation, and most likely improves the validity of daily life PA measurements.

Implementing 360° Quantified Self for childhood obesity: feasibility study and experiences from a weight loss camp in Qatar

Fernandez-Luque L, Singh M, Ofli F, Mejova YA, Weber I, Aupetit M, Jreige SK, Elmagarmid A, Srivastava J, Ahmedna M.

BMC medical informatics and decision making (2017)

Abstract: Background: The explosion of consumer electronics and social media are facilitating the rise of the Quantified Self (QS) movement where millions of users are tracking various aspects of their daily life using social media, mobile technology, and wearable devices. Data from mobile phones, wearables a... Background: The explosion of consumer electronics and social media are facilitating the rise of the Quantified Self (QS) movement where millions of users are tracking various aspects of their daily life using social media, mobile technology, and wearable devices. Data from mobile phones, wearables and social media can facilitate a better understanding of the health behaviors of individuals. At the same time, there is an unprecedented increase in childhood obesity rates worldwide. This is a cause for grave concern due to its potential long-term health consequences (e.g., diabetes or cardiovascular diseases). Childhood obesity is highly prevalent in Qatar and the Gulf Region. In this study we examine the feasibility of capturing quantified-self data from social media, wearables and mobiles within a weight lost camp for overweight children in Qatar. Methods: Over 50 children (9–12 years old) and parents used a wide range of technologies, including wearable sensors (actigraphy), mobile and social media (WhatsApp and Instagram) to collect data related to physical activity and food, that was then integrated with physiological data to gain insights about their health habits. In this paper, we report about the acquired data and visualization techniques following the 360° Quantified Self (360QS) methodology (Haddadi et al., ICHI 587–92, 2015). Results: 360QS allows for capturing insights on the behavioral patterns of children and serves as a mechanism to reinforce education of their mothers via social media. We also identified human factors, such as gender and cultural acceptability aspects that can affect the implementation of this technology beyond a feasibility study. Furthermore, technical challenges regarding the visualization and integration of heterogeneous and sparse data sets are described in the paper. Conclusions: We proved the feasibility of using 360QS in childhood obesity through this pilot study. However, in order to fully implement the 360QS technology careful planning and integration in the health professionals’ workflow is needed. Trial Registration: The trial where this study took place is registered at ClinicalTrials.gov on 14 November 2016 (NCT02972164).

Generating ActiGraph Counts from Raw Acceleration Recorded by an Alternative Monitor.

Brønd JC, Andersen LB, Arvidsson D.

Medicine and science in sports and exercise (2017)

Abstract: Purpose: To implement an aggregation method in Matlab for generating ActiGraph counts from raw acceleration recorded with an alternative accelerometer device and to investigate the validity of the method. Methods: The aggregation method including the frequency band-pass filter was implemented and op... Purpose: To implement an aggregation method in Matlab for generating ActiGraph counts from raw acceleration recorded with an alternative accelerometer device and to investigate the validity of the method. Methods: The aggregation method including the frequency band-pass filter was implemented and optimized based on standardized sinusoidal acceleration signals generated in Matlab and processed in the ActiLife software. Evaluating the validity of the aggregation method was approached using a mechanical setup and with a 24-hour free-living recording using a convenient sample of nine subjects. Counts generated with the aggregation method applied to Axivity AX3 raw acceleration data were compared to counts generated with ActiLife from ActiGraph GT3X+ data. Results: An optimal band-pass filter was fitted resulting in a root mean squared error (RMSE) of 25.7 counts per 10 second and mean absolute error (MAE) of 15.0 counts per second across the full frequency range. The mechanical evaluation of the proposed aggregation method resulted in an absolute mean (sd) difference of -0.11 (0.97) counts per 10 second across all rotational frequencies compared to the original ActiGraph method. Applying the aggregation method to the 24-hour free-living recordings resulted in an epoch level bias ranging from -16.2 to 0.9 counts per 10 second, a relative difference in the averaged physical activity (counts per minute) ranging from -0.5% to 4.7% with a group mean (sd) of 2.2% (1.7%) and a Cohen's Kappa of 0.945 indicating almost a perfect agreement in the intensity classification. Conclusion: The proposed band-pass filter and aggregation method is highly valid for generating ActiGraph counts from raw acceleration data recorded with alternative devices. It would facilitate comparability between studies using different devices collecting raw acceleration data.

A small amount of precisely measured high-intensity habitual physical activity predicts bone health in pre-and post-menopausal women in UK Biobank

Stiles VH, Metcalf BS, Knapp KM, Rowlands AV.

International Journal of Epidemiology (2017)

Abstract: Background: Physical inactivity is a highly modifiable risk factor for the development of osteoporosis but, due to a lack of research that has precisely and objectively meaured physical activity (PA) relevant to bone, the specific contribution that PA can make to bone health is poorly understood. Th... Background: Physical inactivity is a highly modifiable risk factor for the development of osteoporosis but, due to a lack of research that has precisely and objectively meaured physical activity (PA) relevant to bone, the specific contribution that PA can make to bone health is poorly understood. This study examined whether a more precise measure of PA relelvant to bone was associated with meaures of bone health in pre- and post-menopausal women in UK Biobank. Methods: Time spent at intensities specific to bone health [≥750 milli-gravitational units (mg) and ≥1000 mg] were analysed from raw tri-axial acceleration data averaged over 1-second epochs from 7-day monitoring of habitual PA using accelerometry-based activity monitors (100 Hz; AX3, Axivity, UK) of 1218 pre- and 1316 post-menopausal healthy women. In a cross-sectional analysis, associations between categories of time (<1, 1–2 and ≥2 minutes) spent above the intensity thresholds and calcaneal quantitative ultrasound measures of bone health (bone mineral density T-score, BMDT-score; speed of sound, SOS; and broadband ultrasound attenuation, BUA) were examined. Results: Compared with <1 minute, spending 1–2 or ≥2 minutes/day at intensities ≥1000 mg in pre-menopausal and ≥750 mg in post-menopausal women was positively associated with BMDT-score, SOS and BUA. Conclusion: Brief bursts of high-intensity PA relevant to bone health can be captured by applying bone-specific thresholds of intensity to raw tri-axial accelerations averaged over 1-second epochs. Accumulating 1–2 minutes/day of high-intensity PA, equivalent to running in pre-menopausal women and slow jogging in post-menopausal women, is associated with better bone health.

Validity of Consumer-Based Physical Activity Monitors for Estimating Energy Expenditure in Youth

Blythe A, Scott E, LaMunion MS, Samuel R.

University of Tennessee Honors Thesis Projects (2017)

Abstract: Physical activity (PA) has been shown to reduce the risk of a variety of health issues in youth, such as, obesity (43), diabetes (38), and depression (22,38). The current PA recommendations for youth include obtaining a minimum of 60 minutes of moderate intensity PA per day (43). It is also recommen... Physical activity (PA) has been shown to reduce the risk of a variety of health issues in youth, such as, obesity (43), diabetes (38), and depression (22,38). The current PA recommendations for youth include obtaining a minimum of 60 minutes of moderate intensity PA per day (43). It is also recommended that muscle strengthening activities be included at least three days per week. Lastly, incorporating vigorousintensity activities three days per week is advised (43). As our understanding of the importance of PA in youth continues to grow, the ability to accurately track this behavior is a necessity; commonly expressed as an estimate of daily energy expenditure (EE) or time spent in sedentary behaviors, and light, moderate, and vigorous PA. Daily PA can also be examined using the following domains: occupational, domestic, transportation, and leisure. PA is defined as any use of skeletal muscle that results in increased EE above the resting value (5). The amount of energy expended to complete PA can be expressed as a metabolic equivalent of task, or MET. While an adult has an estimated resting metabolic rate (RMR) of 3.5 mL of oxygen per kg of body weight per minute, which equals 1 MET, the RMR of youth is higher than adults. Thus, a youth MET is defined as the oxygen cost of an activity divided by a measured or predicted RMR. Common prediction equations of RMR in youth include the Schofield and Harrell equations (34, 40). Factors influencing youth resting metabolic rate include growth, puberty and differences in body mass (19). For measuring EE, doubly-labeled water, direct calorimetry, and indirect calorimetry are the gold standards (24,25,39). Doubly-labeled water is ideal for assessing total EE over an extended period of time. Direct and indirect calorimetry are ideal for shorter, more flexible periods of time. EE can also be estimated using a variety of objective measures. Objective measures include pedometers, heart rate monitors, and accelerometers. Of these objective measures, the most commonly used device is the accelerometer. Accelerometers that are most often used in research include the ActiGraph (10,16,44), GENEActiv (14,31), activPAL (20,33), and Axivity (26). These accelerometers are specifically designed for research and clinical uses. Consumergrade accelerometers are specifically marketed to the general population. Along with EE, these devices also provide information about steps taken, total distance traveled, and minutes of exercise. Importantly, the consumer models are often validated by a variety of methods including indirect calorimetry or by comparisons to research grade models (17). Some of these consumer PA monitors are the Apple Watch Series 2, the FitBit Charge 2, the Samsung Gear Fit 2, the Mymo Activity Tracker, and the Misfit Shine 2. Though consumer models have become increasingly popular, the research on these monitors focuses on adult populations (6,13,17,18,23). Because of this, validation studies need to be conducted to determine if these consumer models accurately estimate EE in youth.

A feasibility study into the measurement of physical activity levels of adults with intellectual disabilities using accelerometers and the International Physical Activity Questionnaire

Dairo YM, Collett J, Dawes H.

British Journal of Learning Disabilities (2017)

Abstract: Background: Few studies have measured physical activity (PA) levels of adults with intellectual disabilities using both objective and subjective methods, but none included individuals with profound intellectual disabilities. To inform effective measurement of PA across the disability spectrum, this ... Background: Few studies have measured physical activity (PA) levels of adults with intellectual disabilities using both objective and subjective methods, but none included individuals with profound intellectual disabilities. To inform effective measurement of PA across the disability spectrum, this study explored: the feasibility of measuring PA levels using the International Physical Activity Questionnaire-short version (IPAQ-s) and a wrist-worn 7-day accelerometer; examined the level of agreement between instruments/raters; and established the recruitment rate. From the literature reviewed, no study has investigated these issues. Materials and Methods: Two-hundred adults with intellectual disabilities from a local authority lists in UK were invited to participate. Participants were administered an accelerometer for seven days and the IPAQ-s (self and carer-reported). Results: Twenty participants with mild to profound intellectual disabilities (20–70 years) were recruited. The response rate was significantly different between home (16%) and residential homes (4%): χ2(1) = 7.7, p < .05. All participants completed the IPAQ-s but only 15 completed 7-day accelerometer. Self and carer-reported PA had perfect agreement on IPAQ-s, and agreements between instruments using PA guidelines was substantial (k = 0.6, p < .05). However, mean moderate-vigorous PA min/week differed between measures at 145 and 207 from IPAQ-s and accelerometer respectively. Conclusions: Recruitment demonstrated a need for better engagement with residential homes. While both the IPAQ-s and accelerometers can be used to evaluate PA levels, the IPAQ-s was more acceptable and carer report was accurate, but it underestimated absolute moderate-vigorous PA levels. These findings indicate that IPAQ-s can be used to measure PA levels, including in those with profound intellectual disabilities.

Are children participating in a quasi-experimental education outside the classroom intervention more physically active?.

Schneller MB, Duncan S, Schipperijn J, Nielsen G, Mygind E, Bentsen P.

BMC public health (2017)

Abstract: Background: Education outside the classroom (EOtC) is a curriculum-based approach to teaching that has shown positive associations with children’s physical activity and academic learning in small-scale case studies. The purpose of this large-scale quasi-experimental study was to determine if child... Background: Education outside the classroom (EOtC) is a curriculum-based approach to teaching that has shown positive associations with children’s physical activity and academic learning in small-scale case studies. The purpose of this large-scale quasi-experimental study was to determine if children who participate regularly in EOtC spend more time being physically active than children who do not. Methods: In the 2014/2015 study TEACHOUT, classes were recruited in pairs such that each EOtC class had a non-EOtC comparison class at the same school and grade level. Participants in 17 EOtC classes and 16 comparison parallel classes across Denmark wore an Axivity AX3 accelerometer taped to the lower back for seven consecutive days. Data from 201 EOtC participants (63.3% girls, age 10.82 ± 1.05,) and 160 comparison participants (59.3% girls, age 10.95 ± 1.01) were analysed using an ‘intention to treat’ (ITT) approach. The amount of EOtC the participants were exposed to was monitored. Associations between time spent in different physical activity intensities and EOtC group and sex were assessed using generalised linear models adjusted for age. In a second analysis, we modified the sample using a ‘per protocol’ (PP) approach, only including EOtC and comparison class pairs where the EOtC class had >150 min and the comparison had <150 min of EOtC during the measured week. Results: On average, EOtC participants spent 8.4 (ITT) and 9.2 (PP) minutes more in moderate-to-vigorous physical activity (MVPA) per day than comparison participants (p < 0.05). However, EOtC boys spent 18.7 (ITT) and 20.8 (PP) minutes more in MVPA per day than comparison boys (p < 0.01), while there were no significant between-group differences for girls. Conclusions: For boys, EOtC was associated with more daily time being spent moderately and vigorously physically active. No differences were observed for girls. Implementing EOtC into schools’ weekly practice can be a time- and cost-neutral, supplementary way to increase time spent in PA for boys through grades three to six. Trial registration: The Scientific Ethical Committee in the Capital Region of Denmark protocol number H-4-2014-FSP. 5 March, 2014.

hildren’s physical activity during a segmented school week: results from a quasi-experimental education outside the classroom intervention

Schneller MB, Schipperijn J, Nielsen G, Bentsen P.

BMC International Journal of Behavioral Nutrition and Physical Activity (2017)

Abstract: Background: Movement integration (MI) into traditional classroom teaching is a promising opportunity for children to increase physical activity (PA). Education outside the classroom (EOtC) can be regarded as MI, and has increased children’s PA in case studies. The aim of this study is to investiga... Background: Movement integration (MI) into traditional classroom teaching is a promising opportunity for children to increase physical activity (PA). Education outside the classroom (EOtC) can be regarded as MI, and has increased children’s PA in case studies. The aim of this study is to investigate the effects of EOtC on children’s PA by segmenting weekly activity-related behavior into a range of day types and domains. Methods: In a quasi-experimental design, 33 classes were recruited and participants’ PA was objectively measured using accelerometers taped to the lower back. In total, 361 (10.89 ± 1.03 years) participants with 7 days of 24 h wear time per day were included in a day type PA analysis, and 194 of these participants (10.46 ± 0.99 years) provided information on time spent in specific domains (e.g. EOtC or recess) and were included in a domain-specific PA analysis. Differences in proportion of time spent in PA intensities were tested using mixed-effects regression models. Results: More moderate-to-vigorous physical activity (MVPA) occurred on days with physical education (PE) than days with EOtC (girls 0.79%, p = .001, CI = .26% to 1.31%; boys 1.35%, p = .003, CI = .32% to 2.38%), while no difference was found between EOtC days and school days without EOtC and PE. Light physical activity (LPA) was higher on EOtC days than school days without EOtC and PE (girls 2.43% p < .001, CI = 1.21% to 3.65%; boys 2.08%, p < .001, CI = .69% to 3.47%) and PE days (girls 2.18%, p < .001, CI = .80% to 3.56%; boys 2.40%, p < .001, CI = .83% to 3.96%). Comparing EOtC and classroom domains, boys proportionally spent 7.95% (p < .001, CI = 3.00% to 12.90%) more time in MVPA while no difference (p = 1.000) was measured for LPA, and girls had no difference (p = .176) in MVPA, but spent 9.76% (p < .001, CI = 7.12% to 12.41%) more time in LPA. Conclusions: EOtC was implemented without the provision of additional resources and with positive effects on PA. Findings suggest EOtC as a way to provide children with an additional opportunity to accumulate PA within the existing school setting.

Stress in School. Some Empirical Hints on the Circadian Cortisol of Children in Outdoor and Indoor Classes

Dettweiler U, Becker C, Auestad BH, Simon P, Kirsch P.

International Journal of Environmental Research and Public Health (2017)

Abstract: This prospective longitudinal survey compared the stress levels of students taught using an outdoor curriculum in a forest, with children in a normal school setting. We were especially interested in the effect outdoor teaching might have on the children’s normal diurnal cortisol rhythm. 48 childre... This prospective longitudinal survey compared the stress levels of students taught using an outdoor curriculum in a forest, with children in a normal school setting. We were especially interested in the effect outdoor teaching might have on the children’s normal diurnal cortisol rhythm. 48 children (mean age = 11.23; standard deviation (SD) = 0.46) were enrolled, with 37 in the intervention group (IG), and 11 in the control group (CG). The intervention consisted of one full school day per week in the forest over the school year. Stress levels were measured in cortisol with three samples of saliva per day. Furthermore, the data allowed for statistical control of physical activity (PA) values. For data analysis, we used a linear mixed-effects model (LMM) with random intercept and general correlation matrix for the within-unit residuals. The LMM yields that IG have expected greater decline of cortisol compared to CG; rate 0.069 μg/L vs. 0.0102 μg/L (log-units/2 h), p = 0.009. PA does not show a statistically significant interaction with cortisol (p = 0.857), despite being higher in the intervention group (p < 0.001). The main effect in our measures was that the IG had a steady decline of cortisol during the school day. This is in accordance with a healthy child’s diurnal rhythm, with a significant decline of cortisol from morning to noon. This effect is constant over the school year. The CG does not show this decline during either measurement day. Further research is needed to fully explain this interesting phenomenon.

Move the Neighbourhood: Study design of a community-based participatory public open space intervention in a Danish deprived neighbourhood to promote active living

Pawlowski CS, Winge L, Carroll S, Schmidt T, Wagner AM, Nørtoft KP, Lamm B, Kural R, Schipperijn J, Troelsen J.

BMC public health (2017)

Abstract: Background: A limited amount of research has examined the effect of changing public open spaces on active living. This paper will present the study protocol of a community-based intervention study co-designed in an interdisciplinary collaboration with community members to develop urban installations... Background: A limited amount of research has examined the effect of changing public open spaces on active living. This paper will present the study protocol of a community-based intervention study co-designed in an interdisciplinary collaboration with community members to develop urban installations highly tailored to promote active living among children (10–13-years-old) and seniors (>60-years-old) in a deprived neighbourhood in Copenhagen. Methods: The study builds on a quasi-experimental study design with two sub-studies: 1) a children study and 2) a senior study. The interventions will be developed, designed and implemented in collaboration with local children and seniors, respectively, using different co-design tools and methods. We will evaluate the effect of the interventions on children’s and senior’s use of the new-built urban installations using accelerometers in combination with GPS as well as systematic observation using the System for Observing Play and Recreation in Communities (SOPARC). A process evaluation with focus groups consisting of the various stakeholders in the two sub-studies will be used to gain knowledge of the intervention processes. Discussion: The paper presents new approaches in the field of public open space interventions through interdisciplinary collaboration, participatory co-design approach and combination of measurements. Using both effect and process evaluations the study will provide unique insights in the role and importance of the interdisciplinary collaboration, participatory processes, and tailoring changes in public open space to local needs and wishes. These results can be used to guide urban renewal projects in deprived neighbourhoods in the future. Trial registration: Retrospectively registered with study ID ISRCTN50036837. Date of registration: 16 December 2016.

UK Biobank: opportunities for cardiovascular research

Littlejohns TJ, Sudlow C, Allen NE, Collins R.

European Heart Journal (2017)

Abstract: Cardiovascular diseases are a major cause of morbidity and mortality, accounting for 45% of all deaths in European countries in 20161 and almost a third of deaths worldwide in 2013.2 A similar pattern is observed in the UK where cardiovascular diseases were responsible for 27% of deaths in 2014, wit... Cardiovascular diseases are a major cause of morbidity and mortality, accounting for 45% of all deaths in European countries in 20161 and almost a third of deaths worldwide in 2013.2 A similar pattern is observed in the UK where cardiovascular diseases were responsible for 27% of deaths in 2014, with coronary heart disease resulting in the largest number of deaths attributable to a single cause (n = ∼69 000) whilst stroke is the third biggest cause (n = ∼39 000).3 Although age-standardized cardiovascular disease mortality rates are decreasing worldwide, the total deaths and burden as measured through disability-adjusted life years of cardiovascular diseases are increasing.4,5 Furthermore, in the UK, cardiovascular risk factors such as high blood pressure and high cholesterol are among the leading causes of disease burden.6 Epidemiological studies have historically played an essential role in identifying the causes and consequences of cardiovascular disease and have resulted in improvements in prevention and treatment. The seminal US-based Framingham Heart Study which recruited 5200 participants between 1948 and 1952, was integral in identifying a range of important risk factors for cardiovascular disease, such as high blood pressure, a high cholesterol level, cigarette smoking, obesity and physical inactivity, and consequently shifted the focus from management to preventative strategies for cardiovascular disease.7 This, together with findings from other epidemiological studies, such as the Seven Countries Study and the MONICA project,8 have been influential in leading to treatments for the primary and secondary prevention of cardiovascular events, most notably statins (that act to lower cholesterol levels), and anithypertensives.9,10 Epidemiological studies such as the Framingham Heart Study with moderate sample sizes are useful in detecting risk factors with large effects on common outcomes; however, they lack statistical power to reliably identify risk factors which have small to moderate effects or to assess associations with disease across subgroups of the population. The need for large sample sizes has led to collaborative efforts, such as the Prospective Studies Collaboration (an individual participant meta-analysis of data from 61 studies and more than a million participants11) that has demonstrated conclusively that a continuous increase in blood pressure corresponds with an increased risk of vascular death across all age groups (see Figure 1 that illustrates the importance of a large sample size (about 500 000 participants) for detecting this association).12 Sample size is also of particular importance in the current era of genome-wide association studies, where many investigations are aiming to detect either small effects from common variants or large effects from rare variants.13

Fitness, Physical Activity, And Cardiovascular Disease: Longitudinal And Genetic Analyses In The UK Biobank Study

Tikkanen E, Gustafsson S, Ingelsson E.

bioRxiv (2017)

Abstract: Background: Exercise is inversely related with cardiovascular disease (CVD), but large-scale studies of incident CVD events are lacking. Moreover, little is known about genetic determinants of fitness and physical activity, and modifiable effects of exercise in individuals with elevated genetic risk... Background: Exercise is inversely related with cardiovascular disease (CVD), but large-scale studies of incident CVD events are lacking. Moreover, little is known about genetic determinants of fitness and physical activity, and modifiable effects of exercise in individuals with elevated genetic risk of CVD. Finally, causal analyses of exercise traits are limited. Methods: We estimated associations of grip strength, physical activity, and cardiorespiratory fitness with CVD and all-cause death in up to 502,635 individuals from the UK Biobank. We also examined these associations in individuals with different genetic burden on coronary heart disease (CHD) and atrial fibrillation (AF). Finally, we performed genome-wide association study (GWAS) of grip strength and physical activity, as well as Mendelian randomization analysis to assess the causal role of grip strength in CHD. Findings: Grip strength, physical activity, and cardiorespiratory fitness showed strong inverse associations with incident cardiovascular events and all-cause death (for composite CVD; HR, 0.78, 95% CI, 0.77-0.80; HR, 0.94, 95% CI, 0.93-0.95, and HR, 0.67, 95% CI, 0.63-0.71, per SD change, respectively). We observed stronger associations of grip strength with CHD and AF for individuals in the lowest tertile of genetic risk (Pinteraction=0.006, Pinteraction=0.03, respectively), but the inverse associations were present in each category of genetic risk. We report 27 novel genetic loci associated with grip strength and 2 loci with physical activity, with the strongest associations in FTO (rs56094641, P=3.8*10e-24) and SMIM2 (rs9316077, P=1.4*10e-8), respectively. By use of Mendelian randomization, we provide evidence that grip strength is causally related to CHD. Interpretation: Maintaining physical strength is likely to prevent future cardiovascular events, also in individuals with elevated genetic risk for CVD.

Effect of team sports and resistance training on physical function, quality of life, and motivation in older adults

Pedersen MT, Vorup J, Nistrup A, Wikman JM, Alstrøm JM, Melcher PS, Pfister GU, Bangsbo J.

Scandinavian Journal of Medicine & Science in Sports (2017)

Abstract: The aim of this study was to investigate the effect of team sports and resistance training on physical function, psychological health, quality of life, and motivation in older untrained adults. Twenty-five untrained men and forty-seven untrained women aged 80 (range: 67-93) years were recruited. Fif... The aim of this study was to investigate the effect of team sports and resistance training on physical function, psychological health, quality of life, and motivation in older untrained adults. Twenty-five untrained men and forty-seven untrained women aged 80 (range: 67-93) years were recruited. Fifty-one were assigned to a training group (TRG) of which twenty-five performed team training (TG) and twenty-six resistance training (RG). The remaining twenty-one were allocated to a control group (CG). TRG trained for 1 hour twice a week for 12 weeks. Compared with CG, TRG improved the number of arm curls within 30 seconds (P<.05) and 30-seconds chair stand (P<.05) during the intervention. In TRG, participation in training led to higher (P<.05) scores in the subscales psychological well-being, general quality of life, and health-related quality of life, as well as decreased anxiety and depression levels. No differences between changes in TG and RG were found over the intervention period, neither in physical function tests nor psychological questionnaires. Both TG and RG were highly motivated for training, but TG expressed a higher degree of enjoyment and intrinsic motivation mainly due to social interaction during the activity, whereas RG was more motivated by extrinsic factors like health and fitness benefits. In conclusion, both team training and resistance training improved physical function, psychological well-being, and quality of life. However, team sport training motivated the participants more by intrinsic factors than resistance training.

Internet of Things based activity surveillance of defence personnel

Bhatia M, Sood SK.

Journal of Ambient Intelligence and Humanized Computing (2017)

Abstract: Developments in Internet of Things (IoT) Technology have been effectively utilized in different industrial sectors for monitoring, surveillance, and remote decision-making. The ability to acquire in-depth information about ubiquitous events has proliferated numerous opportunities for using this tech... Developments in Internet of Things (IoT) Technology have been effectively utilized in different industrial sectors for monitoring, surveillance, and remote decision-making. The ability to acquire in-depth information about ubiquitous events has proliferated numerous opportunities for using this technology in sensitive domains like national defence security. In this paper, a comprehensive IoT-based framework is presented for analyzing national integrity of defence personnel with consideration to his/her daily activities. As reported by investigating agencies of many countries, routinely engagements of defence personnel are one of the premier reasons for vulnerability to national defence through intentional and unintentional information outflow of defence secrets. The work presented in this research is focused on monitoring various activities of defence personnel to determine his/her integral behavior in daily life. Specifically, Integrity Index Value is defined for every defence personnel based on different social engagements, and activities for detecting the vulnerability to national security. In addition to this, a probabilistic decision tree based automated decision making is presented to aid defence officials in analyzing various activities of a defence personnel for his/her integrity assessment. In order to validate the proposed framework, three challenging data sets have been considered for experimental evaluation. The computed results are compared with the state-of-the-art techniques for overall assessment. Results show that the proposed model achieves better performance in monitoring and analyzing activities of defence personnel for effective decision making.

A comprehensive health assessment framework to facilitate IoT-assisted smart workouts: A predictive healthcare perspective

Bhatia M, Sood SK.

Computers in Industry (2017)

Abstract: Enormous potential of Internet of Things (IoT) Technology has made it feasible to perceive and analyze real time health conditions in ubiquitous manner. Moreover, incorporation of IoT in healthcare industry has led researchers around the world to develop smart applications like mobile healthcare, he... Enormous potential of Internet of Things (IoT) Technology has made it feasible to perceive and analyze real time health conditions in ubiquitous manner. Moreover, incorporation of IoT in healthcare industry has led researchers around the world to develop smart applications like mobile healthcare, health-aware recommendations, and intelligent healthcare systems. Inspired from these aspects, this research presents an intelligent healthcare framework based on IoT Technology to provide ubiquitous healthcare to person during his/her workout sessions. The intelligence of the presented framework lies with its ability to analyze real time health conditions during workouts and predict probabilistic health state vulnerability. For predictive purpose, the proposed framework indulges the utilization of Artificial Neural Network (ANN) model, which is comprised of three phases namely, monitor, learn, and predict. In addition to this, the presented framework is supported by a mathematical foundation to predict probabilistic vulnerability, in terms of Probabilistic State of Vulnerability (PSoV). In order to determine the validity and applicability of the proposed framework, experiments were performed where 5 people with different attributes are monitored for 14 days using numerous smart sensors. Results, upon comparison with various state-of-the-art techniques, depict that the proposed system is superior in performance and is highly effective in delivering healthcare services during workouts.

Remote Actigraphy for Quantitative Assessment of Walking Speed in People with MS

Supratak, A., Datta, G., Wu, C., Yu, S., D'Arcy, C., Nicholas, R., Guo, Y. and Matthews, P.

Neurology 86.16 Supplement (2016)

Abstract: Objective: To design a wearable actigraphy device and enable subject-specific remote calibration for accurate estimation of walking speeds across a wide disability range. Background: Remote actigraphy has become popular a source of data regarding activity, but existing systems for estimating walkin... Objective: To design a wearable actigraphy device and enable subject-specific remote calibration for accurate estimation of walking speeds across a wide disability range. Background: Remote actigraphy has become popular a source of data regarding activity, but existing systems for estimating walking speed suffer high estimation errors because of individual differences in gait biomechanics. In people with MS, these errors vary with disability. We describe an approach to address this limitation. Methods: An AX3-Axivity triaxial-accelerometer (http://axivity.com/product/ax3) protected with silicone backing and attached to the trunk with surgical tape allows > 7 days of continuous data acquisition. Data analysis involves: 1) Feature extraction - deriving 29 features characterizing trunk acceleration with each step; 2) Initial calibration - Support-Vector-Regression subject-specific models relating features to gait speed during a Timed 25-Foot Walk and 2-Minute Walk; 3) Remote calibration - GPS positions from a smartphone app update calibration with “real-life” gait; 4) Database - patient-centre data repository in WikiHealth (http://www.wiki-health.org/about/overview.php). Results: Actigraphy data from 10 healthy (mean speed, 1.05±0.45m/s; error, 0.01±0.05m/s) and 7 MS subjects (EDSS scores 1.0-5.5, mean speed, 1.05±0.35m/s; error, -0.03±0.10m/s) was used to accurately estimate walking speeds. It also showed a potential for high estimation error if only the initial calibration is applied to “real-life” outdoor gait (mean speed, 1.09±0.49m/s; error, -0.17±0.16m/s). However, with a remote GPS calibration update, mean estimation error can be reduced to -0.01±0.06m/s. >80[percnt] of subjects tolerated chronic attachment of the device on the trunk. Conclusions: Remote actigraphy can accurately measure walking speed for both healthy volunteers and people with MS across a range of disability. This may provide a new tool for assessing treatment effectiveness based on a well accepted measure of disability. Study supported by: Progressive MS Alliance, Imperial College Healthcare Trust Biomedical Research Centre.

SELFBACK—Activity Recognition for Self-management of Low Back Pain

Sani, S., Wiratunga, N., Massie, S. and Cooper, K

Research and Development in Intelligent Systems XXXIII: Incorporating Applications and Innovations in Intelligent Systems XXIV (2016)

Abstract: Low back pain (LBP) is the most significant contributor to years lived with disability in Europe and results in significant financial cost to European economies. Guidelines for the management of LBP have self-management at their cornerstone, where patients are advised against bed rest, and to remain... Low back pain (LBP) is the most significant contributor to years lived with disability in Europe and results in significant financial cost to European economies. Guidelines for the management of LBP have self-management at their cornerstone, where patients are advised against bed rest, and to remain active. In this paper, we introduce SELFBACK, a decision support system used by the patients themselves to improve and reinforce self-management of LBP. SELFBACK uses activity recognition from wearable sensors in order to automatically determine the type and level of activity of a user. This is used by the system to automatically determine how well users adhere to prescribed physical activity guidelines. Important parameters of an activity recognition system include windowing, feature extraction and classification. The choices of these parameters for the SELFBACK system are supported by empirical comparative analyses which are presented in this paper. In addition, two approaches are presented for detecting step counts for ambulation activities (e.g. walking and running) which help to determine activity intensity. Evaluation shows the SELFBACK system is able to distinguish between five common daily activities with 0.9 macro-averaged F1 and detect step counts with 6.4 and 5.6 root mean squared error for walking and running respectively.

Using Accelerometers in the Neurological ICU to Monitor Unilaterally Motor Impaired Patients

LaBuzetta, J., Hermiz, J., Gilja, V. and Karanjia, N.

Neurology 86.16 Supplement (2016)

Abstract: Objective: We explore the feasibility of automating motor function scoring by using continuous accelerometer measurements to identify characteristics present in both accelerometer recordings and motor exam scores. Background: The neurological motor exam provides important information about a patien... Objective: We explore the feasibility of automating motor function scoring by using continuous accelerometer measurements to identify characteristics present in both accelerometer recordings and motor exam scores. Background: The neurological motor exam provides important information about a patient’s clinical status in the ICU, but the frequency at which it needs to be performed often makes it arduous for both healthcare providers and patients. Methods: Patients with unilateral motor impairment (defined as a score of 0-2 on “weak” side compared with 3-5 on “normal” side) in the neurological ICU were considered for this study. The Axivity AX3 accelerometer was used to measure three-dimensional accelerations for up to 14 days in each patient. These unobtrusive devices were placed on all 4 limbs using standard hospital bands, and required no active maintenance. Acceleration signals were processed to identify movement events that lasted ≥0.5msec. Movement events per hour were summated and compared between “weak” and “normal” limbs, and average movement count per hour was compared against motor strength score. Results: Three subjects were recruited; mean age 44years, 67[percnt] male. Two patients were diagnosed with ischemic strokes, and one with hemorrhagic stroke. One subject was impaired on the left hemibody; two were right-side impaired. The mean recording duration was 10 days (range 6-14 days). We found that there were significantly more movements in each of the normal upper and lower extremities as compared to their respective weak upper and lower extremities for all 3 subjects (P < 0.05, one-tail, two sample Kolmogorov-Smirnov test). Moreover, mean movement counts per hour appeared to correlate with objective provider motor scoring. Conclusions: Continuous monitoring of limb activity with accelerometers is feasible and can be used to identify motor asymmetry after neurological injury. It is unclear if accelerometer monitoring can be used to assess nuanced motor function.

Measuring acceleration of ballast particles at track level

Milne, D., Le Pen, L.M., Watson, G., Thompson, D.J., Powrie, W., Hayward, M. and Morley, S.

Third International Conference on Railway Technology (2016)

Abstract: The maximum operational speed of high-speed railways has increased considerablysince the 1960s and is forecast to continue to rise. For example, routes being plannedtoday expected to attain opening speeds of at least 360 km/h. When ballasted tracksare used for higher speeds, ballast flight may be of... The maximum operational speed of high-speed railways has increased considerablysince the 1960s and is forecast to continue to rise. For example, routes being plannedtoday expected to attain opening speeds of at least 360 km/h. When ballasted tracksare used for higher speeds, ballast flight may be of concern. The mechanisms ofballast flight are still not fully understood but it is hypothesized that ballast particlescould become airborne owing to a combination of track bed excitation and air flowbeneath a passing train. To understand better the mechanics of ballast flightmeasurements of individual particle accelerations are highly desirable, yet these aredifficult to achieve. Trackside monitoring technologies generally provide data on theperformance of the track superstructure and the track bed, not individual ballastparticles. A novel measurement technique is presented. This is based on the use oflow cost MEMs accelerometers embedded within individual ballast particles, whichpermits measurements of the acceleration of ballast particles in three axes. Theutility of the method is demonstrated with reference to measurements from a sectionof well performing high speed track. Measurements of sleeper movements are alsopresented to demonstrate that there are differences in the motion of the ballast andthe track superstructure.

Accelerometer-based gait assessment: pragmatic deployment on an international scale

Del Din, S., Hickey, A., Woodman, S., Hiden, H., Morris, R., Watson, P., Nazarpour, K., Catt, M., Rochester, L. and Godfrey, A.

tatistical Signal Processing Workshop (SSP), IEEE (2016)

Abstract: Gait is emerging as a powerful tool to detect early disease and monitor progression across a number of pathologies. Typically quantitative gait assessment has been limited to specialised laboratory facilities. However, measuring gait in home and community settings may provide a more accurate reflect... Gait is emerging as a powerful tool to detect early disease and monitor progression across a number of pathologies. Typically quantitative gait assessment has been limited to specialised laboratory facilities. However, measuring gait in home and community settings may provide a more accurate reflection of gait performance because: (1) it will not be confounded by attention which may be heightened during formal testing; and (2) it allows performance to be captured over time. This work addresses the feasibility and challenges of measuring gait characteristics with a single accelerometer based wearable device during free-living activity. Moreover, it describes the current methodological and statistical processes required to quantify those sensitive surrogate markers for ageing and pathology. A unified framework for large scale analysis is proposed. We present data and workflows from healthy older adults and those with Parkinson's disease (PD) while presenting current algorithms and scope within modern pervasive healthcare. Our findings suggested that free-living conditions heighten between group differences showing greater sensitivity to PD, and provided encouraging results to support the use of the suggested framework for large clinical application.

Validity of a wearable accelerometer to quantify gait in spinocerebellar ataxia type 6

Hickey, A., Gunn, E., Alcock, L., Del Din, S., Godfrey, A., Rochester, L. and Galna, B.

Physiological Measurement 37.11 (2016)

Abstract: Biomarkers are required to track disease progression and measure the effectiveness of interventions for people with spinocerebellar ataxia type-6 (SCA6). Gait is a potential biomarker that is sensitive to SCA6 which can be measured using wearable technology, reducing the need for expensive specialis... Biomarkers are required to track disease progression and measure the effectiveness of interventions for people with spinocerebellar ataxia type-6 (SCA6). Gait is a potential biomarker that is sensitive to SCA6 which can be measured using wearable technology, reducing the need for expensive specialist facilities. However, algorithms used to calculate gait using data from wearables have not been validated in SCA6. This study sought to examine the validity of a single wearable for deriving 14 spatio-temporal gait characteristics in SCA6 and control cohorts. Participants performed eight intermittent walks along a 7 m instrumented walkway at their preferred walking pace while also wearing a single accelerometer-based wearable on L5. Gait algorithms previously validated in neurological populations and controls were used to derive gait characteristics. We assessed the bias, agreement and sensitivity of gait characteristics derived using the instrumented walkway and the wearable. Mean gait characteristics showed good to excellent agreement for both groups, although gait variability and asymmetry showed poor agreement between the two systems. Agreement improved considerably in the SCA6 group when people who used walking sticks were excluded from the analysis, suggesting poorer agreement in people with more severe gait impairment. Despite poor agreement for some characteristics, gait measured using the wearable was generally more sensitive to group differences than the instrumented walkway. Our findings indicate mean gait characteristics can be accurately measured using an accelerometer-based wearable in people SCA6 with mild-to-moderately severe gait impairment yet further development of algorithms are required for people with more severe symptoms.

Measuring gait with an accelerometer-based wearable: influence of device location, testing protocol and age

Del Din, S., Hickey, A., Hurwitz, N., Mathers, J.C., Rochester, L. and Godfrey, A.

Physiological Measurement 37.10 (2016)

Abstract: Wearables such as accelerometers are emerging as powerful tools for quantifying gait in various environments. Flexibility in wearable location may improve ease of use and data acquisition during instrumented testing. However, change of location may impact algorithm functionality when evaluating asso... Wearables such as accelerometers are emerging as powerful tools for quantifying gait in various environments. Flexibility in wearable location may improve ease of use and data acquisition during instrumented testing. However, change of location may impact algorithm functionality when evaluating associated gait characteristics. Furthermore, this may be exacerbated by testing protocol (different walking speed) and age. Therefore, the aim of this study was to examine the effect of an accelerometer-based wearable(s) (accW) location, walking speed, age and algorithms on gait characteristics. Forty younger (YA) and 40 older adults (OA) were recruited. Participants wore accW positioned at the chest, waist and lower back (L5, gold standard) and were asked to walk continuously for 2 min at preferred and fast speeds. Two algorithms, previously validated for accW located on L5, were used to quantify step time and step length. Mean, variability and asymmetry gait characteristics were estimated for each location with reference to L5. To examine impact of locations and speed on algorithm-dependant characteristic evaluation, adjustments were made to the temporal algorithm. Absolute, relative agreement and difference between measurements at different locations and L5 were assessed. Mean step time and length evaluated from the chest showed excellent agreement compared to L5 for both age groups and speeds. Agreement between waist and L5 was excellent for mean step time for both speeds and age groups, good for mean step length at both speeds for YA and at preferred speed for OA. Step time and length asymmetry evaluated from the chest showed moderate agreement for YA only. Lastly, results showed that algorithm adjustment did not influence agreement between results obtained at different locations. Mean spatiotemporal characteristics can be robustly quantified from accW at the locations used in this study irrespective of speed and age; this is not true when estimating variability and asymmetry characteristics.

Toward a low-cost gait analysis system for clinical and free-living assessment

Ladha, C., Del Din, S., Nazarpour, K., Hickey, A., Morris, R., Catt, M., Rochester, L. and Godfrey, A

Engineering in Medicine and Biology Society (EMBC), (2016)

Abstract: Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to bespoke clinical facilities until recently. The use of inexpensive wearable technologies is an attractive alternative and o... Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to bespoke clinical facilities until recently. The use of inexpensive wearable technologies is an attractive alternative and offers the potential to assess gait in any environment. In this paper we present the development of a low cost analysis gait system built using entirely open source components. The system is used to capture spatio-temporal gait characteristics derived from an existing conceptual model, sensitive to ageing and neurodegenerative pathology (e.g. Parkinson's disease). We demonstrate the system is suitable for use in a clinical unit and will lead to pragmatic use in a free-living (home) environment. The system consists of a wearable (tri-axial accelerometer and gyroscope) with a Raspberry Pi module for data storage and analysis. This forms ongoing work to develop gait as a low cost diagnostic in modern healthcare.

Effect of Communicating Phenotypic and Genetic Risk of Coronary Heart Disease Alongside Web-based Lifestyle Advice-The Inform Randomized Clinical

Silarova, B., Sharp, S.J., Usher-Smith, J.A., Lucas, J., Payne, R.A., Shefer, G., Moore, C., Girling, C., Lawrence, K., Tolkien, Z. and Walker, M.

Circulation. Epidemiology, population & big data (2016)

Abstract: Introduction: Coronary heart disease (CHD) risk scores based on phenotypic information are routinely used in primary care. It has been suggested that genetics could be used to more precisely identify individuals at high risk of developing disease and to more effectively motivate individuals to chang... Introduction: Coronary heart disease (CHD) risk scores based on phenotypic information are routinely used in primary care. It has been suggested that genetics could be used to more precisely identify individuals at high risk of developing disease and to more effectively motivate individuals to change their lifestyle. However, there is a lack of adequately powered randomized trials using objective measures to evaluate the effect of provision of phenotypic and genetic CHD risk information on health behaviours. Hypothesis: We aimed to quantify the short-term (12 weeks) effects of provision of phenotypic and genetic CHD risk information, alongside lifestyle advice, on change in objectively-measured health behaviours and cardiovascular risk factors. Methods: In a parallel-group, open randomized trial, we allocated 956 male and female blood donors (mean (SD) age = 56.7 (8.8)) with no previous history of CHD to either no intervention (control group) or to one of three active intervention groups: i) web-based lifestyle advice only; ii) lifestyle advice plus information on estimated 10-year CHD risk based on phenotypic characteristics; and iii) lifestyle advice plus information on estimated 10-year CHD risk based on phenotypic and genetic characteristics. The primary outcome was change in physical activity from baseline to 12 weeks (mean acceleration over 7 days measured by Axivity Accelerometer®). Secondary key outcome was: change in fruit and vegetable intake measured by serum carotenoids. Results: 928 (97.1%) participants completed the trial. There was no evidence of intervention effects on physical activity. There were also no evidence of intervention effects on serum carotenoids (difference in adjusted mean change from baseline): lifestyle advice only group vs control group 0.11μmol/l (95% CI: -0.04 to 0.26); genetic group vs phenotypic group -0.15μmol/l (95% CI: -0.30 to 0.00); phenotypic group and genetic group vs. control group 0.05μmol/l (95% CI: -0.08 to 0.18) and phenotypic group and genetic group vs. lifestyle group -0.07μmol/l (95% CI: -0.20 to 0.07). Conclusions: Provision of CHD risk information (based on phenotype or genotype) and web-based lifestyle advice are unlikely to enhance preventive strategies by influencing health behaviours.

Human authentication from ankle motion data using convolutional neural networks

Gadaleta, M., Merelli, L. and Rossi, M.

Statistical Signal Processing Workshop (SSP), IEEE (2016)

Abstract: We present a data acquisition and signal processing framework for the authentication of users from their gait signatures (accelerometer and gyroscope data). An ankle-worn inertial measurement unit (IMU) is utilized to acquire the raw motion data, which is pre-processed and used to train a number of ... We present a data acquisition and signal processing framework for the authentication of users from their gait signatures (accelerometer and gyroscope data). An ankle-worn inertial measurement unit (IMU) is utilized to acquire the raw motion data, which is pre-processed and used to train a number of signal processing tools, including a convolutional neural network (CNN) for the extraction of features as well as one-class single- and multi-stage classifiers. The CNN is trained (offline and only once) using a representative set of subjects and is then exploited as a universal feature extractor, i.e., to extract relevant features from walking patterns of previously unseen subjects. The one-class classifier is instead solely trained on the subject that we intend to authenticate (the target user). Scores from the one-class classifier are finally fed into a multi-stage decision maker, which performs a sequential decision testing for improved accuracy. The system operates in an online fashion, delivering excellent results, while requiring in the worst case fewer than five walking cycles to reliably authenticate the user.

Validation of the AX3 accelerometer for detection of common daily activties and postures

Kongsvold, A.M.

Master's thesis, NTNU (2016)

Abstract: Introduction: Sedentary behavior has been suggested as an independent risk factor for ill-health, with detrimental effects independent of physical activity. However, the exact effect of different types of activity i.e. lying, sitting, standing and walking, on health is uncertain. To obtain precise o... Introduction: Sedentary behavior has been suggested as an independent risk factor for ill-health, with detrimental effects independent of physical activity. However, the exact effect of different types of activity i.e. lying, sitting, standing and walking, on health is uncertain. To obtain precise objective measurements of different types of physical activity and sedentary behavior is therefore of great importance for further research in this field. This study aimed to develop and validate a setup with two tri-axial accelerometers to differentiate between common daily activities and postures. The activity classifiers were developed by use of machine learning algorithms. The classifiers were also compared with the existing benchmark activity classifier Acti4. Methods: Twenty-two adults (9 males, 13 females) were recruited to the study. Two accelerometers were fixed to the participants, one on the thigh and one on the upper back. The protocol for validation was divided into two sessions, one structured in-lab session emulating common daily activities, and one semi-structured out-of-lab session. Participants were filmed with a video camera during both sessions. The videos were later annotated frame-by-frame and used as criterion for validation. Accelerometer data and video data were synchronized and two different activity classifiers were created, one lab model trained on the structured session (NTNULAB-MODEL), and one model trained and tested on the complete dataset (NTNUADUL). A framework with definitions of activities, postures and transitions were also developed. Results: The IRR from video annotation were 0.96 (p<0.0001) between three raters. The overall weighted sensitivity of three models were 91% for NTNUADUL, and 87% for NTNULAB-MODEL and Acti4. The sensitivity was >92% for walking, running, standing, sitting, lying down and cycling in NTNUADUL, while specificity was >97% and accuracy >95%. NTNULAB-MODEL had a sensitivity of >89% for running, walking, standing, sitting and lying down. Acti4 had a sensitivity of >81% for the same activities. Conclusion: The activity classifiers developed in this study were able to detect and differentiate between common daily activities and postures with high sensitivity, specificity and accuracy.

Optical or Inertial? Evaluation of Two Motion Capture Systems for Studies of Dancing to Electronic Dance Music

Solberg, R.T. and Jensenius, A.R.

Proceedings of the SMC Conferences (2016)

Abstract: What type of motion capture system is best suited for studying dancing to electronic dance music? The paper discusses positive and negative sides of using camera-based and sensor-based motion tracking systems for group studies of dancers. This is exemplified through experiments with a Qualisys infra... What type of motion capture system is best suited for studying dancing to electronic dance music? The paper discusses positive and negative sides of using camera-based and sensor-based motion tracking systems for group studies of dancers. This is exemplified through experiments with a Qualisys infrared motion capture system being used alongside a set of small inertial trackers from Axivity and regular video recordings. The conclusion is that it is possible to fine-tune an infrared tracking system to work satisfactory for group studies of complex body motion in a “club-like” environment. For ecological studies in a real club setting, however, inertial tracking is the most scalable and flexible solution.

A systematic review of the characteristics and validity of monitoring technologies to assess Parkinson's disease

Godinho, C., Domingos, J., Cunha, G., Santos, A.T., Fernandes, R.M., Abreu, D., Gonçalves, N., Matthews, H., Isaacs, T., Duffen, J. and Al-Jawad, A.

Journal of neuroengineering and rehabilitation 13.1 (2016)

Abstract: Background: There is growing interest in having objective assessment of health-related outcomes using technology-based devices that provide unbiased measurements which can be used in clinical practice and scientific research. Many studies have investigated the clinical manifestations of Parkinson’... Background: There is growing interest in having objective assessment of health-related outcomes using technology-based devices that provide unbiased measurements which can be used in clinical practice and scientific research. Many studies have investigated the clinical manifestations of Parkinson’s disease using such devices. However, clinimetric properties and clinical validation vary among the different devices. Methods: Given such heterogeneity, we sought to perform a systematic review in order to (i) list, (ii) compare and (iii) classify technological-based devices used to measure motor function in individuals with Parkinson's disease into three groups, namely wearable, non-wearable and hybrid devices. A systematic literature search of the PubMed database resulted in the inclusion of 168 studies. These studies were grouped based on the type of device used. For each device we reviewed availability, use, reliability, validity, and sensitivity to change. The devices were then classified as (i) ‘recommended’, (ii) ‘suggested’ or (iii) ‘listed’ based on the following criteria: (1) used in the assessment of Parkinson’s disease (yes/no), (2) used in published studies by people other than the developers (yes/no), and (3) successful clinimetric testing (yes/no). Results: Seventy-three devices were identified, 22 were wearable, 38 were non-wearable, and 13 were hybrid devices. In accordance with our classification method, 9 devices were ‘recommended’, 34 devices were ‘suggested’, and 30 devices were classified as ‘listed’. Within the wearable devices group, the Mobility Lab sensors from Ambulatory Parkinson’s Disease Monitoring (APDM), Physilog®, StepWatch 3, TriTrac RT3 Triaxial accelerometer, McRoberts DynaPort, and Axivity (AX3) were classified as ‘recommended’. Within the non-wearable devices group, the Nintendo Wii Balance Board and GAITRite® gait analysis system were classified as ‘recommended’. Within the hybrid devices group only the Kinesia® system was classified as ‘recommended’.

Investigation of energy expenditure during walking in children with cerebral palsy and typically developing children using raw acceleration data

Maalen-Johansen, I.K.

Master's thesis, NTNU (2016)

Abstract: Background: Children with cerebral palsy (CP) experience motor disabilities which can lead to difficulties when walking. This is apparent in lower walking speed and higher energy expenditure (EE) when walking compared to typically developing (TD) peers, in addition to more sedentary time and lower p... Background: Children with cerebral palsy (CP) experience motor disabilities which can lead to difficulties when walking. This is apparent in lower walking speed and higher energy expenditure (EE) when walking compared to typically developing (TD) peers, in addition to more sedentary time and lower participation. EE estimations are often done in this group to investigate the effect of treatments. EE indicates the amount of energy used to perform a task and is commonly estimated from oxygen consumption (VO2) measurements using indirect calorimetry. A less invasive method is desirable, and activity monitors are now being used for this purpose. They measure acceleration during movement and relate the output to EE. Aim: To investigate if raw acceleration data can be used to estimate EE in children with CP and TD children during walking. Methods: Fifteen typically developing (TD) children (mean age 10.0 yrs ± 1.7) and six children with CP (mean age 12.4 yrs ± 3.9, GMFCS level I-III) performed a five-minute walking test at preferred walking speed while wearing two Axivity AX3 activity monitors (lower back and mid-thigh) and portable indirect calorimetry equipment (Metamax II). Distance walked was recorded with a measuring wheel. EE and relative VO2 was estimated from indirect spirometry and equations developed by Brandes et al. and Hildebrand et al, using vector magnitude (VM) from the acceleration signal as input. Results: EE and relative EE values from indirect calorimetry and acceleration data were almost identical, overestimating with 0.1% and 4.5% for the TD children and 4.8 % and 2.3% for the children with CP. Both equations estimating relative VO2 gave accurate estimations for the children with CP (1.2% and 3.4% overestimation), but a significant difference was seen between the relative VO2 from acceleration data and the values obtained by indirect calorimetry for the TD children (12.9% and 14.1%). A large variation was found in the accuracy of the estimations for each participant, with wide limits of agreement in a Bland-Altman analysis. There was not found a statistical difference in VM for the groups. The VM showed little variation in the acceleration signal during the test period (mean range 0.06 g for the TD children and 0.082 g for the children with CP). Conclusion: Accurate estimations of EE and relative VO2 during walking can be made on group level for TD children and children with CP, using raw acceleration data, but not on individual level.

A quasi-experimental cross-disciplinary evaluation of the impacts of education outside the classroom on pupils’ physical activity, well-being and learning: the TEACHOUT study protocol

Nielsen, G., Mygind, E., Bølling, M., Otte, C.R., Schneller, M.B., Schipperijn, J., Ejbye-Ernst, N. and Bentsen, P.

BMC Public Health 16.1 (2016)

Abstract: Background: Education Outside the Classroom (EOTC) is a teaching method that aims to promote schoolchildren’s learning, physical activity (PA), social relations, motivation, and well-being. EOTC activities are characterized by teachers using the local environment in their teaching, and involve inn... Background: Education Outside the Classroom (EOTC) is a teaching method that aims to promote schoolchildren’s learning, physical activity (PA), social relations, motivation, and well-being. EOTC activities are characterized by teachers using the local environment in their teaching, and involve innovative teaching methods, child-led approaches to problem-solving, experimentation, cooperation, PA, and play. EOTC has become common practice for many teachers in Scandinavia; however, only case studies have evaluated its impacts. The TEACHOUT study aims to evaluate the impacts of EOTC on Danish schoolchildren’s PA, social relations, motivation, well-being, and learning. Methods: TEACHOUT is a quasi-experimental, cross-disciplinary study. Sixteen schools participated, containing 19 EOTC school classes and 19 parallel non-EOTC classes, with a total of 834 children aged 9 to 13 years. Measures of the children’s social relations, motivation for school, well-being, and academic performance were collected at the beginning and end of the school year. Data on PA levels were collected over ten-day periods during the school year using accelerometers. The amount and characteristics of the actual EOTC provided in both EOTC and non-EOTC classes were monitored day-to-day throughout the school year, using an online teacher survey platform. The effects of EOTC are mainly analysed by comparing EOTC pupils to non-EOTC (i.e. control) pupils based on their scores on the outcome variables (i.e. school performance, well-being, motivation, and social relations) at the end of the school year, adjusting for the baseline values (from the beginning of the year). The impacts of EOTC on PA are evaluated by comparing the total as well as context-specific amounts of PA of children participating in EOTC to those of children in their parallel non-EOTC classes. Furthermore, the interdependencies between PA, social relations, well-being, motivation, and learning are explored using path analysis. To help describe and understand the processes that have led to the quantitative outcomes, qualitative case observations of children’s practices and interactions in EOTC as well as classroom teaching were carried out and combined with qualitative interviews about children’s perceptions of these practices. Discussion: The TEACHOUT study represents a holistic multidisciplinary approach to educational and school health-promotion research through its study design and combination of scientific disciplines and methods, as well as its focus on the interdependent relations between learning, PA, social relations, well-being, and motivation. This will result in a comprehensive picture of school health promotion and children’s health and well-being, which will broaden the understanding of the potential benefits of EOTC in school health promotion and primary education. These results can be used to inform and guide future policy and practice.

Porcine lie detectors: Automatic quantification of posture state and transitions in sows using inertial sensors

Thompson, R., Matheson, S.M., Plötz, T., Edwards, S.A. and Kyriazakis, I.

Computers and Electronics in Agriculture 127 (2016)

Abstract: This paper presents a novel approach to automated classification and quantification of sow postures and posture transitions that may enable large scale and accurate continuous behaviour assessment on farm. Automatic classification and quantification of postures and posture transitions in domestic an... This paper presents a novel approach to automated classification and quantification of sow postures and posture transitions that may enable large scale and accurate continuous behaviour assessment on farm. Automatic classification and quantification of postures and posture transitions in domestic animals has substantial potential to enhance their welfare and productivity. Analysis of such behaviours in farrowing sows can highlight the need for human intervention or lead to the prediction of movement patterns that are potentially dangerous for their piglets, such as crushing when the sow lies down. Data were recorded by a tri-axial accelerometer secured to the hind-end of each sow, in a deployment that involved six sows over the period around parturition. The posture state (standing, sitting, lateral and sternal lying) was automatically classified for the full dataset with a mean F1 score (a measure of predictive performance between 0 and 1) of 0.78. Sitting was shown to present a greater challenge to classification with a F1 score of 0.54, compared to the lateral lying postures, which were classified with an average F1 score of 0.91. Posture transitions were detected with a F1 score of 0.79. We automatically extracted and visualized a range of features that characterise the manner in which the sows changed posture in order to provide comparative descriptors of sow activity and lying style that can be used to assess the influence of genetics or housing design. The methodology presented in this paper can be applied in large scale deployments with potential for enhancing animal welfare and productivity on farm.

Unsupervised home monitoring of Parkinson's disease motor symptoms using body-worn accelerometers

Fisher, J.M., Hammerla, N.Y., Ploetz, T., Andras, P., Rochester, L. and Walker, R.W.

Parkinsonism & Related Disorders 33 (2016)

Abstract: Introduction: Current PD assessment methods have inherent limitations. There is need for an objective method to assist clinical decisions and to facilitate evaluation of treatments. Accelerometers, and analysis using artificial neural networks (ANN), have shown potential as a method of motor symptom... Introduction: Current PD assessment methods have inherent limitations. There is need for an objective method to assist clinical decisions and to facilitate evaluation of treatments. Accelerometers, and analysis using artificial neural networks (ANN), have shown potential as a method of motor symptom evaluation. This work describes the development of a novel PD disease state detection system informed by algorithms based on data collected in an unsupervised, home environment. We evaluated whether this approach can reproduce patient-completed symptom diaries and clinical assessment of disease state. Methods: 34 participants with PD wore bilateral wrist-worn accelerometers for 4 h in a research facility (phase 1) and for 7 days at home whilst completing symptom diaries (phase 2). An ANN to predict disease state was developed based on home-derived accelerometer data. Using a leave-one-out approach, ANN performance was evaluated against patient-completed symptom diaries and against clinician rating of disease state. Results: In the clinical setting, specificity for dyskinesia detection was extremely high (0.99); high specificity was also demonstrated for home-derived data (0.93), but with low sensitivity (0.38). In both settings, sensitivity for on/off detection was sub-optimal. ANN-derived values of the proportions of time in each disease state showed strong, significant correlations with patient-completed symptom diaries. Conclusion: Accurate, real-time evaluation of symptoms in an unsupervised, home environment, with this sensor system, is not yet achievable. In terms of the amounts of time spent in each disease state, ANN-derived results were comparable to those of symptom diaries, suggesting this method may provide a valuable outcome measure for medication trials.

Vision, visuo-cognition and postural control in Parkinson's disease: An associative pilot study

Hill, E., Stuart, S., Lord, S., Del Din, S. and Rochester, L.

Gait & Posture 48 (2016)

Abstract: Introduction: Impaired postural control (PC) is common in patients with Parkinson's disease (PD) and is a major contributor to falls, with significant consequences. Mechanisms underpinning PC are complex and include motor and non-motor features. Research has focused predominantly on motor and sensor... Introduction: Impaired postural control (PC) is common in patients with Parkinson's disease (PD) and is a major contributor to falls, with significant consequences. Mechanisms underpinning PC are complex and include motor and non-motor features. Research has focused predominantly on motor and sensory inputs. Vision and visuo-cognitive function are also integral to PC but have largely been ignored to date. The aim of this observational cross-sectional pilot study was to explore the relationship of vision and visuo-cognition with PC in PD. Methods: Twelve people with PD and ten age-matched healthy controls (HC) underwent detailed assessments for vision, visuo-cognition and postural control. Vision assessments included visual acuity and contrast sensitivity. Visuo-cognition was measured by visuo-perception (object identification), visuo-construction (ability to copy a figure) and visuo-spatial ability (judge distances and location of object within environment). PC was measured by an accelerometer for a range of outcomes during a 2-min static stance. Spearman's correlations identified significant associations. Results: Contrast sensitivity, visuo-spatial ability and postural control (ellipsis) were significantly impaired in PD (p = 0.017; p = 0.001; and p = 0.017, respectively). For PD only, significant correlations were found for higher visuo-spatial function and larger ellipsis (r = 0.64; p = 0.024) and impaired attention and reduced visuo-spatial function (r = −0.62; p = 0.028). Conclusions: Visuo-spatial ability is associated with PC deficit in PD, but in an unexpected direction. This suggests a non-linear pattern of response. Further research is required to examine this novel and important finding.

Validation of an accelerometer to quantify a comprehensive battery of gait characteristics in healthy older adults and Parkinson's disease: toward clinical and at home use

Del Din, S., Godfrey, A. and Rochester, L.

IEEE journal of biomedical and health informatics 20.3 (2016)

Abstract: Measurement of gait is becoming important as a tool to identify disease and disease progression, yet to date its application is limited largely to specialist centers. Wearable devices enables gait to be measured in naturalistic environments, however questions remain regarding validity. Previous rese... Measurement of gait is becoming important as a tool to identify disease and disease progression, yet to date its application is limited largely to specialist centers. Wearable devices enables gait to be measured in naturalistic environments, however questions remain regarding validity. Previous research suggests that when compared with a laboratory reference, measurement accuracy is acceptable for mean but not variability or asymmetry gait characteristics. Some fundamental reasons for this have been presented, (e.g., synchronization, different sampling frequencies) but to date this has not been systematically examined. The aims of this study were to: 1) quantify a comprehensive range of gait characteristics measured using a single triaxial accelerometer-based monitor; 2) examine outcomes and monitor performance in measuring gait in older adults and those with Parkinson's disease (PD); and 3) carry out a detailed comparison with those derived from an instrumented walkway to account for any discrepancies. Fourteen gait characteristics were quantified in 30 people with incident PD and 30 healthy age-matched controls. Of the 14 gait characteristics compared, agreement between instruments was excellent for four (ICCs 0.913-0.983); moderate for four (ICCs 0.508-0.766); and poor for six characteristics (ICCs 0.637-0.370). Further analysis revealed that differences reflect an increased sensitivity of accelerometry to detect motion, rather than measurement error. This is most likely because accelerometry measures gait as a continuous activity rather than discrete footfall events, per instrumented tools. The increased sensitivity shown for these characteristics will be of particular interest to researchers keen to interpret “real-world” gait data. In conclusion, use of a body-worn monitor is recommended for the measurement of gait but is likely to yield more sensitive data for asymmetry and variability features.

An investigation of the orthogonal outputs from an on-rotor MEMS accelerometer for reciprocating compressor condition monitoring

Feng, G., Hu, N., Mones, Z., Gu, F. and Ball, A.D.

Mechanical Systems and Signal Processing 76 (2016)

Abstract: With rapid development in electronics and microelectromechanical systems (MEMS) technology, it becomes possible and attractive to monitor rotor dynamics by directly installing MEMS accelerometers on rotors. This paper studies the mathematical modelling of the orthogonal outputs from an on-rotor MEMS... With rapid development in electronics and microelectromechanical systems (MEMS) technology, it becomes possible and attractive to monitor rotor dynamics by directly installing MEMS accelerometers on rotors. This paper studies the mathematical modelling of the orthogonal outputs from an on-rotor MEMS accelerometer and proposes a method to eliminate the gravitational acceleration projected on the measurement axes. This is achieved by shifting the output in the normal direction by π/2 using a Hilbert transform and then combining it with the output of the tangential direction. With further compensation of the combined signal in the frequency domain, the tangential acceleration of the rotor is reconstructed to a high degree of accuracy. Experimental results show that the crankshaft tangential acceleration of a reciprocating compressor, obtained by the proposed method, can discriminate clearly between different discharge pressures and hence can allow common leakage faults to be detected, located and diagnosed for online condition monitoring purposes.

Free-living gait characteristics in ageing and Parkinson's disease: impact of environment and ambulatory bout length

Del Din, S., Godfrey, A., Galna, B., Lord, S. and Rochester, L.

Journal of neuroengineering and rehabilitation 13.1 (2016)

Abstract: Background: Gait is emerging as a powerful diagnostic and prognostic tool, and as a surrogate marker of disease progression for Parkinson’s disease (PD). Accelerometer-based body worn monitors (BWMs) facilitate the measurement of gait in clinical environments. Moreover they have the potential to p... Background: Gait is emerging as a powerful diagnostic and prognostic tool, and as a surrogate marker of disease progression for Parkinson’s disease (PD). Accelerometer-based body worn monitors (BWMs) facilitate the measurement of gait in clinical environments. Moreover they have the potential to provide a more accurate reflection of gait in the home during habitual behaviours. Emerging research suggests that measurement of gait using BWMs is feasible but this has not been investigated in depth. The aims of this study were to explore (i) the impact of environment and (ii) ambulatory bout (AB) length on gait characteristics for discriminating between people with PD and age-matched controls. Methods: Fourteen clinically relevant gait characteristics organised in five domains (pace, variability, rhythm, asymmetry, postural control) were quantified using laboratory based and free-living data collected over 7 days using a BWM placed on the lower back in 47 PD participants and 50 controls. Results: Free-living data showed that both groups walked with decreased pace and increased variability, rhythm and asymmetry compared to walking in the laboratory setting. Four of the 14 gait characteristics measured in free-living conditions were significantly different between controls and people with PD compared to two measured in the laboratory. Between group differences depended on bout length and were more apparent during longer ABs. ABs ≤ 10s did not discriminate between groups. Medium to long ABs highlighted between-group significant differences for pace, rhythm and asymmetry. Longer ABs should therefore be taken into account when evaluating gait characteristics in free-living conditions. Conclusion: This study provides encouraging results to support the use of a single BWM for free-living gait evaluation in people with PD with potential for research and clinical application.

Validation of algorithms for physical activity type detection in children using raw acceleration data

Ustad, A.

MS thesis. NTNU (2016)

Abstract: Background: Accelerometry has become the objective method of choice to assess physical activity in children. However a number of limitations are related to how accelerometer data from children are analyzed. Valid algorithms to classify accelerometer data into physical activity types can enhance our ... Background: Accelerometry has become the objective method of choice to assess physical activity in children. However a number of limitations are related to how accelerometer data from children are analyzed. Valid algorithms to classify accelerometer data into physical activity types can enhance our understanding of children's physical behavior and provide useful information of different aspects of physical activity. Aim: The aim of this study was to examine the validity of three algorithms for physical activity type detection in children using raw accelerometer data. The physical activity types of interest were the everyday activities walking, running, stair walking, cycling, standing, sitting and lying. Methods: 15 typically developing children (7 boys and 8 girls) in the age range between 6 and 12 years conducted several repetitions of the everyday activities of interest while they wore accelerometers (Axivity AX3) on lower back and mid-thigh and were video recorded. The videos were labeled and used as gold standard for validation of the physical activity types identified by the algorithms. Three algorithms were evaluated: the Acti4 algorithm and the NTNU-adults algorithm, which were developed on data from adults, and the NTNU-children algorithm that was developed based on the children data from this study. Results: The overall accuracy was 84.5%, 63.6% and 70.6% for the NTNU-children algorithm, the NTNU-adults algorithm and the Acti4 algorithm, respectively. The children algorithm showed consistently higher sensitivity, specificity and positive predictive values than the two adults algorithms. Sensitivity for the children algorithm was >0.89 for all activities of interest except stair walking (0.57-0.73). The NTNU-adults algorithm had very low sensitivity for walking, stair walking and cycling (<0.56) and high sensitivity for standing, sitting, lying and running (0.78-0.88). The Acti4 algorithm showed high sensitivity for walking, stair walking, running, cycling and lying (0.81-1.00), and lower sensitivity for standing (0.73) and sitting (0.66). Conclusion: The children algorithm showed higher overall accuracy than the adults algorithms and detected the activities walking, running, cycling, standing, sitting and lying with very high precision in children. The results indicate that children-specific algorithms are necessary. This study showed that raw acceleration data from two monitors placed on lower back and mid-thigh can be used to detect and separate the static activities standing, sitting and lying, and detect the dynamic activities walking, running and cycling, with high precision in children.

A multi-resolution investigation for postural transition detection and quantification using a single wearable

Hickey, A., Galna, B., Mathers, J.C., Rochester, L. and Godfrey, A.

Gait & Posture 49 (2016)

Abstract: Background: Multi-resolution analyses involving wavelets are commonly applied to data derived from accelerometer-based wearable technologies (wearables) to identify and quantify postural transitions (PTs). Previous studies fail to provide rationale to inform their choice of wavelet and scale approxi... Background: Multi-resolution analyses involving wavelets are commonly applied to data derived from accelerometer-based wearable technologies (wearables) to identify and quantify postural transitions (PTs). Previous studies fail to provide rationale to inform their choice of wavelet and scale approximation when utilising discrete wavelet transforms. This study examines varying combinations of those parameters to identify best practice recommendations for detecting and quantifying sit-to-stand (SiSt) and stand-to-sit (StSi) PTs. Methods: 39 young and 37 older participants completed three SiSt and StSi PTs on supported and unsupported chair types while wearing a single tri-axial accelerometer-based wearable on the lower back. Transition detection and duration were calculated through peak detection within the signal vector magnitude for a range of wavelets and scale approximations. A laboratory reference measure (2D video) was used for comparative analysis. Results: Detection accuracy of wavelet and scale combinations for the transitions was excellent for both SiSt (87–97%) and StSi (82–86%) PT-types. The duration of PTs derived from the wearable showed considerable bias and poor agreement compared with the reference videos. No differences were observed between chair types and age groups respectively. Conclusions: Improved detection of PTs could be achieved through the incorporation of different wavelet and scale combinations for the assessment of specific PT types in clinical and free-living settings. An upper threshold of 5th scale approximations is advocated for improved detection of multiple PT-types. However, care should be taken estimating the duration of PTs using wearables.

Accuracy and re-test reliability of mobile eye-tracking in Parkinson's disease and older adults

Stuart, S., Alcock, L., Godfrey, A., Lord, S., Rochester, L. and Galna, B.

Medical engineering & physics 38.3 (2016)

Abstract: Mobile eye-tracking is important for understanding the role of vision during real-world tasks in older adults (OA) and people with Parkinson's disease (PD). However, accuracy and reliability of such devices have not been established in these populations. We used a novel protocol to quantify accuracy... Mobile eye-tracking is important for understanding the role of vision during real-world tasks in older adults (OA) and people with Parkinson's disease (PD). However, accuracy and reliability of such devices have not been established in these populations. We used a novel protocol to quantify accuracy and reliability of a mobile eye-tracker in OA and PD. A mobile eye-tracker (Dikablis) measured the saccade amplitudes of 20 OA and 14 PD on two occasions. Participants made saccades between targets placed 5°, 10° and 15° apart. Impact of visual correction (glasses) on saccadic amplitude measurement was also investigated in 10 OA. Saccade amplitude accuracy (median bias) was −1.21° but a wide range of bias (−7.73° to 5.81°) was seen in OA and PD, with large vertical saccades (15°) being least accurate. Reliability assessment showed a median difference between sessions of <1° for both groups, with poor to good relative agreement (Spearman rho: 0.14 to 0.85). Greater accuracy and reliability was observed in people without visual correction. Saccade amplitude can be measured with variable accuracy and reliability using a mobile eye-tracker in OA and PD. Human, technological and study-specific protocol factors may introduce error and are discussed along with methodological recommendations.

Validation of the AX3 triaxial accelerometer in older functionally impaired people

Clarke, C.L., Taylor, J., Crighton, L.J., Goodbrand, J.A., McMurdo, M.E. and Witham, M.D.

Aging Clinical and Experimental Research (2016)

Abstract: Background: Studying physical activity (PA) trends in older populations and potential interventions for increasing PA is important, as PA is a factor in many age-related health outcomes such as chronic disease, premature mortality, physical function and injuries from falls. Objective measures of PA ... Background: Studying physical activity (PA) trends in older populations and potential interventions for increasing PA is important, as PA is a factor in many age-related health outcomes such as chronic disease, premature mortality, physical function and injuries from falls. Objective measures of PA provide valuable information regarding the functional impact that ageing and chronic disease states may have on a patient’s life. Aims: The purpose of this study was to test the validity of the AX3 PA monitor in an older population and to investigate whether the AX3 is a valid measure of distinct types or levels of activity in older people with a spectrum of mobility. Methods: Validity of the AX3 PA monitor was tested using the RT3 as a means of cross-validating the AX3. Study participants wore both the AX3 and the RT3 accelerometers, positioned on their non-dominant side, whilst completing a series of standardised everyday activities. Results: Although overall correlation was high (r > 0.8) between the RT3 and lower-limb-mounted AX3 counts, the correlation between the two devices was much stronger for walking activity than for any of the non-walking activities. Discussion: Activity counts at all lower limb positions for the AX3 and RT3 were highly correlated. Correlation between wrist-mounted AX3 counts and lower limb AX3 counts was only moderate, and worsened when walking aids were in use. Conclusions: The results of this study indicate that the AX3 monitor is a valid tool, which might be used to objectively measure walking activity in older functionally impaired adults, a welcome finding for this under-researched area.

A comparison between three activity monitors in detecting commonly performed activities and postures of daily living

Hada, S., Kinoshita, M., Shiozawa, J., Takazawa, Y. and Ikeda, H.

Abstracts/Osteoarthritis and Cartilage 24.S63eS534 (2016)

Abstract: Knee osteoarthritis (KOA) is regarded as the foremost cause offunctional limitations during daily life in elderly, such as difficulty instair climbing. Being able to accurately monitor KOA patients’ activityduring daily life could provide valuable information. Currently usedactivity monitors (AM) ... Knee osteoarthritis (KOA) is regarded as the foremost cause offunctional limitations during daily life in elderly, such as difficulty instair climbing. Being able to accurately monitor KOA patients’ activityduring daily life could provide valuable information. Currently usedactivity monitors (AM) are only able to detect stepping and sedentarybehaviour. Therefore, the aim of this study was to analyse whether anewly developed activity monitor can accurately classify additionalactivities and to compare its accuracy versus two established devices.

Detecting free-living steps and walking bouts: validating an algorithm for macro gait analysis

Hickey, A., Del Din, S., Rochester, L. and Godfrey, A.

Physiological Measurement 38.1 (2016)

Abstract: Research suggests wearables and not instrumented walkways are better suited to quantify gait outcomes in clinic and free-living environments, providing a more comprehensive overview of walking due to continuous monitoring. Numerous validation studies in controlled settings exist, but few have examin... Research suggests wearables and not instrumented walkways are better suited to quantify gait outcomes in clinic and free-living environments, providing a more comprehensive overview of walking due to continuous monitoring. Numerous validation studies in controlled settings exist, but few have examined the validity of wearables and associated algorithms for identifying and quantifying step counts and walking bouts in uncontrolled (free-living) environments. Studies which have examined free-living step and bout count validity found limited agreement due to variations in walking speed, changing terrain or task. Here we present a gait segmentation algorithm to define free-living step count and walking bouts from an open-source, high-resolution, accelerometer-based wearable (AX3, Axivity). Ten healthy participants (20–33 years) wore two portable gait measurement systems; a wearable accelerometer on the lower-back and a wearable body-mounted camera (GoPro HERO) on the chest, for 1 h on two separate occasions (24 h apart) during free-living activities. Step count and walking bouts were derived for both measurement systems and compared. For all participants during a total of almost 20 h of uncontrolled and unscripted free-living activity data, excellent relative (rho  ≥  0.941) and absolute (ICC(2,1)  ≥  0.975) agreement with no presence of bias were identified for step count compared to the camera (gold standard reference). Walking bout identification showed excellent relative (rho  ≥  0.909) and absolute agreement (ICC(2,1)  ≥  0.941) but demonstrated significant bias. The algorithm employed for identifying and quantifying steps and bouts from a single wearable accelerometer worn on the lower-back has been demonstrated to be valid and could be used for pragmatic gait analysis in prolonged uncontrolled free-living environments.

Mitochondrial capacity, muscle endurance & low energy in friedreich ataxia

Bossie, H., Willingham, T.B., Van Schoick, R., O'Connor, P. and McCully, K.

Muscle & Nerve (2016)

Abstract: INTRODUCTION: We noninvasively evaluated skeletal muscle mitochondrial capacity, muscle-specific endurance, and energy/fatigue feelings in persons with Friedreich ataxia (FRDA) and able-bodied controls (AB). METHODS: Forearm mitochondrial capacity was measured in FRDA (n=16) and AB (n=10) using the ... INTRODUCTION: We noninvasively evaluated skeletal muscle mitochondrial capacity, muscle-specific endurance, and energy/fatigue feelings in persons with Friedreich ataxia (FRDA) and able-bodied controls (AB). METHODS: Forearm mitochondrial capacity was measured in FRDA (n=16) and AB (n=10) using the rate of recovery of oxygen consumption after electrical stimulation with near-infrared spectroscopy. Mechanomyography (MMG) assessed muscle endurance after electrical stimulation for 3-minutes at 2Hz, 4Hz, and 6Hz. Validated scales assessed disease severity and energy/fatigue feelings. RESULTS: Groups did not differ in mitochondrial capacity (FRDA and AB: 1.8?±?0.3 1/min). The difference in muscle endurance at 6 Hz was lower by 19.2% in the FRDA (group affect: P < 0.001). Feelings of physical energy were 34% lower in FRDA. In FDRA muscle, endurance was positively related to mitochondrial capacity (r=0.59, P=0.03), and disease severity was negatively related to mitochondrial capacity (r=-0.55, P=0.04) and muscle endurance (r=-0.60, P=0.01). DISCUSSION: Non-invasive measures of skeletal muscle mitochondrial capacity and muscle specific endurance are useful in monitoring FRDA. This article is protected by copyright. All rights reserved.

Time-dependent changes in postural control in early Parkinson's disease: what are we missing?

Del Din, S., Godfrey, A., Coleman, S., Galna, B., Lord, S. and Rochester, L.

Medical & biological engineering & computing 54.2-3 (2016)

Abstract: Impaired postural control (PC) is an important feature of Parkinson’s disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, ... Impaired postural control (PC) is an important feature of Parkinson’s disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, and identified outcomes most sensitive to pathology. Thirty-one controls and 26 PD patients were recruited: PC was measured with an accelerometer on the lower back for 2 minutes (mins). Preliminary analysis (autocorrelation) that showed 2 seconds (s) was the shortest duration sensitive to changes in the signal; time series analysis of a range of PC outcomes was undertaken using consecutive 2-s windows over the test. Piecewise linear regression was used to fit the time series data during the first 30 s and the subsequent 90 s of the trial. PC outcomes changed over the 2 mins, with the greatest change observed during the first 30 s after which PC stabilised. Changes in PC were reduced in PD compared to controls, and Jerk was found to be discriminative of pathology. Previous studies focusing on average performance over the duration of a test may miss time-dependent differences. Evaluation of time-dependent change may provide useful insights into PC in PD and effectiveness of intervention.

Everyday household practices and electricity use: Early findings from a mixed-method approach to assessign demand flexibility

Topouzi, M., Grunewald, P., Gershuny, J. and Harms, T.

4th European Conference on Behaviour and Energy Efficiency (2016)

Abstract: In managing the high electrical energy demand during the peak early evening hours in UK domestic buildings it is critical to understand how household practices are coordinated in relation to resources used. In this paper an interdisciplinary group of researchers from sociology, environmental science... In managing the high electrical energy demand during the peak early evening hours in UK domestic buildings it is critical to understand how household practices are coordinated in relation to resources used. In this paper an interdisciplinary group of researchers from sociology, environmental science, engineering and health present an account of their methodological approach and the reasoning behind it, along with some evidence of the impact different household everyday activities and routines have on electricity demand. It presents an innovative methodological approach that brings together Time-use and Energy-use research in households by combining social science and engineering tools and techniques in data collection and analysis. Established methods of self-report Time Use dairies and structured questionnaires were combined with innovative high-resolution electricity meters, automated Wearable cameras, and wrist-worn accelerometers capturing both qualitative and quantitative data. Electricity use was explored in this study through the lens of the temporal sequence of everyday activities that occur at home - often synchronised with other activities (or events) - and involving a number of appliances. The analysis of different variants related to time, space, sequence and intensity of activities showed how the extended routines involved in practices like food preparation, eating, personal/family care, household upkeep and resting/leisure time, might be flexible in time to adapt to electricity network requirements. Insights from this study provide indicators of the flexibility (or inflexibility) everyday household practices have which can be scaled-up and explored in larger datasets

A multi-modal architecture for non-intrusive analysis of performance in the workplace

Carneiro, D., Pimenta, A., Neves, J. and Novais, P.

Neurocomputing (2016)

Abstract: Human performance, in all its different dimensions, is a very complex and interesting topic. In this paper we focus on performance in the workplace which, asides from complex is often controversial. While organizations and generally competitive working conditions push workers into increasing perform... Human performance, in all its different dimensions, is a very complex and interesting topic. In this paper we focus on performance in the workplace which, asides from complex is often controversial. While organizations and generally competitive working conditions push workers into increasing performance demands, this does not necessarily correlates positively to productivity. Moreover, existing performance monitoring approaches (electronic or not) are often dreaded by workers since they either threat their privacy or are based on productivity measures, with specific side effects. We present a new approach for the problem of performance monitoring that is not based on productivity measures but on the workers' movements while sitting and on the performance of their interaction with the machine. We show that these features correlate with mental fatigue and provide a distributed architecture for the non-intrusive and transparent collection of this data. The easiness in deploying this architecture, its non-intrusive nature, the potential advantages for better human resources management and the fact that it is not based on productivity measures will, in our belief, increase the willingness of both organizations and workers to implement this kind of performance management initiatives.

Towards holistic free-living assessment in Parkinson's disease: Unification of gait and fall algorithms with a single accelerometer

Godfrey, A., Bourke, A., Del Din, S., Morris, R., Hickey, A., Helbostad, J.L. and Rochester, L.

Engineering in Medicine and Biology Society (EMBC), IEEE (2016)

Abstract: Technological developments have seen the miniaturization of sensors, small enough to be embedded in wearable devices facilitating unobtrusive and longitudinal monitoring in free-living environments. Concurrently, the advances in algorithms have been ad-hoc and fragmented. To advance the mainstream u... Technological developments have seen the miniaturization of sensors, small enough to be embedded in wearable devices facilitating unobtrusive and longitudinal monitoring in free-living environments. Concurrently, the advances in algorithms have been ad-hoc and fragmented. To advance the mainstream use of wearable technology and improved functionality of algorithms all methodologies must be unified and robustly tested within controlled and free-living conditions. Here we present and unify a (i) gait segmentation and analysis algorithm and (ii) a fall detection algorithm. We tested the unified algorithms on a cohort of young healthy adults within a laboratory. We then deployed the algorithms on longitudinal (7 day) accelerometer-based data from an older adult with Parkinson's disease (PD) to quantify real world gait and falls. We compared instrumented falls to a self-reported falls diary to test algorithm efficiency and discuss the use of unified algorithms to impact free-living assessment in PD where accurate recognition of gait may reduce the number of automated detected falls (38/week). This informs ongoing work to use gait and related outcomes as pragmatic clinical markers.

Instrumented gait assessment with a single wearable: an introductory tutorial

Del Din, S., Hickey, A., Ladha, C., Stuart, S., Bourke, A.K., Esser, P., Rochester, L. and Godfrey, A.

F1000Research 5 (2016)

Abstract: Background: Gait is a powerful tool to identify ageing and track disease progression. Yet, its high resolution measurement via traditional instruments remains restricted to the laboratory or bespoke clinical facilities. The potential for that to change is due to the advances in wearables where the s... Background: Gait is a powerful tool to identify ageing and track disease progression. Yet, its high resolution measurement via traditional instruments remains restricted to the laboratory or bespoke clinical facilities. The potential for that to change is due to the advances in wearables where the synergy between devices and smart algorithms has provided the potential of ‘a gait lab on a chip’. Methods: Commercially available wearables for gait quantification remain expensive and are restricted to a limited number of characteristics unsuitable for a comprehensive assessment required within intervention or epidemiological studies. However, the increasing demand for low-cost diagnostics has fuelled the shift in how health-related resources are distributed. As such we adopt open platform technology and validated research methodologies to harmonise engineering solutions to satisfy current epidemiological needs. Results: We provide an introduction to conduct a routine instrumented gait assessment with a discrete, low-cost, accelerometer-based wearable. We show that the capture and interpretation of raw gait signals with a common scripting language can be straightforward and suitable for use within modern studies. We highlight the best approaches and hope that this will help compliment any analytical tool-kit as part of future cohort assessments. Conclusions: Deployment of wearables can allow accurate gait assessment in accordance with advocated methods of data collection as there is a strong demand for sensitive outcomes derived from pragmatic tools. This tutorial shows that instrumentation of gait using a single open source wearable is pragmatic due to low-cost and translational analytical methods to derive sensitive outcomes.

Free-living monitoring of Parkinson's disease: Lessons from the field

Del Din, S., Godfrey, A., Mazzà, C., Lord, S. and Rochester, L.

Movement Disorders 31.9 (2016)

Abstract: Wearable technology comprises miniaturized sensors (eg, accelerometers) worn on the body and/or paired with mobile devices (eg, smart phones) allowing continuous patient monitoring in unsupervised, habitual environments (termed free-living). Wearable technologies are revolutionizing approaches to he... Wearable technology comprises miniaturized sensors (eg, accelerometers) worn on the body and/or paired with mobile devices (eg, smart phones) allowing continuous patient monitoring in unsupervised, habitual environments (termed free-living). Wearable technologies are revolutionizing approaches to health care as a result of their utility, accessibility, and affordability. They are positioned to transform Parkinson's disease (PD) management through the provision of individualized, comprehensive, and representative data. This is particularly relevant in PD where symptoms are often triggered by task and free-living environmental challenges that cannot be replicated with sufficient veracity elsewhere. This review concerns use of wearable technology in free-living environments for people with PD. It outlines the potential advantages of wearable technologies and evidence for these to accurately detect and measure clinically relevant features including motor symptoms, falls risk, freezing of gait, gait, functional mobility, and physical activity. Technological limitations and challenges are highlighted, and advances concerning broader aspects are discussed. Recommendations to overcome key challenges are made. To date there is no fully validated system to monitor clinical features or activities in free-living environments. Robust accuracy and validity metrics for some features have been reported, and wearable technology may be used in these cases with a degree of confidence. Utility and acceptability appears reasonable, although testing has largely been informal. Key recommendations include adopting a multidisciplinary approach for standardizing definitions, protocols, and outcomes. Robust validation of developed algorithms and sensor-based metrics is required along with testing of utility. These advances are required before widespread clinical adoption of wearable technology can be realized. © 2016 International Parkinson and Movement Disorder Society

Detection of physical activity types with accelerometers in adolescents during semi-structured free-living

Bårdstu, H.B.

MS thesis. NTNU, (2016)

Abstract: Background Few algorithms are available for detection and classification of physical activity (PA) types in adolescents, and existing algorithms are only validated in controlled laboratory settings. The performance of such algorithms outside of the laboratory in adolescents remains unexplored. Sever... Background Few algorithms are available for detection and classification of physical activity (PA) types in adolescents, and existing algorithms are only validated in controlled laboratory settings. The performance of such algorithms outside of the laboratory in adolescents remains unexplored. Several algorithms have been developed and validated for adults but it is uncertain if these algorithms are valid for detection and classification of PA in adolescents. Aim The aim of this study was to evaluate the validity of an algorithm developed for detection of PA in adolescents (NTNUADOL). A comparison was made against the performance of an algorithm developed for detection of PA in adults (NTNUADUL). The evaluation of the validity was based on the algorithms performance in detecting PA types in adolescent during semi-structured free-living. Methods Twelve adolescents (6 boys, 6 girls, mean age 14.7 years, range 13-16 years) were equipped with two accelerometers (Axivity AX3) and a chest-mounted camera. A semi-structured free-living session for detection of PA types was carried out. Video recordings were used as validation criterion, and PA types were defined and used as guidelines for annotation of the video-recordings. Two algorithms, NTNUADOL and NTNUADUL, were developed and used for analysis. To test the performance of the NTNU-algorithms a reference was made against an existing algorithm developed for adults (Acti4) in a separate analysis. Walking, standing, sitting, lying down, shuffling, walking stairs, running and other vigorous PA was analyzed. Overall accuracy was calculated for each algorithm. Sensitivity, specificity and accuracy were calculated for each PA type. Confusion matrices were included to show the distribution of correctly and incorrectly classified instances. Results Overall accuracy was 87% for NTNUADOL and 85% for NTNUADUL. Both algorithms could detect walking, standing, sitting, lying down and running with sensitivity above 80%. Specificity and accuracy was high (>87%) for both algorithms. The NTNUADOL showed highest sensitivity for detection of walking, standing, sitting, lying down, running, walking stairs up and other vigorous PA, while NTNUADUL showed higher sensitivity for shuffling and walking stairs down. Most misclassifications were due to insufficient discrimination between shuffling, walking and standing, and between walking stairs and horizontal walking Conclusion Both algorithms were able to detect walking, sitting, standing, lying down and running with acceptable to high performance. There were no major differences between the algorithms. The most evident differences were found for detection of other vigorous PA with the NTNUADOL being superior and shuffling with the NTNUADUL being superior.

Wristband Accelerometers to motiVate arm Exercise after Stroke (WAVES): study protocol for a pilot randomized controlled trial

Moore, S.A., Da Silva, R., Balaam, M., Brkic, L., Jackson, D., Jamieson, D., Ploetz, T., Rodgers, H., Shaw, L., Van Wijck, F. and Price, C.

Trials 17.1 (2016)

Abstract: Background: Loss of upper limb function affects up to 85 % of acute stroke patients. Recovery of upper limb function requires regular intensive practise of specific upper limb tasks. To enhance intensity of practice interventions are being developed to encourage patients to undertake self-directed e... Background: Loss of upper limb function affects up to 85 % of acute stroke patients. Recovery of upper limb function requires regular intensive practise of specific upper limb tasks. To enhance intensity of practice interventions are being developed to encourage patients to undertake self-directed exercise practice. Most interventions do not translate well into everyday activities and stroke patients continue to find it difficult remembering integration of upper limb movements into daily activities. A wrist-worn device has been developed that monitors and provides ‘live’ upper limb activity feedback to remind patients to use their stroke arm in daily activities (The CueS wristband). The aim of this trial is to assess the feasibility of a multi-centre, observer blind, pilot randomised controlled trial of the CueS wristband in clinical stroke services. Methods/design: This pilot randomised controlled feasibility trial aims to recruit 60 participants over 15 months from North East England. Participants will be within 3 months of stroke which has caused new reduced upper limb function and will still be receiving therapy. Each participant will be randomised to an intervention or control group. Intervention participants will wear a CueS wristband (between 8 am and 8 pm) providing “live” feedback towards pre-set movement goals through a simple visual display and vibration prompts whilst undertaking a 4-week upper limb therapy programme (reviewed twice weekly by an occupational/physiotherapist). Control participants will also complete the 4-week upper limb therapy programme but will wear a ‘sham’ CueS wristband that monitors upper limb activity but provides no feedback. Outcomes will determine study feasibility in terms of recruitment, retention, adverse events, adherence and collection of descriptive clinical and accelerometer motor performance data at baseline, 4 weeks and 8 weeks. Discussion: The WAVES study will address an important gap in the evidence base by reporting the feasibility of undertaking an evaluation of emerging and affordable technology to encourage impaired upper limb activity after stroke. The study will establish whether the study protocol can be supported by clinical stroke services, thereby informing the design of a future multi-centre randomised controlled trial of clinical and cost-effectiveness.

Pilot Randomised Controlled Trial of a Web-Based Intervention to Promote Healthy Eating, Physical Activity and Meaningful Social Connections Compared with Usual Care Control in People of Retirement Age Recruited from Workplaces

Lara, J., O’Brien, N., Godfrey, A., Heaven, B., Evans, E.H., Lloyd, S., Moffatt, S., Moynihan, P.J., Meyer, T.D., Rochester, L. and Sniehotta, F.F.

PLoS One 11.7 (2016)

Abstract: Background: Lifestyle interventions delivered during the retirement transition might promote healthier ageing. We report a pilot randomised controlled trial (RCT) of a web-based platform (Living, Eating, Activity and Planning through retirement; LEAP) promoting healthy eating (based on a Mediterrane... Background: Lifestyle interventions delivered during the retirement transition might promote healthier ageing. We report a pilot randomised controlled trial (RCT) of a web-based platform (Living, Eating, Activity and Planning through retirement; LEAP) promoting healthy eating (based on a Mediterranean diet (MD)), physical activity (PA) and meaningful social roles. Methods: A single blinded, two-arm RCT with individual allocation. Seventy-five adult regular internet users living in Northeast England, within two years of retirement, were recruited via employers and randomised in a 2:1 ratio to receive LEAP or a ‘usual care’ control. Intervention arm participants were provided with a pedometer to encourage self-monitoring of PA goals. Feasibility of the trial design and procedures was established by estimating recruitment and retention rates, and of LEAP from usage data. At baseline and 8-week follow-up, adherence to a MD derived from three 24-hour dietary recalls and seven-day PA by accelerometry were assessed. Healthy ageing outcomes (including measures of physiological function, physical capability, cognition, psychological and social wellbeing) were assessed and acceptability established by compliance with measurement protocols and completion rates. Thematically analysed, semi-structured, qualitative interviews assessed acceptability of the intervention, trial design, procedures and outcome measures. Results: Seventy participants completed the trial; 48 (96%) participants in the intervention and 22 (88%) in the control arm. Participants had considerable scope for improvement in diet as assessed by MD score. LEAP was visited a median of 11 times (range 1–80) for a mean total time of 2.5 hours (range 5.5 min– 8.3 hours). ‘Moving more‘, ‘eating well’ and ‘being social’ were the most visited modules. At interview, participants reported that diet and PA modules were important and acceptable within the context of healthy ageing. Participants found both trial procedures and outcome assessments acceptable. Conclusions: The trial procedures and the LEAP intervention proved feasible and acceptable. Effectiveness and cost-effectiveness of LEAP to promote healthy lifestyles warrant evaluation in a definitive RCT.

Expressy: Using a Wrist-worn Inertial Measurement Unit to Add Expressiveness to Touch-based Interactions

Wilkinson, G., Kharrufa, A., Hook, J., Pursglove, B., Wood, G., Haeuser, H., Hammerla, N.Y., Hodges, S. and Olivier, P.

Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems. ACM (2016)

Abstract: Expressiveness, which we define as the extent to which rich and complex intent can be conveyed through action, is a vital aspect of many human interactions. For instance, paint on canvas is said to be an expressive medium, because it affords the artist the ability to convey multifaceted emotional in... Expressiveness, which we define as the extent to which rich and complex intent can be conveyed through action, is a vital aspect of many human interactions. For instance, paint on canvas is said to be an expressive medium, because it affords the artist the ability to convey multifaceted emotional intent through intricate manipulations of a brush. To date, touch devices have failed to offer users a level of expressiveness in their interactions that rivals that experienced by the painter and those completing other skilled physical tasks. We investigate how data about hand movement -- provided by a motion sensor, similar to those found in many smart watches or fitness trackers -- can be used to expand the expressiveness of touch interactions. We begin by introducing a conceptual model that formalizes a design space of possible expressive touch interactions. We then describe and evaluate Expressy, an approach that uses a wrist-worn inertial measurement unit to detect and classify qualities of touch interaction that extend beyond those offered by today's typical sensing hardware. We conclude by describing a number of sample applications, which demonstrate the enhanced, expressive interaction capabilities made possible by Expressy.

Sensing Technologies for Autism Spectrum Disorder Screening and Intervention

Cabibihan, J.J., Javed, H., Aldosari, M., Frazier, T.W. and Elbashir, H.

Sensors 17.1 (2016)

Abstract: This paper reviews the state-of-the-art in sensing technologies that are relevant for Autism Spectrum Disorder (ASD) screening and therapy. This disorder is characterized by difficulties in social communication, social interactions, and repetitive behaviors. It is diagnosed during the first three ye... This paper reviews the state-of-the-art in sensing technologies that are relevant for Autism Spectrum Disorder (ASD) screening and therapy. This disorder is characterized by difficulties in social communication, social interactions, and repetitive behaviors. It is diagnosed during the first three years of life. Early and intensive interventions have been shown to improve the developmental trajectory of the affected children. The earlier the diagnosis, the sooner the intervention therapy can begin, thus, making early diagnosis an important research goal. Technological innovations have tremendous potential to assist with early diagnosis and improve intervention programs. The need for careful and methodological evaluation of such emerging technologies becomes important in order to assist not only the therapists and clinicians in their selection of suitable tools, but to also guide the developers of the technologies in improving hardware and software. In this paper, we survey the literatures on sensing technologies for ASD and we categorize them into eye trackers, movement trackers, electrodermal activity monitors, tactile sensors, vocal prosody and speech detectors, and sleep quality assessment devices. We assess their effectiveness and study their limitations. We also examine the challenges faced by this growing field that need to be addressed before these technologies can perform up to their theoretical potential.

Current physical activity monitors in hip and knee osteoarthritis – A Review

Sliepen, M., Brandes, M. and Rosenbaum, D.

Arthritis Care & Research (2016)

Abstract: Objective: To provide an up-to-date overview of physical activity monitors that are being/have been used within hip and knee osteoarthritis research. Methods: A review was conducted to identify activity monitors used in hip and knee osteoarthritis research. In order to identify the relevant literatu... Objective: To provide an up-to-date overview of physical activity monitors that are being/have been used within hip and knee osteoarthritis research. Methods: A review was conducted to identify activity monitors used in hip and knee osteoarthritis research. In order to identify the relevant literature to-date, the MEDLINE (via Pubmed), EMBASE (via OVID) and SCOPUS databases were searched from January 2000 until January 2016. Per activity monitor, a broad range of specifications was identified by extracting information from the manufacturers' websites, device manuals and literature. Results: The initial search resulted in 369 articles, of which 181 were duplicates and an additional 70 articles were omitted for further analysis due to the in-/exclusion criteria. Finally, the search resulted in 118 eligible articles in which activity monitors were used. Fifteen different devices were identified from the articles. Their technical specifications and analytical options are presented in this review. Conclusions: This review provides a detailed list of currently available devices for physical activity monitoring with a broad spectrum of features, enabling the scientific community to select the most appropriate activity monitor, thereby hopefully improving the assessment of physical activity in hip and knee osteoarthritis researc This article is protected by copyright. All rights reserved.

Step Counting: A Review of Measurement Considerations and Health-Related Applications

Bassett, D.R., Toth, L.P., LaMunion, S.R. and Crouter, S.E.

Sports Medicine (2016)

Abstract: Step counting has long been used as a method of measuring distance. Starting in the mid-1900s, researchers became interested in using steps per day to quantify ambulatory physical activity. This line of research gained momentum after 1995, with the introduction of reasonably accurate spring-levered ... Step counting has long been used as a method of measuring distance. Starting in the mid-1900s, researchers became interested in using steps per day to quantify ambulatory physical activity. This line of research gained momentum after 1995, with the introduction of reasonably accurate spring-levered pedometers with digital displays. Since 2010, the use of accelerometer-based “activity trackers” by private citizens has skyrocketed. Steps have several advantages as a metric for assessing physical activity: they are intuitive, easy to measure, objective, and they represent a fundamental unit of human ambulatory activity. However, since they measure a human behavior, they have inherent biological variability; this means that measurements must be made over 3–7 days to attain valid and reliable estimates. There are many different kinds of step counters, designed to be worn on various sites on the body; all of these devices have strengths and limitations. In cross-sectional studies, strong associations between steps per day and health variables have been documented. Currently, at least eight prospective, longitudinal studies using accelerometers are being conducted that may help to establish dose–response relationships between steps/day and health outcomes. Longitudinal interventions using step counters have shown that they can help inactive individuals to increase by 2500 steps per day. Step counting is useful for surveillance, and studies have been conducted in a number of countries around the world. Future challenges include the need to establish testing protocols and accuracy standards, and to decide upon the best placement sites. These challenges should be addressed in order to achieve harmonization between studies, and to accurately quantify dose–response relationships.

The novel use of a SenseCam and accelerometer to validate training load and training information in a self-recall training diary

O. Connor, S., McCaffrey, N., Whyte, E. and Moran, K.

Journal of sports sciences 34.4 (2016)

Abstract: Self-recall training diaries are a frequently used tool to quantify training load and training information. While accelerometers are predominantly used to validate training diaries, they are unable to validate contextual training information. Thus this study aimed to examine the novel use of data fu... Self-recall training diaries are a frequently used tool to quantify training load and training information. While accelerometers are predominantly used to validate training diaries, they are unable to validate contextual training information. Thus this study aimed to examine the novel use of data fusion from a wearable camera device (SenseCam) and accelerometer to validate a self-recall training diary. Thirty participants filled in a training diary for 1 day while simultaneously wearing a SenseCam and accelerometer. The training diary was validated using Bland–Altman plots, Spearman’s rank-order correlation, percentage agreement and ? measure of agreement between the diary and the SenseCam and accelerometer. The results demonstrated overall agreement, and no bias, between the training diary and the accelerometer for training intensity, and the SenseCam for duration of activity and travel time. A positive correlation was found for duration (r = 0.82, P < 0.001) and intensity (r = 0.67, P < 0.001). Hundred per cent agreement was found between the SenseCam and training diary for activity, training surface and footwear (? = 1, P < 0.0001), with a lower agreement noted for sports played (97.3%, ? = 0.91, P < 0.0001). The self-recall training diary was found to be a valid measure of capturing training load and training information using the combined wearable camera device and accelerometer.

Human Activity Recognition With Two Body-Worn Accelerometer Sensors

Hessen, H.O. and Tessem, A.J.

Master's thesis, NTNU (2016)

Abstract: Data used in studies about physical activity is primarily collected from questionnaires and other subjective methods, which may lead to biased and inaccurate data. As subjective data collection methods have shown to be unreliable, enhancing or even replacing these methods with objective methods like... Data used in studies about physical activity is primarily collected from questionnaires and other subjective methods, which may lead to biased and inaccurate data. As subjective data collection methods have shown to be unreliable, enhancing or even replacing these methods with objective methods like the use of wearable technology and human activity recognition (HAR) systems, will lead to more accurate data. HAR systems are systems that can recognize what kind of activity a subject is performing based on the monitoring of data streams from sensors on, or close to, the subject. One way this can be achieved is by constructing a classification system that can recognize human activities from body-worn sensor readings. HUNT4 is an upcoming health study with about 60000 participants that will make use of objective measurements of their participants' physical activity to provide precise summaries about each participant's activity level. To be able to create these summaries, there is a need for a system that can recognize physical activities based on sensor readings. The main objective of our research is to design and construct such a HAR system. In this thesis, we have reviewed related work performed in the field of HAR, and identified potentials for further improvements of current HAR systems. We experimented with deep learning, semi-supervised learning, dynamic classification and dynamic windowing. Through an iterative process of adding and removing components, we propose a system that is able to distinguish between daily activities with a high level of precision. The final HAR system consists of a Convolutional Neural Network followed by a Hidden Markov model, reaching an accuracy for classifying activities of 97.9% for adults and 96.6% for adolescents.

Music-Dance. Investigating Rhythm Structures in Brazilian Samba and Norwegian Telespringar Performance

Haugen, M.R.

Phd Thesis (2016)

Abstract: This thesis investigates the interaction between perceived rhythm and underlying reference structures in the experience of rhythm in music. The point of departure is that both music performers’ and perceivers’ body motions are relevant to the study of rhythm. Accordingly, in music genres with an... This thesis investigates the interaction between perceived rhythm and underlying reference structures in the experience of rhythm in music. The point of departure is that both music performers’ and perceivers’ body motions are relevant to the study of rhythm. Accordingly, in music genres with an intimate relationship to dance, here referred to as music–dance, rhythm needs to be understood in relation to the corresponding dance. The studies included in this thesis investigate rhythm patterns in sound and body motion in two music–dance styles, Brazilian samba and Norwegian telespringar, based on motion capture and sound recordings of professional musicians and dancers. Both samba and telespringar consist of complex rhythm patterns. Samba is often characterized by so-called systematic microtiming at the sixteenth-note level. This was confirmed in our sound analysis of the samba groove, showing a medium–medium–medium–long duration pattern at the sixteenth-note level. In addition, motion analysis of the percussionist’s heel tapping and the dancer’s steps revealed motion patterns in synchrony with this rhythm pattern. Telespringar, on the other hand, is often described as featuring a so-called asymmetrical triple meter—that is, the three beats in a measure are of uneven duration. According to previous studies, both the fiddler’s foot stamping and the dancers’ vertical body motions are related to this underlying meter. This relation was confirmed in the motion analysis of a fiddler’s foot stamping, which revealed a very stable long–medium–short duration pattern at the beat level. The dancers’ vertical motion patterns, however, deviated from theories suggesting that the turning points in the dancers’ vertical motion curves correspond to the meter. The thesis therefore suggests an alternative interpretation with regard to the dancers’ vertical motion curves—that it is the shape of the dancers’ vertical motion that corresponds to the underlying beat duration, rather than the turning points that correspond to the underlying beat positions. The main conclusion is that the underlying sixteenth-note level in samba and the underlying beat level in telespringar should not be understood as deviations from an isochronous pulse of some sort. Instead, they should be understood as inherently (and necessarily) non-isochronous, in and of themselves.

Body-worn sensors in Parkinson's disease: evaluating their acceptability to patients

Fisher JM, Hammerla NY, Rochester L, Andras P, Walker RW.

Telemedicine and e-Health (2016)

Abstract: Background: Remote monitoring of symptoms in Parkinson's disease (PD) using body-worn sensors would assist treatment decisions and evaluation of new treatments. To date, a rigorous, systematic evaluation of the acceptability of body-worn sensors in PD has not been undertaken. Materials and Methods: ... Background: Remote monitoring of symptoms in Parkinson's disease (PD) using body-worn sensors would assist treatment decisions and evaluation of new treatments. To date, a rigorous, systematic evaluation of the acceptability of body-worn sensors in PD has not been undertaken. Materials and Methods: Thirty-four participants wore bilateral wrist-worn sensors for 4 h in a research facility and then for 1 week at home. Participants' experiences of wearing the sensors were evaluated using a Likert-style questionnaire after each phase. Qualitative data were collected through free-text responses. Differences in responses between phases were assessed by using the Wilcoxon rank-sum test. Content analysis of qualitative data was undertaken. “Non–wear time” was estimated via analysis of accelerometer data for periods when sensors were stationary. Results: After prolonged wearing there was a negative shift in participants' views on the comfort of the sensor; problems with the sensor's strap were highlighted. However, accelerometer data demonstrated high patient concordance with wearing of the sensors. There was no evidence that participants were less likely to wear the sensors in public. Most participants preferred wearing the sensors to completing symptom diaries. Conclusions: The finding that participants were not less likely to wear the sensors in public provides reassurance regarding the ecological validity of the data captured. The validity of our findings was strengthened by “triangulation” of data sources, enabling patients to express their agenda and repeated assessment after prolonged wearing. Long-term monitoring with wrist-worn sensors is acceptable to this cohort of PD patients. Evaluation of the wearer's experience is critical to the development of remote monitoring technology.

A comparison between three activity monitors in detecting commonly performed activities and postures of daily living

Sliepen M, Rosenbaum D.

Osteoarthritis and Cartilage (2016)

Abstract: Purpose: Knee osteoarthritis (KOA) is regarded as the foremost cause of functional limitations during daily life in elderly, such as difficulty in stair climbing. Being able to accurately monitor KOA patients’ activity during daily life could provide valuable information. Currently used activity m... Purpose: Knee osteoarthritis (KOA) is regarded as the foremost cause of functional limitations during daily life in elderly, such as difficulty in stair climbing. Being able to accurately monitor KOA patients’ activity during daily life could provide valuable information. Currently used activity monitors (AM) are only able to detect stepping and sedentary behaviour. Therefore, the aim of this study was to analyse whether a newly developed activity monitor can accurately classify additional activities and to compare its accuracy versus two established devices.

Time-dependent changes in postural control in early Parkinson’s disease: what are we missing?

Del Din S, Godfrey A, Coleman S, Galna B, Lord S, Rochester L.

Medical & biological engineering & computing (2016)

Abstract: Impaired postural control (PC) is an important feature of Parkinson’s disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, ... Impaired postural control (PC) is an important feature of Parkinson’s disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, and identified outcomes most sensitive to pathology. Thirty-one controls and 26 PD patients were recruited: PC was measured with an accelerometer on the lower back for 2 minutes (mins). Preliminary analysis (autocorrelation) that showed 2 seconds (s) was the shortest duration sensitive to changes in the signal; time series analysis of a range of PC outcomes was undertaken using consecutive 2-s windows over the test. Piecewise linear regression was used to fit the time series data during the first 30 s and the subsequent 90 s of the trial. PC outcomes changed over the 2 mins, with the greatest change observed during the first 30 s after which PC stabilised. Changes in PC were reduced in PD compared to controls, and Jerk was found to be discriminative of pathology. Previous studies focusing on average performance over the duration of a test may miss time-dependent differences. Evaluation of time-dependent change may provide useful insights into PC in PD and effectiveness of intervention.

A multi-resolution investigation for postural transition detection and quantification using a single wearable

Hickey A, Galna B, Mathers JC, Rochester L, Godfrey A.

Gait & posture (2016)

Abstract: Background: Multi-resolution analyses involving wavelets are commonly applied to data derived from accelerometer-based wearable technologies (wearables) to identify and quantify postural transitions (PTs). Previous studies fail to provide rationale to inform their choice of wavelet and scale approxi... Background: Multi-resolution analyses involving wavelets are commonly applied to data derived from accelerometer-based wearable technologies (wearables) to identify and quantify postural transitions (PTs). Previous studies fail to provide rationale to inform their choice of wavelet and scale approximation when utilising discrete wavelet transforms. This study examines varying combinations of those parameters to identify best practice recommendations for detecting and quantifying sit-to-stand (SiSt) and stand-to-sit (StSi) PTs. Methods: 39 young and 37 older participants completed three SiSt and StSi PTs on supported and unsupported chair types while wearing a single tri-axial accelerometer-based wearable on the lower back. Transition detection and duration were calculated through peak detection within the signal vector magnitude for a range of wavelets and scale approximations. A laboratory reference measure (2D video) was used for comparative analysis. Results: Detection accuracy of wavelet and scale combinations for the transitions was excellent for both SiSt (87–97%) and StSi (82–86%) PT-types. The duration of PTs derived from the wearable showed considerable bias and poor agreement compared with the reference videos. No differences were observed between chair types and age groups respectively. Conclusions: Improved detection of PTs could be achieved through the incorporation of different wavelet and scale combinations for the assessment of specific PT types in clinical and free-living settings. An upper threshold of 5th scale approximations is advocated for improved detection of multiple PT-types. However, care should be taken estimating the duration of PTs using wearables.

Movement recognition technology as a method of assessing spontaneous general movements in high risk infants.

Claire Marcroft et al.

Front. Neurol. 5:284. 2015

Abstract: Preterm birth is associated with increased risks of neurological and motor impairments such as cerebral palsy. The risks are highest in those born at the lowest gestations. Early identification of those most at risk is challenging meaning that a critical window of opportunity to improve outcomes thr... Preterm birth is associated with increased risks of neurological and motor impairments such as cerebral palsy. The risks are highest in those born at the lowest gestations. Early identification of those most at risk is challenging meaning that a critical window of opportunity to improve outcomes through therapy-based interventions may be missed. Clinically, the assessment of spontaneous general movements is an important tool, which can be used for the prediction of movement impairments in high risk infants. Movement recognition aims to capture and analyze relevant limb movements through computerized approaches focusing on continuous, objective, and quantitative assessment. Different methods of recording and analyzing infant movements have recently been explored in high risk infants. These range from camera-based solutions to body-worn miniaturized movement sensors used to record continuous time-series data that represent the dynamics of limb movements. Various machine learning methods have been developed and applied to the analysis of the recorded movement data. This analysis has focused on the detection and classification of atypical spontaneous general movements. This article aims to identify recent translational studies using movement recognition technology as a method of assessing movement in high risk infants. The application of this technology within pediatric practice represents a growing area of inter-disciplinary collaboration, which may lead to a greater understanding of the development of the nervous system in infants at high risk of motor impairment.

DOI: 10.3389/fneur.2014.00284

Instrumenting gait with an accelerometer: A system and algorithm examination

A. Godfrey, S. Del Din, G. Barrya, J.C. Mathersc, L. Rochester

Medical Engineering & Physics

Abstract: Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorith... Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required.

DOI: 10.1016/j.medengphy.2015.02.003

Laboratory based measurement of physical functioning after treatment for sarcoma using a triaxial accelerometer – A feasibility study

S. Furtado, et al

28th Annual Meeting of the European Musculo-Skeletal Oncology Society. Athens Greece

Abstract: The assessment of physical functioning is critical to understand the impact of treatment of musculoskeletal tumours. Quantitative measures may be more informative and more sensitive than traditional measures such as the Toronto Extremity Salvage Scale (TESS), but they have not been widely used in th... The assessment of physical functioning is critical to understand the impact of treatment of musculoskeletal tumours. Quantitative measures may be more informative and more sensitive than traditional measures such as the Toronto Extremity Salvage Scale (TESS), but they have not been widely used in this population (Ng Kee Kwong, Furtado et al. 2014). Aims: To pilot and test the feasibility of novel quantification of physical functioning using a triaxial accelerometer (Axivity) in a laboratory setting, Methods: Prospective cohort study (n=40) of patients treated for lower extremity sarcoma. Clinic based assessment included TESS and instrumented testing of gait, postural balance and timed up and go (iTUG) using Axivity. Results: Of 40 patients, 34 were adults (results from 6 children are being analysed). Mean age was 43 (19-89) years. They were treated for tumours in the femur (19), pelvis/hip (3), tibia (9), or ankle/foot (3). 7 had amputation. Median reported TESS values were 83.62 (8.33 - 100). Balance and Gait assessments using axivity were well tolerated and produced clinically useful data with face validity (Mancini, Salarian et al. 2012) (Senden, Grimm et al. 2009) . For eg: Postural balance (predictor of falls) measured using axivity presented with median values of F95_AP (Hz) = 1.35 (0.200 - 2.520), RMS (m/ s2) = 0.010 (0.005 - 0.088), RMS _ AP (m/ s2) = 0.007 (0.004 - 0.044). Median values for spatio-temporal parameters of gait (walking) were duration of Instrumented Timed Up and Go Test (iTUG) (seconds [s]) = 19.48 (12.95 - 40.91), step time (s) = 0.560 (0.46 - 0.90), stride time (s) = 1.070 (0.92 - 1.88), stance time (s) = 0.690 (0.59 - 1.07), swing time (s) = 0.390 (0.32 - 0.74), step length (m) = 0.670 (0.46 - 0.89), step velocity (m/s) = 1.17 ( 0.88 - 1.54). There was significant correlation between TESS and postural balance (p=0.013, r=-0.462) and iTUG (p=0.020, r=-0.438) Conclusion: This study supports the feasibility of Axivity to quantitatively measure physical function after treatment for lower extremity musculoskeletal tumours in the clinic. Results agree in part with patient reported function. References: 1 Ng Kee Kwong, T., et al. (2014). "What do we know about survivorship after treatment for extremity sarcoma? A systematic review." Eur J Surg Oncol. 2 Mancini, M., et al. (2012). "ISway: a sensitive, valid and reliable measure of postural control." J Neuroeng Rehabil 9: 59. Senden, R., et al. (2009). "Acceleration-based gait test for healthy subjects: reliability and reference data." Gait Posture 30(2): 192-196. Funded by Children with Cancer Charity and Sarcoma UK Charities

DOI: http://emsos2015.gr/ABSTRACTS-ONLINE/abstracts/EMSOS_2015_FC_173.pdf

Time-dependent changes in postural control in early Parkinson's disease: what are we missing?

Silvia Del Din et al

Medical & Biological Engineering & Computing

Abstract: Impaired postural control (PC) is an important feature of Parkinson's disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, an... Impaired postural control (PC) is an important feature of Parkinson's disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, and identified outcomes most sensitive to pathology. Thirty-one controls and 26 PD patients were recruited: PC was measured with an accelerometer on the lower back for 2 minutes (mins). Preliminary analysis (autocorrelation) that showed 2 seconds (s) was the shortest duration sensitive to changes in the signal; time series analysis of a range of PC outcomes was undertaken using consecutive 2-s windows over the test. Piecewise linear regression was used to fit the time series data during the first 30 s and the subsequent 90 s of the trial. PC outcomes changed over the 2 mins, with the greatest change observed during the first 30 s after which PC stabilised. Changes in PC were reduced in PD compared to controls, and Jerk was found to be discriminative of pathology. Previous studies focusing on average performance over the duration of a test may miss time-dependent differences. Evaluation of time-dependent change may provide useful insights into PC in PD and effectiveness of intervention.

DOI: 10.1007/s11517-015-1324-5

Assessment of Algorithm Performance During Variation of Sensor Location and Protocol

N. Hurwitz et al

4th International Conference on Ambulatory Monitoring of Physical Activity and Movement (ICAMPAM), At University of Limerick

Abstract: Poster available at https://goo.gl/eZNLJ9... Poster available at https://goo.gl/eZNLJ9

DOI: https://www.researchgate.net/profile/Aodhan_Hickey/publication/278301475_Assessment_of_Algorithm_Performance_During_Variation_of_Sensor_Location_and_Protocol/links/557ea62608ae26eada8dd8eb.pdf?ev=pub_int_doc_dl&origin=publication_detail&inViewer=true&msrp=Tls%2FdFCBTkmTQnwVpUY2ZURrYmycO%2FWTjogP4whk9XDu78fCQwTVfcI5bVsZ%2Fy%2BmaFgK3Bfy1kk8yR1GG6P9QW8f3BptLAo8loSIKC1cTfg%3D_qQGSRJsQ0sPN7oO5zzy2zU%2BFSnJNTWHphMeWALJGy8S1IAd09PlVGlPkVyUBJtD4iQA4Z6aBkFaecOLWt0x8rQ%3D%3D

Effect of Wavelet and Scale on Accelerometer-Based Postural Transition Detection

A. Hickey et al

4th International Conference on Ambulatory Monitoring of Physical Activity and Movement (ICAMPAM), At University of Limerick, Ireland

Abstract: Poster available at https://goo.gl/E2EHJP... Poster available at https://goo.gl/E2EHJP

DOI: https://www.researchgate.net/profile/Aodhan_Hickey/publication/278301385_Effect_of_Wavelet_and_Scale_on_Accelerometer-Based_Postural_Transition_Detection/links/557ea6c908aec87640dc8267.pdf?ev=pub_int_doc_dl&origin=publication_detail&inViewer=true&msrp=fgZxxdel%2FO%2FYz%2B%2BD0VWLMsKDGGkr7IX6341zFW2QI%2F0RuBUI%2Bm0aK8vKqhnhhq%2BPmt2mN8EUnYifFcMZwTOcz%2BtW5b5G2HIqndv4j9gXimk%3D_al8MN%2BWSV8AQK1LfPMWFS0gbA0dy7VaQyB7wkhnZPz4U26aMUW5Ta9czdZQQ7vxLWa1IOQPUlrdIxtDnoe9d%2BQ%3D%3D

Body-Worn Sensors in Parkinson's Disease: Evaluating Their Acceptability to Patients.

James Michael Fisher et al

Telemedicine and E-Health. July 2015

Abstract: Remote monitoring of symptoms in Parkinson's disease (PD) using body-worn sensors would assist treatment decisions and evaluation of new treatments. To date, a rigorous, systematic evaluation of the acceptability of body-worn sensors in PD has not been undertaken. Thirty-four participants wore bilat... Remote monitoring of symptoms in Parkinson's disease (PD) using body-worn sensors would assist treatment decisions and evaluation of new treatments. To date, a rigorous, systematic evaluation of the acceptability of body-worn sensors in PD has not been undertaken. Thirty-four participants wore bilateral wrist-worn sensors for 4 h in a research facility and then for 1 week at home. Participants' experiences of wearing the sensors were evaluated using a Likert-style questionnaire after each phase. Qualitative data were collected through free-text responses. Differences in responses between phases were assessed by using the Wilcoxon rank-sum test. Content analysis of qualitative data was undertaken. "Non-wear time" was estimated via analysis of accelerometer data for periods when sensors were stationary. After prolonged wearing there was a negative shift in participants' views on the comfort of the sensor; problems with the sensor's strap were highlighted. However, accelerometer data demonstrated high patient concordance with wearing of the sensors. There was no evidence that participants were less likely to wear the sensors in public. Most participants preferred wearing the sensors to completing symptom diaries. The finding that participants were not less likely to wear the sensors in public provides reassurance regarding the ecological validity of the data captured. The validity of our findings was strengthened by "triangulation" of data sources, enabling patients to express their agenda and repeated assessment after prolonged wearing. Long-term monitoring with wrist-worn sensors is acceptable to this cohort of PD patients. Evaluation of the wearer's experience is critical to the development of remote monitoring technology.

DOI: 10.1089/tmj.2015.0026

Accelerometer based free-living data: does macro gait behaviour differ between fallers and non-fallers with and without Parkinson's disease?

Silvia Del Din, Alan Godfrey, Brook Galna, Kim Dockx, Elisa Pelosin, Miriam Reelick, Anat Mirelman, Jeffrey M Hausdorff, Lynn Rochester

2015 ISPGR World Congress, At Seville

Abstract: Gait impairment and falls are frequent among older adults and people with Parkinson’s disease (PD), and may lead to loss of functional independence and poor quality of life. Current approaches for evaluating falls risk are based on self-report or testing at a given time point and therefore may be ... Gait impairment and falls are frequent among older adults and people with Parkinson’s disease (PD), and may lead to loss of functional independence and poor quality of life. Current approaches for evaluating falls risk are based on self-report or testing at a given time point and therefore may be suboptimal. Continuous monitoring of gait is emerging as a powerful tool to assess motor impairment and falls risk in real life using accelerometer-based technology, potentially providing an accurate and objective measure of risk [1]. Macro level gait behaviours (e.g., volume, pattern, and variability of walking bouts) are sensitive to PD pathology [2], however, there are conflicting reports about their association with falls risk. The aim of this study was to explore the association between physical activity (PA) and falls history by analysing whether macro level gait behaviour differs between fallers and non-fallers with and without PD using 7 day accelerometer- based free-living data.
METHODS: 227 fallers (F: 106 elderly, 121 PD; age: 76±6 yrs, and 72±6 yrs, respectively) enrolled in the V-TIME study [3], who fell twice or more in the 6 months prior to assessment, together with 65 participants without a history of falls (NF: 50 elderly, 15 PD, age: 65±9 yrs, 70±7 yrs, respectively) enrolled into ICICLE-GAIT [2] were tested. Data were recorded continuously for 7 days with a tri-axial accelerometer (Axivity AX3, UK, 100Hz, ±8g) placed on the low back (L5). Macro level outcomes (MLO) representing the volume (% walking time, number of steps, mean bout length), pattern (alpha (α)), and variability (S2) of free-living activity were extracted in MATLAB® (R2012a) [2]. General linear modelling examined the effect of fall history (F vs NF) and pathology (PD vs elderly) on MLO, controlling for age, sex and BMI.
RESULTS: Although the % walking time and number of steps was not related to fall history, F tended to walk in shorter bouts (p=.004) and had a less variable walking pattern (lower S2, p=.019) compared to NF. PD spent less time walking (p=.002), took fewer steps (p=.002), and accumulated proportionally more steps in shorter bouts (higher α) compared to the elderly (p=.006), regardless of falls history. There were no interactions between pathology and falls history for any of the outcomes.
CONCLUSIONS: Our results showed that there is an association between falls history and PA. Volume-based MLO, pattern and variability of the walking bouts derived from free-living accelerometer-based data are independently associated with a history of falls and PD. These results support the use of a single accelerometer-based sensor to assess falls risk in free living settings, however, future work is needed to confirm if MLO can predict falls, potentially guiding clinical decision making.
REFERENCES:
[1] Lord S et al., Mov Disord., 2013; 28(11):1534-43.
[2] Lord S et al., J Neurol., 2013; 260(12):2964-72.
[3] Mirelman A et al., BMC Neurol., 2013; 13:15.

Comparison of hip and low back worn Axivity AX3 and GT3X+ activity monitors

Brønd, J.C., Møller, N.C., Arvidsson, D.

ICAMPAM (2015)

Abstract: For accurate estimates of average PA, specific PA intensity levels, or individual PA behavior, continuous long-term monitoring is needed. However, poor wear compliance is not unusual with activity monitors worn around the waist using an elastic belt and contributes to significant loss of data. Vario... For accurate estimates of average PA, specific PA intensity levels, or individual PA behavior, continuous long-term monitoring is needed. However, poor wear compliance is not unusual with activity monitors worn around the waist using an elastic belt and contributes to significant loss of data. Various algorithms have been proposed to handle non-wear periods a posteriori, but without satisfactory results. Fixation of the activity monitor directly on the skin using medical adhesive tape could be a solution to improve compliance, but compromise wear comfort at the hip. A previous study investigating two different monitor placement within an elastic belt around the waist has shown that positioning does not influence the interpretation of the data at group level (3). Moving the monitor to the low back improves fixation and wear comfort but may affect the recordings of PA, and thus jeopardize the validity and comparability of the PA measure.

Utilization and harmonization of adult accelerometry data: review and expert consensus

Wijndaele, K., Westgate, K., Stephens, S.K., Blair, S.N., Bull, F.C., Chastin, S.F., Dunstan, D.W., Ekelund, U., Esliger, D.W., Freedson, P.S. and Granat, M.H.

Medicine and science in sports and exercise 47.10 (2015)

Abstract: Purpose: This study aimed to describe the scope of accelerometry data collected internationally in adults and to obtain a consensus from measurement experts regarding the optimal strategies to harmonize international accelerometry data. Methods: In March 2014, a comprehensive review was undertaken t... Purpose: This study aimed to describe the scope of accelerometry data collected internationally in adults and to obtain a consensus from measurement experts regarding the optimal strategies to harmonize international accelerometry data. Methods: In March 2014, a comprehensive review was undertaken to identify studies that collected accelerometry data in adults (sample size, n ≥ 400). In addition, 20 physical activity experts were invited to participate in a two-phase Delphi process to obtain consensus on the following: unique research opportunities available with such data, additional data required to address these opportunities, strategies for enabling comparisons between studies/countries, requirements for implementing/progressing such strategies, and value of a global repository of accelerometry data. Results: The review identified accelerometry data from more than 275,000 adults from 76 studies across 36 countries. Consensus was achieved after two rounds of the Delphi process; 18 experts participated in one or both rounds. The key opportunities highlighted were the ability for cross-country/cross-population comparisons and the analytic options available with the larger heterogeneity and greater statistical power. Basic sociodemographic and anthropometric data were considered a prerequisite for this. Disclosure of monitor specifications and protocols for data collection and processing were deemed essential to enable comparison and data harmonization. There was strong consensus that standardization of data collection, processing, and analytical procedures was needed. To implement these strategies, communication and consensus among researchers, development of an online infrastructure, and methodological comparison work were required. There was consensus that a global accelerometry data repository would be beneficial and worthwhile. Conclusions: This foundational resource can lead to implementation of key priority areas and identification of future directions in physical activity epidemiology, population monitoring, and burden of disease estimates.

Recognizing Physical Activities using Wearable Devices

Khan, A.M. and Lawo, M.

Handbook of Research on Innovations in the Diagnosis and Treatment of Dementia. IGI Global (2015)

Abstract: Physical activity is a major part of the user's context for wearable computing applications. The System should be able to acquire the user's physical activities using body worn sensors. The authors propose developing a personal activity recognition system that is practical, reliable, and can be used... Physical activity is a major part of the user's context for wearable computing applications. The System should be able to acquire the user's physical activities using body worn sensors. The authors propose developing a personal activity recognition system that is practical, reliable, and can be used for health-care related applications. They propose to use the wearable device which is a readymade, light weight, small and easy to use device for identifying physical activities (i.e. lying, sitting, walking, standing, cycling, running, ascending stairs and descending stairs), fitness studio activities (i.e. using elliptical trainer, butterfly, bench-press and pull down) and swimming techniques (i.e., dolphin, back-stroke, breast-stroke and free-style) using machine learning algorithms. In this chapter, the authors present an approach to build a system that exhibits this property and provides evidence based on user studies. Their results indicate that the system has a good accuracy rate.

Preliminary comparative study of two accelerometers performances for evaluation of dorsoventral movement in trotting horse

Brouillet, N., Jarlot, B., Pillard, P., Bertucci, W. and Viguier, E.

Computer Methods in Biomechanics and Biomedical Engineering 18.sup1 (2015)

Abstract: Quantification of motion by accelerometry in horses is a recent analysis technique. minimally invasive, and with many possibilities of use, whether in monitoring preparing these athletes, in the support to veterinary diagnostic or monitoring the follow up of pathology and his treatment (Bailly 2009... Quantification of motion by accelerometry in horses is a recent analysis technique. minimally invasive, and with many possibilities of use, whether in monitoring preparing these athletes, in the support to veterinary diagnostic or monitoring the follow up of pathology and his treatment (Bailly 2009). This technique allows to qualify and quantify the movement, including giving specific values to the frequency of strides, the dorsoventral elevation, propulsion or rebound of studied paces. The aim of the study was to compare the ability of two accelerometers to give reliable values of a vertical displacement (rotating movement of an ergometer pedal to choose the optimal frequency of use for the accelerometers, quantification of the dorsal-ventral trips to the trotting horses).

G-Force Exposure and Functional Recovery in High School Ice Hockey Players

Kwiecien, S.Y., Olinto, L., Kim, A.H., Nicholas, S.J. and McHugh, M.P.

American College of Sports Medicine Annual Meeting (2015)

Abstract: Purpose: To measure G-force exposure in games and practices of high school hockey players over the course of 1season and record weekly functional recovery. Methods: 6 players from a high school hockey team (age 15±1.2 yr, height 1.8±0.1 m, mass 68±12.0 kg) wereinstrumented with accelerometers dur... Purpose: To measure G-force exposure in games and practices of high school hockey players over the course of 1season and record weekly functional recovery. Methods: 6 players from a high school hockey team (age 15±1.2 yr, height 1.8±0.1 m, mass 68±12.0 kg) wereinstrumented with accelerometers during 12 games and 17 practices over 11 weeks. Players expected to have themost on-ice time were selected for the study. A small triaxial accelerometer (mass 5 g) with a flash memory chip datalogger (Axivity, Newcastle, UK) was fitted to the players' garter belts. Data were acquired at 100 Hz. Resultant G-forcewas calculated from the raw accelerometer data collected in all 3 planes (scale ±16G). G-force data were analyzedby quantifying the time spent above 1G, 2G, etc. up to >8G. Players completed weekly functional recoveryquestionnaires on weeks 2-11 (0-30 scale;; <20 = impaired recovery). ANOVA with Bonferroni corrections was used tocompare G-force exposure in games vs. practices. Results: Resultant G-force was ≤ 2G 98% of the time in games and practices. Despite longer duration for gamesversus practices (104±15 min vs. 85±24 min P<0.01), differences in G-force exposure were only apparent at highG-force thresholds (P<0.01). Weekly functional recovery score was consistent across the season (22.6±3). Impairedrecovery (<20) was evident in 8 of 60 (13%) recovery questionnaires. G-force exposure was not related to indices ofrecovery. Conclusions: Differences in G-force exposure between games and practices at high (>4G) but not low (>2G)G-force thresholds likely reflects greater physical contact in games versus practices. Functional recovery dataindicated that players mostly had adequate recovery time. This technology and method of quantifying G-forceexposure may prove useful in monitoring the physical stresses imposed on ice hockey players.

A discomfort-sensitive chair for pointing out mental fatigue

Pimenta, A., Carneiro, D., Novais, P. and Neves, J.

Ambient Intelligence-Software and Applications (2015)

Abstract: In our busy daily life, we often have the feeling of being exhausted, accompanied with a sense of performance degradation and increase of discomfort in the execution of even simple tasks. This often takes place in the workplace and in a silent way, influencing our productivity, our performance the n... In our busy daily life, we often have the feeling of being exhausted, accompanied with a sense of performance degradation and increase of discomfort in the execution of even simple tasks. This often takes place in the workplace and in a silent way, influencing our productivity, our performance the number of errors or the quality of our production. This paper details a chair to be used in workplace environments that is sensitive to the onset of fatigue. Based on built-in accelerometers it recognizes signs of discomfort, which may be related to mental fatigue, to point out moments when an individual should consider taking a pause or a rest. This chair complements a previously developed software for the assessment of mental fatigue from the analysis of the individual’s interaction with the computer.

Evaluating Input Devices for Dance Research

Haugen, M.R. and Nymoen, K.

International Symposium on Computer Music Multidisciplinary Research (2015)

Abstract: Recording music-related motions in ecologically valid situations can be challenging. We investigate the performance of three devices providing 3D acceleration data, namely Axivity AX3, iPhone 4s and a Wii controller tracking rhythmic motions. The devices are benchmarked against an infrared motion ca... Recording music-related motions in ecologically valid situations can be challenging. We investigate the performance of three devices providing 3D acceleration data, namely Axivity AX3, iPhone 4s and a Wii controller tracking rhythmic motions. The devices are benchmarked against an infrared motion capture system, tested on both simple and complex music-related body motions, and evaluations are presented of the data quality and suitability for tracking music-related motions in real-world situations. The various systems represent different trade-offs with respect to data quality, user interface and physical attributes.

Balance and coordination after viewing stereoscopic 3D television

Read, J.C., Simonotto, J., Bohr, I., Godfrey, A., Galna, B., Rochester, L. and Smulders, T.V.

Royal Society open science 2.7 (2015)

Abstract: Manufacturers and the media have raised the possibility that viewing stereoscopic 3D television (S3D TV) may cause temporary disruption to balance and visuomotor coordination. We looked for evidence of such effects in a laboratory-based study. Four hundred and thirty-three people aged 4–82 years o... Manufacturers and the media have raised the possibility that viewing stereoscopic 3D television (S3D TV) may cause temporary disruption to balance and visuomotor coordination. We looked for evidence of such effects in a laboratory-based study. Four hundred and thirty-three people aged 4–82 years old carried out tests of balance and coordination before and after viewing an 80 min movie in either conventional 2D or stereoscopic 3D, while wearing two triaxial accelerometers. Accelerometry produced little evidence of any change in body motion associated with S3D TV. We found no evidence that viewing the movie in S3D causes a detectable impairment in balance or in visuomotor coordination.

Impacto: Simulating physical impact by combining tactile stimulation with electrical muscle stimulation

Lopes, P., Ion, A. and Baudisch, P.

Proceedings of the 28th Annual ACM Symposium on User Interface Software & Technology (2015)

Abstract: We present impacto, a device designed to render the haptic sensation of hitting or being hit in virtual reality. The key idea that allows the small and light impacto device to simulate a strong hit is that it decomposes the stimulus: it renders the tactile aspect of being hit by tapping the skin usi... We present impacto, a device designed to render the haptic sensation of hitting or being hit in virtual reality. The key idea that allows the small and light impacto device to simulate a strong hit is that it decomposes the stimulus: it renders the tactile aspect of being hit by tapping the skin using a solenoid; it adds impact to the hit by thrusting the user's arm backwards using electrical muscle stimulation. The device is self-contained, wireless, and small enough for wearable use, thus leaves the user unencumbered and able to walk around freely in a virtual environment. The device is of generic shape, allowing it to also be worn on legs, so as to enhance the experience of kicking, or merged into props, such as a baseball bat. We demonstrate how to assemble multiple impacto units into a simple haptic suit. Participants of our study rated impact simulated using impacto's combination of solenoid hit and electrical muscle stimulation as more realistic than either technique in isolation.

Information and Risk Modification Trial (INFORM): design of a randomised controlled trial of communicating different types of information about coronary heart disease risk, alongside lifestyle advice, to achieve change in health-related behaviour

Silarova, B., Lucas, J., Butterworth, A.S., Di Angelantonio, E., Girling, C., Lawrence, K., Mackintosh, S., Moore, C., Payne, R.A., Sharp, S.J. and Shefer, G.

BMC public health 15.1 (2015)

Abstract: Background: Cardiovascular disease (CVD) remains the leading cause of death globally. Primary prevention of CVD requires cost-effective strategies to identify individuals at high risk in order to help target preventive interventions. An integral part of this approach is the use of CVD risk scores. L... Background: Cardiovascular disease (CVD) remains the leading cause of death globally. Primary prevention of CVD requires cost-effective strategies to identify individuals at high risk in order to help target preventive interventions. An integral part of this approach is the use of CVD risk scores. Limitations in previous studies have prevented reliable inference about the potential advantages and the potential harms of using CVD risk scores as part of preventive strategies. We aim to evaluate short-term effects of providing different types of information about coronary heart disease (CHD) risk, alongside lifestyle advice, on health-related behaviours. Methods/Design: In a parallel-group, open randomised trial, we are allocating 932 male and female blood donors with no previous history of CVD aged 40–84 years in England to either no intervention (control group) or to one of three active intervention groups: i) lifestyle advice only; ii) lifestyle advice plus information on estimated 10-year CHD risk based on phenotypic characteristics; and iii) lifestyle advice plus information on estimated 10-year CHD risk based on phenotypic and genetic characteristics. The primary outcome is change in objectively measured physical activity. Secondary outcomes include: objectively measured dietary behaviours; cardiovascular risk factors; current medication and healthcare usage; perceived risk; cognitive evaluation of provision of CHD risk scores; and psychological outcomes. The follow-up assessment takes place 12 weeks after randomisation. The experiences, attitudes and concerns of a subset of participants will be also studied using individual interviews and focus groups. Discussion: The INFORM study has been designed to provide robust findings about the short-term effects of providing different types of information on estimated 10-year CHD risk and lifestyle advice on health-related behaviours. Trial registration: Current Controlled Trials ISRCTN17721237. Registered 12 January 2015.

Recognizing social gestures with a wrist-worn smartband

Knighten, J., McMillan, S., Chambers, T. and Payton, J.

Pervasive Computing and Communication Workshops (PerCom Workshops), IEEE (2015)

Abstract: The ability to recognize social gestures opens the door for the development of enhanced pervasive computing applications that are responsive to users' social interactions. In this paper, we explore the feasibility of using a smartband for social gesture recognition. We apply logistic regression, a s... The ability to recognize social gestures opens the door for the development of enhanced pervasive computing applications that are responsive to users' social interactions. In this paper, we explore the feasibility of using a smartband for social gesture recognition. We apply logistic regression, a supervised machine learning technique, to accelerometer data collected in a study of 32 users performing 12 social gestures. Our experimental results show promise for recognizing social gestures with a smartband; our simple approach achieves an average accuracy of 86% for classification of social gestures.

iCap: Instrumented assessment of physical capability.

Godfrey, A., Lara, J., Del Din, S., Hickey, A., Munro, C.A., Wiuff, C., Chowdhury, S.A., Mathers, J.C. and Rochester, L.

Maturitas, 82 (2015)

Abstract: Objectives: The aims of this study were to (i) investigate instrumented physical capability (iCap) as a valid method during a large study and (ii) determine whether iCap can provide important additional features of postural control and gait to categorise cohorts not previously possible with manual r... Objectives: The aims of this study were to (i) investigate instrumented physical capability (iCap) as a valid method during a large study and (ii) determine whether iCap can provide important additional features of postural control and gait to categorise cohorts not previously possible with manual recordings. Study design: Cross-sectional analysis involving instrumented testing on 74 adults who were recruited as part of a pilot intervention study; LiveWell. Participants wore a single accelerometer-based monitor (lower back) during standardised physical capability tests so that outcomes could be compared directly with manual recordings (stopwatch and measurement tape) made concurrently. Main outcome measures: Time, distance, postural control and gait characteristics. Results: Agreement between manual and iCap ranged from moderate to excellent (0.649–0.983) with mean differences between methods low and deemed acceptable. Additionally, iCap successfully quantified (i) postural control characteristics which showed sensitivity to distinguish between 5 variations of the standing balance test and (ii) 14 gait characteristics known to be sensitive to age/pathology. Conclusions: Our findings show that iCap can provide robust quantitative data about physical capability during standardised tests while also providing sensitive (age/pathology) postural control and gait characteristics not previously quantifiable with manual recordings. The methodology which we propose may have practical utility in a wide range of clinical and public health surveys and studies, including intervention studies, where assessment could be undertaken within diverse settings. This will need to be tested in further validation studies in a wider range of settings.

Assessing arthroscopic skills using wireless elbow-worn motion sensors

Kirby, G.S., Guyver, P., Strickland, L., Alvand, A., Yang, G.Z., Hargrove, C., Lo, B.P. and Rees, J.L.

J Bone Joint Surg Am 97.13 (2015)

Abstract: Background: Assessment of surgical skill is a critical component of surgical training. Approaches to assessment remain predominantly subjective, although more objective measures such as Global Rating Scales are in use. This study aimed to validate the use of elbow-worn, wireless, miniaturized motion... Background: Assessment of surgical skill is a critical component of surgical training. Approaches to assessment remain predominantly subjective, although more objective measures such as Global Rating Scales are in use. This study aimed to validate the use of elbow-worn, wireless, miniaturized motion sensors to assess the technical skill of trainees performing arthroscopic procedures in a simulated environment. Methods: Thirty participants were divided into three groups on the basis of their surgical experience: novices (n = 15), intermediates (n = 10), and experts (n = 5). All participants performed three standardized tasks on an arthroscopic virtual reality simulator while wearing wireless wrist and elbow motion sensors. Video output was recorded and a validated Global Rating Scale was used to assess performance; dexterity metrics were recorded from the simulator. Finally, live motion data were recorded via Bluetooth from the wireless wrist and elbow motion sensors and custom algorithms produced an arthroscopic performance score. Results: Construct validity was demonstrated for all tasks, with Global Rating Scale scores and virtual reality output metrics showing significant differences between novices, intermediates, and experts (p < 0.001). The correlation of the virtual reality path length to the number of hand movements calculated from the wireless sensors was very high (p < 0.001). A comparison of the arthroscopic performance score levels with virtual reality output metrics also showed highly significant differences (p < 0.01). Comparisons of the arthroscopic performance score levels with the Global Rating Scale scores showed strong and highly significant correlations (p < 0.001) for both sensor locations, but those of the elbow-worn sensors were stronger and more significant (p < 0.001) than those of the wrist-worn sensors. Conclusions: A new wireless assessment of surgical performance system for objective assessment of surgical skills has proven valid for assessing arthroscopic skills. The elbow-worn sensors were shown to achieve an accurate assessment of surgical dexterity and performance. Clinical Relevance: The validation of an entirely objective assessment of arthroscopic skill with wireless elbow-worn motion sensors introduces, for the first time, a feasible assessment system for the live operating theater with the added potential to be applied to other surgical and interventional specialties.

Activity Recognition for Dogs Based on Time-series Data Analysis

Kiyohara, T., Orihara, R., Sei, Y., Tahara, Y. and Ohsuga, A.

International Conference on Agents and Artificial Intelligence (2015)

Abstract: Dogs are one of the most popular pets in the world, and more than 10 million dogs are bred annually in Japan now [4]. Recently, primitive commercial services have been started that record dogs’ activities and report them to their owners. Although it is expected that an owner would like to know the... Dogs are one of the most popular pets in the world, and more than 10 million dogs are bred annually in Japan now [4]. Recently, primitive commercial services have been started that record dogs’ activities and report them to their owners. Although it is expected that an owner would like to know the dog’s activity in greater detail, a method proposed in a previous study has failed to recognize some of the key actions. The demand for their identification is highlighted in responses to our questionnaire. In this paper, we show a method to recognize the actions of the dog by attaching only one off-the-shelf acceleration sensor to the neck of the dog. We apply DTW-D which is the state-of-the-art time series data search technique for activity recognition. Application of DTW-D to activity recognition of an animal is unprecedented according to our knowledge, and thus is the main contribution of this study. As a result, we were able to recognize eleven different activities with 75.1 % classification F-measure. We also evaluate the method taking account of real-world use cases.

Towards a canine-human communication system based on head gestures

Valentin, G., Alcaidinho, J., Howard, A., Jackson, M.M. and Starner, T.

Proceedings of the 12th International Conference on Advances in Computer Entertainment Technology. ACM (2015)

Abstract: We explored symbolic canine-human communication for working dogs through the use of canine head gestures. We identified a set of seven criteria for selecting head gestures and identified the first four deserving further experimentation. We devised computationally inexpensive mechanisms to prototype ... We explored symbolic canine-human communication for working dogs through the use of canine head gestures. We identified a set of seven criteria for selecting head gestures and identified the first four deserving further experimentation. We devised computationally inexpensive mechanisms to prototype the live system from a motion sensor on the dog's collar. Each detected gesture is paired with a predetermined message that is voiced to the humans by a smart phone. We examined the system and proposed gestures in two experiments, one indoors and one outdoors. Experiment A examined both gesture detection accuracy and a dog's ability to perform the gestures using a predetermined routine of cues. Experiment B examined the accuracy of this system on two outdoor working-dog scenarios. The detection mechanism we presented is sufficient to point to improvements into system design and provide valuable insights into which gestures fulfill the seven minimum criteria.

Dancing with horses: automated quality feedback for dressage riders

Thompson, R., Kyriazakis, I., Holden, A., Olivier, P. and Plötz, T.

Proceedings of the 2015 ACM International Joint Conference on Pervasive and Ubiquitous Computing. ACM (2015)

Abstract: The sport of dressage has become very popular not only amongst professional athletes but increasingly also for private horse owners. In well-defined tests, rider and horse execute movements, which demonstrate the strength, endurance, and dexterity of the animal as well as the quality of the interact... The sport of dressage has become very popular not only amongst professional athletes but increasingly also for private horse owners. In well-defined tests, rider and horse execute movements, which demonstrate the strength, endurance, and dexterity of the animal as well as the quality of the interaction between rider and horse. Whilst at a professional level intensive expert coaching to refine the skill set of horse and rider is standard, such an approach to progression is not usually viable for the large amateur population. In this paper we present a framework for automated generation of quality feedback in dressage tests. Using on-body sensing and automated measurement of key performance attributes we are able to monitor the quality of horse movements in an objective way. We validated the developed framework in a large-scale deployment study and report on the practical usefulness of automatically generated quality feedback in amateur dressage.

Proprioceptive interaction

Lopes, P., Ion, A., Mueller, W., Hoffmann, D., Jonell, P. and Baudisch, P.

Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems. ACM (2015)

Abstract: We propose a new way of eyes-free interaction for wearables. It is based on the user's proprioceptive sense, i.e., rather than seeing, hearing, or feeling an outside stimulus, users feel the pose of their own body. We have implemented a wearable device called Pose-IO that offers input and output bas... We propose a new way of eyes-free interaction for wearables. It is based on the user's proprioceptive sense, i.e., rather than seeing, hearing, or feeling an outside stimulus, users feel the pose of their own body. We have implemented a wearable device called Pose-IO that offers input and output based on proprioception. Users communicate with Pose-IO through the pose of their wrists. Users enter information by performing an input gesture by flexing their wrist, which the device senses using a 3-axis accelerometer. Users receive output from Pose-IO by find-ing their wrist posed in an output gesture, which Pose-IO actuates using electrical muscle stimulation. This mechanism allows users to interact with Pose-IO without visual or auditory senses, but through the proprioceptive sense alone. We developed three simple applications that demonstrate symmetric proprioceptive interaction, where input and output occur through the same limb, as well as asymmetric interaction, where input and output occur through different limbs. In a first user study, participants using a symmetric proprioceptive interface re-entered poses received from Pose-IO with an average accuracy of 5.8° despite the minimal bandwidth offered by the device. In a second, exploratory study, we investigated participants' emotional response to asymmetric proprioceptive interaction and the concept of the user's body serving as interface. Participants reported to enjoy the experience (4.6 out of 5).

Exploring gesture sonification to support reflective craft practice

Smith, T., Bowen, S.J., Nissen, B., Hook, J., Verhoeven, A., Bowers, J., Wright, P. and Olivier, P.

Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems. ACM (2015)

Abstract: Much of the knowing employed in skilled craft practice is difficult to communicate solely through written or verbal description. Consequently, the reflection and development of a craft practice in this manner may miss important nuances of practitioners' skills and experiences. We created digital tec... Much of the knowing employed in skilled craft practice is difficult to communicate solely through written or verbal description. Consequently, the reflection and development of a craft practice in this manner may miss important nuances of practitioners' skills and experiences. We created digital technologies to sonify (using audio to perceptualize data) a group of craft practitioners' gestures to explore how we can aid their reflection in and on their craft, and consequently develop it. Over a number of workshops, the design of these sonifications were iterated based on how the practitioners responded to them. We found that direct sonification of gesture (sounds generated directly from motion sensor data) helped practitioners understand and reflect upon their own and each other's practice, encouraged discussion and enabled modification of craft technique.

The Horsens-Aarhus Femoro Acetabular Impingement (HAFAI) cohort: outcome of arthroscopic treatment for femoroacetabular impingement. Protocol for a prospective cohort study.

Kierkegaard, S., Lund, B., Dalgas, U., Sørensen, H., Søballe, K. and Mechlenburg, I.

BMJ open 5.9 (2015)

Abstract: Introduction: During the past decade, it has become increasingly more common to offer hip arthroscopic surgery when treating people with femoroacetabular impingement (FAI). Nevertheless, the latest reviews conclude that it still remains to be properly investigated how surgery affects the patients. S... Introduction: During the past decade, it has become increasingly more common to offer hip arthroscopic surgery when treating people with femoroacetabular impingement (FAI). Nevertheless, the latest reviews conclude that it still remains to be properly investigated how surgery affects the patients. Specifically, detailed information on the functional, muscular and mechanical impact of surgery in larger groups is lacking. Furthermore, the long-term outcome of the surgery is still to be investigated. Methods and analysis: In this prospective cohort study, a total of 60 patients with FAI scheduled for arthroscopic surgery will be followed and tested preoperatively, and again after 3, 6, 9 and 12 months. Assessment includes isokinetic dynamometry evaluating hip flexion and extension; evaluation of functional capacity in a three-dimensional motion laboratory; pain assessment; self-reported function, quality of life, expectation and satisfaction with the surgery; recording of previous and present sporting activities and accelerometry. In addition, data on surgical procedure, rehabilitation progress, adverse events and failure will be recorded. Patients will be compared with an age-matched and gender-matched reference group of 30 persons with no hip, knee, ankle or back problems. Long-term follow-up of this cohort may evaluate possible reoperations and development of hip osteoarthritis. Furthermore, analysis on how subgroups respond to the treatment could be performed together with identification of possible “non-responders”. Ethics and dissemination: The study is approved by the Central Denmark Region Committee on Biomedical Research Ethics (Journal No 1-10-72-239-14). The results from this study will be presented at national and international congresses and published in peer-reviewed journals.

Instrumented assessment of test battery for physical capability using an accelerometer: a feasibility study

Godfrey, A., Lara, J., Munro, C.A., Wiuff, C., Chowdhury, S.A., Del Din, S., Hickey, A., Mathers, J.C. and Rochester, L.

Physiological measurement 36.5 (2015)

Abstract: Recent work has identified subdomains (tests) of physical capability that are recommended for assessment of the healthy ageing phenotype (HAP). These include: postural control, locomotion, endurance, repeated sit-to-stand-to-sit and TUG. Current assessment methods lack sensitivity and are error pron... Recent work has identified subdomains (tests) of physical capability that are recommended for assessment of the healthy ageing phenotype (HAP). These include: postural control, locomotion, endurance, repeated sit-to-stand-to-sit and TUG. Current assessment methods lack sensitivity and are error prone due to their lack of consistency and heterogeneity of reported outcomes; instrumentation with body worn monitors provides a method to address these potential weaknesses. This work proposes the use of a single tri-axial accelerometer-based device with appropriate algorithms (referred to here as a body worn monitor, BWM) for the purposes of instrumented testing during physicality capability assessment. In this pilot study we present 14 BWM-based outcomes across the subdomains which include magnitude, frequency and spatio-temporal characteristics. Where possible, we compared BWM outcomes with manually recorded values and found no significant differences between locomotion and TUG tasks (p = 0.319). Significant differences were found for the total distance walked during endurance (p = 0.037) and times for repeated sit-to-stand-to-sit transitions (p < 0.000). We identified reasons for differences and make recommendations for future testing. We were also able to quantify additional characteristics of postural control and gait which could be sensitive outcomes for future HAP assessment. Our findings demonstrate the feasibility of this method to enhance measurement of physical capacity. The methodology can also be applied to a wide variety of accelerometer-based monitors and is applicable to a range of intervention-based studies or pathological assessment.

Instrumenting gait with an accelerometer: a system and algorithm examination

Godfrey, A., Del Din, S., Barry, G., Mathers, J.C. and Rochester, L.

Medical engineering & physics 37.4 (2015)

Abstract: Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorith... Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required.

Activity recognition in naturalistic environments using body-worn sensors

Hammerla, N.Y.

Phd Thesis (2015)

Abstract: The research presented in this thesis investigates how deep learning and feature learning can address challenges that arise for activity recognition systems in naturalistic, ecologically valid surroundings such as the private home. One of the main aims of ubiquitous computing is the development of a... The research presented in this thesis investigates how deep learning and feature learning can address challenges that arise for activity recognition systems in naturalistic, ecologically valid surroundings such as the private home. One of the main aims of ubiquitous computing is the development of automated recognition systems for human activities and behaviour that are sufficiently robust to be deployed in realistic, in-the-wild environments. In most cases, the targeted application scenarios are people’s daily lives, where systems have to abide by practical usability and privacy constraints. We discuss how these constraints impact data collection and analysis and demonstrate how common approaches to the analysis of movement data effectively limit the practical use of activity recognition systems in every-day surroundings. In light of these issues we develop a novel approach to the representation and modelling of movement data based on a data-driven methodology that has applications in activity recognition, behaviour imaging, and skill assessment in ubiquitous computing. A number of case studies illustrate the suitability of the proposed methods and outline how study design can be adapted to maximise the benefit of these techniques, which show promising performance for clinical applications in particular.

Impacto: Simulating physical impact by combining tactile stimulation with electrical muscle stimulation

Lopes, P., Ion, A. and Baudisch, P.

Proceedings of the 28th Annual ACM Symposium on User Interface Software & Technology. ACM (2015)

Abstract: We present impacto, a device designed to render the haptic sensation of hitting or being hit in virtual reality. The key idea that allows the small and light impacto device to simulate a strong hit is that it decomposes the stimulus: it renders the tactile aspect of being hit by tapping the skin usi... We present impacto, a device designed to render the haptic sensation of hitting or being hit in virtual reality. The key idea that allows the small and light impacto device to simulate a strong hit is that it decomposes the stimulus: it renders the tactile aspect of being hit by tapping the skin using a solenoid; it adds impact to the hit by thrusting the user's arm backwards using electrical muscle stimulation. The device is self-contained, wireless, and small enough for wearable use, thus leaves the user unencumbered and able to walk around freely in a virtual environment. The device is of generic shape, allowing it to also be worn on legs, so as to enhance the experience of kicking, or merged into props, such as a baseball bat. We demonstrate how to assemble multiple impacto units into a simple haptic suit. Participants of our study rated impact simulated using impacto's combination of solenoid hit and electrical muscle stimulation as more realistic than either technique in isolation.

Comparison of hip and low back worn Axivity AX3 and GT3X+ activity monitors

Brønd, J.C., Møller, N.C., Arvidsson, D.

ICAMPAM (2015)

Abstract: For accurate estimates of average PA, specific PA intensity levels, or individual PA behavior, continuous long-term monitoring is needed. However, poor wear compliance is not unusual with activity monitors worn around the waist using an elastic belt and contributes to significant loss of data. Vario... For accurate estimates of average PA, specific PA intensity levels, or individual PA behavior, continuous long-term monitoring is needed. However, poor wear compliance is not unusual with activity monitors worn around the waist using an elastic belt and contributes to significant loss of data. Various algorithms have been proposed to handle non-wear periods a posteriori, but without satisfactory results. Fixation of the activity monitor directly on the skin using medical adhesive tape could be a solution to improve compliance, but compromise wear comfort at the hip. A previous study investigating two different monitor placement within an elastic belt around the waist has shown that positioning does not influence the interpretation of the data at group level (3). Moving the monitor to the low back improves fixation and wear comfort but may affect the recordings of PA, and thus jeopardize the validity and comparability of the PA measure.

The relationship between real world ambulatory activity and falls in incident Parkinson's disease: Influence of classification scheme

Mactier, Karen et al.

Parkinsonism & related disorders (2014).

Abstract: Abstract Introduction Few studies have categorized falls in early Parkinson's disease (PD) and little is known about falls incidence and evolution. Fall incidence and frequency are reported to be ‘U’ shaped with respect to disease severity and may be influenced by time spent engaged in ambulator... Abstract Introduction Few studies have categorized falls in early Parkinson's disease (PD) and little is known about falls incidence and evolution. Fall incidence and frequency are reported to be ‘U’ shaped with respect to disease severity and may be influenced by time spent engaged in ambulatory activity. Methods Twelve months prospective falls in an incident PD cohort (n = 111) were reported and the relationship between falls and ambulatory activity was examined in a subgroup (n = 83). Fall events were collected using standardised protocols and were categorized by fall frequency (non-faller, single fall, recurrent falls) and also by a novel classification based on pre-fall event: (1) engaged in advanced activity; (2) ambulation; and (3) transition. Non-parametric statistics compared groups in both classifications. Results At baseline 23 (20.7%) of the cohort had fallen, increasing to 41 (36.9%) participants over 12 months. Total time spent walking was significantly lower for transition fallers compared with non-fallers and ambulation fallers (p = 0.041), who also had significantly increased disease severity. There were no significant relationships when fallers were categorized by frequency. We present an inverted U curve model depicting the relationship between falls and activity over time in PD, and propose that at this stage transition and ambulation fallers occupy different places on the curve. Conclusions Falls are more common than recognised in newly-diagnosed PD. Daily activity is reduced even in early disease for people who fall during transitions. Classification methods that take pre-fall event into account may be useful to understand the heterogeneity of this complex problem.

DOI: 10.1016

Within trial validation and reliability of a single tri-axial accelerometer for gait assessment.

Alan Godfrey, Silvia Del Din, Gillian Barry, John C Mathers, Lynn Rochester

Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE. IEEE, 2014.

Abstract: Gait is a sensitive biomarker of decline in both cognitive and physical function. Therefore, the collection of gait data is an important feature of clinical assessments. Accelerometer-based body worn sensors are quickly becoming the preferred tool for assessing gait because they are small, useable i... Gait is a sensitive biomarker of decline in both cognitive and physical function. Therefore, the collection of gait data is an important feature of clinical assessments. Accelerometer-based body worn sensors are quickly becoming the preferred tool for assessing gait because they are small, useable in a wide variety of settings, offer more continuous spatio-temporal analysis and are inexpensive when compared with traditional gait assessment methodologies. The purpose of this study was to determine the validity and within test reliability of a low cost body worn movement sensor with associated algorithms to assess gait in a large group of older and younger healthy adults. We collected gait data over intermittent walks on an instrumented walkway for a within trial validation and also used the same accelerometer derived gait data for a within test reliability analysis. ICCs for validation and reliability were >0.756 and >0.965, respectively.

DOI: 10.1109/EMBC.2014.6944969

A comparison of methods to detect postural transitions using a single tri-axial accelerometer.

Alan Godfrey, Gillian Barry, John C Mathers, Lynn Rochester

Engineering in Medicine and Biology Society (EMBC), 2014 36th Annual International Conference of the IEEE. IEEE, 2014.

Abstract: Two algorithms for evaluating postural transitions (PTs) in cohorts of 40 healthy younger and 40 older adults are described and evaluated. The time of sit-to-stand (SiSt) and stand-to-sit (StSi) transitions and their duration were measured with two tri-axial accelerometers, one on the chest and one ... Two algorithms for evaluating postural transitions (PTs) in cohorts of 40 healthy younger and 40 older adults are described and evaluated. The time of sit-to-stand (SiSt) and stand-to-sit (StSi) transitions and their duration were measured with two tri-axial accelerometers, one on the chest and one on the lower back. Each algorithm was optimized for these sensor placements. The first algorithm for sensor placement on the chest used a scalar product and vertical velocity estimates. The second algorithm for sensor placement on the lower back used a vector magnitude and a discrete wavelet transform. Both algorithms performed excellently in PT classification for younger and older adults (>86%). However, the chest based sensor and algorithm were better for estimating transition duration (TD) with ICCs to video analysis ranging from 0.678 to 0.969.

DOI: 10.1109/EMBC.2014.6945053

Wearable Recognition System for Sports Activities

Ali Mehmood Khan, Michael Lawo

eTELEMED 2014, The Sixth International Conference on eHealth, Telemedicine, and Social Medicine

Abstract: Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a sports activities recognition system that is practical, reliable, and can be used for health... Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a sports activities recognition system that is practical, reliable, and can be used for health-care related applications. We propose to use the axivity device which is a readymade, light weight, small and easy to use device for identifying basic physical training activities (i.e., using elliptical trainer, butterfly, bench-press and pull down ) and different swimming styles (i.e., dolphin, back-stroke, breast-stroke and free-style) using decision tree classifier, Averaged one-dependence estimators (AODE) and Neural networks. In this paper, we present an approach to build a system that exhibits this property and provides evidence based on data for 8 different activities collected from 20 different subjects. Our results indicate that the system has a good rate of accuracy.

DOI: ISBN 978-1-61208-327-8

Detecting Gunshots Using Wearable Accelerometers

Charles E. Loeffler

PloS one 9.9 (2014): e106664.

Abstract: Gun violence continues to be a staggering and seemingly intractable issue in many communities. The prevalence of gun violence among the sub-population of individuals under court-ordered community supervision provides an opportunity for intervention using remote monitoring technology. Existing monito... Gun violence continues to be a staggering and seemingly intractable issue in many communities. The prevalence of gun violence among the sub-population of individuals under court-ordered community supervision provides an opportunity for intervention using remote monitoring technology. Existing monitoring systems rely heavily on location-based monitoring methods, which have incomplete geographic coverage and do not provide information on illegal firearm use. This paper presents the first results demonstrating the feasibility of using wearable inertial sensors to recognize wrist movements and other signals corresponding to firearm usage. Data were collected from accelerometers worn on the wrists of subjects shooting a number of different firearms, conducting routine daily activities, and participating in activities and tasks that could be potentially confused with firearm discharges. A training sample was used to construct a combined detector and classifier for individual gunshots, which achieved a classification accuracy of 99.4 percent when tested against a hold-out sample of observations. These results suggest the feasibility of using inexpensive wearable sensors to detect firearm discharges.

DOI: 10.1371/journal.pone.0106664

The INTERVAL trial to determine whether intervals between blood donations can be safely and acceptably decreased to optimise blood supply: study protocol for a randomised controlled trial

Carmel Moore, Jennifer Sambrook, Matthew Walker, Zoe Tolkien, Stephen Kaptoge, David Allen, Susan Mehenny, Jonathan Mant, Emanuele Di Angelantonio, Simon G Thompson, Willem Ouwehand, David J Roberts and John Danesh

Trials 15.1 (2014): 363.

Abstract: Abstract Background: Ageing populations may demand more blood transfusions, but the blood supply could be limited by difficulties in attracting and retaining a decreasing pool of younger donors. One approach to increase blood supply is to collect blood more frequently from existing donors. If more d... Abstract Background: Ageing populations may demand more blood transfusions, but the blood supply could be limited by difficulties in attracting and retaining a decreasing pool of younger donors. One approach to increase blood supply is to collect blood more frequently from existing donors. If more donations could be safely collected in this manner at marginal cost, then it would be of considerable benefit to blood services. National Health Service (NHS) Blood and Transplant in England currently allows men to donate up to every 12 weeks and women to donate up to every 16 weeks. In contrast, some other European countries allow donations as frequently as every 8 weeks for men and every 10 weeks for women. The primary aim of the INTERVAL trial is to determine whether donation intervals can be safely and acceptably decreased to optimise blood supply whilst maintaining the health of donors. Methods/Design: INTERVAL is a randomised trial of whole blood donors enrolled from all 25 static centres of NHS Blood and Transplant. Recruitment of about 50,000 male and female donors started in June 2012 and was completed in June 2014. Men have been randomly assigned to standard 12-week versus 10-week versus 8-week inter-donation intervals, while women have been assigned to standard 16-week versus 14-week versus 12-week inter-donation intervals. Sex-specific comparisons will be made by intention-to-treat analysis of outcomes assessed after two years of intervention. The primary outcome is the number of blood donations made. A key secondary outcome is donor quality of life, assessed using the Short Form Health Survey. Additional secondary endpoints include the number of ‘deferrals’ due to low haemoglobin (and other factors), iron status, cognitive function, physical activity, and donor attitudes. A comprehensive health economic analysis will be undertaken. Discussion: The INTERVAL trial should yield novel information about the effect of inter-donation intervals on blood supply, acceptability, and donors’ physical and mental well-being. The study will generate scientific evidence to help formulate blood collection policies in England and elsewhere.

DOI: 10.1186/1745-6215-15-363

A comparison of methods to detect postural transitions using a single tri-axial accelerometer

Godfrey A, Barry G, Mathers JC, Rochester L.

Conf Proc IEEE Eng Med Biol Soc. Aug,2014:6234-7

Abstract: Two algorithms for evaluating postural transitions (PTs) in cohorts of 40 healthy younger and 40 older adults are described and evaluated. The time of sit-to-stand (SiSt) and stand-to-sit (StSi) transitions and their duration were measured with two tri-axial accelerometers, one on the chest and one ... Two algorithms for evaluating postural transitions (PTs) in cohorts of 40 healthy younger and 40 older adults are described and evaluated. The time of sit-to-stand (SiSt) and stand-to-sit (StSi) transitions and their duration were measured with two tri-axial accelerometers, one on the chest and one on the lower back. Each algorithm was optimized for these sensor placements. The first algorithm for sensor placement on the chest used a scalar product and vertical velocity estimates. The second algorithm for sensor placement on the lower back used a vector magnitude and a discrete wavelet transform. Both algorithms performed excellently in PT classification for younger and older adults (>86%). However, the chest based sensor and algorithm were better for estimating transition duration (TD) with ICCs to video analysis ranging from 0.678 to 0.969.

DOI: 10.1109/EMBC.2014.6945053.

Writing Without Keyboard: Handwriting Recognition on the Wrist

Christoph Amma et al

CES2014

Abstract: Typing text messages on the mobile phone via the tiny soft keyboard is very cumbersome. How about simply writing messages into the air? A device develo- ped by Karlsruhe Institute of Technology could make this come true: A sensor attached to the wrist recordshand movements, a computer system capture... Typing text messages on the mobile phone via the tiny soft keyboard is very cumbersome. How about simply writing messages into the air? A device develo- ped by Karlsruhe Institute of Technology could make this come true: A sensor attached to the wrist recordshand movements, a computer system captures the relevant signals and translates them into text. The novel KIT-developed “Airwriting” system allows to write letters into air, as if using an invisible board or pad.

DOI: Exhibit: www.pkm.kit.edu/cebit2014.php

Making 3D Printed Objects Interactive Using Wireless Accelerometers

Jonathan Hook et al

CHI2014 Toronto

Abstract: We present an approach that allows designers and others to quickly and easily make 3D printed objects interactive, without the need for hardware or software expertise and with little modification to an object’s physical design. With our approach, a designer simply attaches or embeds small three-ax... We present an approach that allows designers and others to quickly and easily make 3D printed objects interactive, without the need for hardware or software expertise and with little modification to an object’s physical design. With our approach, a designer simply attaches or embeds small three-axis wireless accelerometer modules into the moving parts of a 3D printed object. A simple graphical user interface is then used to configure the system to interpret the movements of these accelerometers as if they were common physical controls such as buttons or dials. The designer can then associate events generated by these controls with a range of interactive behavior, including web browser and media player control.

DOI: 10.1145/2559206.2581137

The INTERVAL trial to determine whether intervals between blood donations can be safely and acceptably decreased to optimise blood supply: study protocol for a randomised controlled trial

Moore C, Sambrook J, Walker M, Tolkien Z, Kaptoge S, Allen D, Mehenny S, Mant J, Di Angelantonio E, Thompson SG, Ouwehand W.

BMC Trials (2014)

Abstract: Background: Ageing populations may demand more blood transfusions, but the blood supply could be limited by difficulties in attracting and retaining a decreasing pool of younger donors. One approach to increase blood supply is to collect blood more frequently from existing donors. If more donations ... Background: Ageing populations may demand more blood transfusions, but the blood supply could be limited by difficulties in attracting and retaining a decreasing pool of younger donors. One approach to increase blood supply is to collect blood more frequently from existing donors. If more donations could be safely collected in this manner at marginal cost, then it would be of considerable benefit to blood services. National Health Service (NHS) Blood and Transplant in England currently allows men to donate up to every 12 weeks and women to donate up to every 16 weeks. In contrast, some other European countries allow donations as frequently as every 8 weeks for men and every 10 weeks for women. The primary aim of the INTERVAL trial is to determine whether donation intervals can be safely and acceptably decreased to optimise blood supply whilst maintaining the health of donors. Methods/Design: INTERVAL is a randomised trial of whole blood donors enrolled from all 25 static centres of NHS Blood and Transplant. Recruitment of about 50,000 male and female donors started in June 2012 and was completed in June 2014. Men have been randomly assigned to standard 12-week versus 10-week versus 8-week inter-donation intervals, while women have been assigned to standard 16-week versus 14-week versus 12-week inter-donation intervals. Sex-specific comparisons will be made by intention-to-treat analysis of outcomes assessed after two years of intervention. The primary outcome is the number of blood donations made. A key secondary outcome is donor quality of life, assessed using the Short Form Health Survey. Additional secondary endpoints include the number of ‘deferrals’ due to low haemoglobin (and other factors), iron status, cognitive function, physical activity, and donor attitudes. A comprehensive health economic analysis will be undertaken. Discussion: The INTERVAL trial should yield novel information about the effect of inter-donation intervals on blood supply, acceptability, and donors’ physical and mental well-being. The study will generate scientific evidence to help formulate blood collection policies in England and elsewhere.

ClimbAX: Skill Assessment for Climbing Enthusiasts

Ladha, C., et al.

2013 ACM Conference on Ubiquitous Computing. ACM.

Abstract: In recent years the sport of climbing has seen consistent increase in popularity. Climbing requires a complex skill set for successful and safe exercising. While elite climbers receive intensive expert coaching to refine this skill set, this progression approach is not viable for the amateur populat... In recent years the sport of climbing has seen consistent increase in popularity. Climbing requires a complex skill set for successful and safe exercising. While elite climbers receive intensive expert coaching to refine this skill set, this progression approach is not viable for the amateur population. We have developed ClimbAX, a climbing performance analysis system that aims for replicating expert assessments and thus represents a first step towards an automatic coaching system for climbing enthusiasts. Through an accelerometer based wearable sensing platform, climber’s movements are captured. An automatic analysis procedure detects climbing sessions and moves, which form the basis for subsequent performance assessment. The assessment parameters are derived from sports science literature and include: power, control, stability, speed. ClimbAX was evaluated in a large case study with 53 climbers under competition settings. We report a strong correlation between predicted scores and official competition results, which demonstrate the effectiveness of our automatic skill assessment system.

DOI: 10.1145/2493432.2493492

On Preserving Statistical Characteristics of Accelerometry Data using their Empirical Cumulative Distribution

Hammerla, N., et al.

2013 ACM Conference on Ubiquitous Computing. ACM.

Abstract: The majority of activity recognition systems in wearable computing rely on a set of statistical measures, such as means and moments, extracted from short frames of continuous sensor measurements to perform recognition. These features implicitly quantify the distribution of data observed in each fram... The majority of activity recognition systems in wearable computing rely on a set of statistical measures, such as means and moments, extracted from short frames of continuous sensor measurements to perform recognition. These features implicitly quantify the distribution of data observed in each frame. However, feature selection remains challenging and labour intensive, rendering a more generic method to quantify distributions in accelerometer data much desired. In this paper we present the ECDF representation, a novel approach to preserve characteristics of arbitrary distributions for feature extraction, which is particularly suitable for embedded applications. In extensive experiments on six publicly available datasets we demonstrate that it outperforms common approaches to feature extraction across a wide variety of tasks.

DOI: 10.1145/2493988.2494353

Dog's Life: Wearable Activity Recognition for Dogs,

Ladha, C., et al.

2013 ACM Conference on Ubiquitous Computing. ACM.

Abstract: Health and wellbeing of dogs, either domesticated pets or service animals, are major concerns that are taken seriously for ethical, emotional, and financial reasons. Welfare assessments in dogs rely on objective observations of both frequency and variability of individual behaviour traits, which is ... Health and wellbeing of dogs, either domesticated pets or service animals, are major concerns that are taken seriously for ethical, emotional, and financial reasons. Welfare assessments in dogs rely on objective observations of both frequency and variability of individual behaviour traits, which is often difficult to obtain in a dog’s everyday life. In this paper we have identified a set of activities, which are linked to behaviour traits that are relevant for a dog’s wellbeing. We developed a collar-worn accelerometry platform that records dog behaviours in naturalistic environments. A statistical classification framework is used for recognising dog activities. In an experimental evaluation we analysed the naturalistic behaviour of 18 dogs and were able to recognise a total of 17 different activities with approximately 70% classification accuracy. The presented system is the first of its kind that allows for robust and detailed analysis of dog activities in naturalistic environments.

DOI: 10.1145/2493432.2493519

Combining Embedded Accelerometers with Computer Vision for Recognizing Food Preparation Activities

Stein, S., et al.

2013 ACM Conference on Ubiquitous Computing. ACM.

Abstract: This paper introduces a publicly available dataset of complex activities that involve manipulative gestures. The dataset captures people preparing mixed salads and contains more than 4.5 hours of accelerometer and RGB-D video data, detailed annotations, and an evaluation protocol for comparison of a... This paper introduces a publicly available dataset of complex activities that involve manipulative gestures. The dataset captures people preparing mixed salads and contains more than 4.5 hours of accelerometer and RGB-D video data, detailed annotations, and an evaluation protocol for comparison of activity recognition algorithms. Providing baseline results for one possible activity recognition task, this paper further investigates modality fusion methods at different stages of the recognition pipeline: (i) prior to feature extraction through accelerometer localization, (ii) at feature level via feature concatenation, and (iii) at classification level by combining classifier outputs. Empirical evaluation shows that fusing information captured by these sensor types can considerably improve recognition performance.

DOI: 10.1145/2493432.2493482

Towards Gestural Sonic Affordances.

Altavilla, Alessandro, Baptiste Caramiaux, and Atau Tanaka.

New Interfaces for Musical Expression (NIME 2013) pp. 61-64.

Abstract: We present a study that explores the affordance evoked by sound and sound-gesture mappings. In order to do this, we make use of a sensor system with minimal form factor in a user study that minimizes cultural association. The present study focuses on understanding how participants describe sounds an... We present a study that explores the affordance evoked by sound and sound-gesture mappings. In order to do this, we make use of a sensor system with minimal form factor in a user study that minimizes cultural association. The present study focuses on understanding how participants describe sounds and gestures produced while playing designed sonic interaction mappings. This approach seeks to move from object-centric affordance towards investigating embodied gestural sonic affordances.

DOI: NIME13

Movement crafter.

Pschetz, L., Banks, R., & Molloy, M.

7th International Conference on Tangible, Embedded and Embodied Interaction (pp. 393-394). ACM.

Abstract: The movement crafter attempts to reconcile the pace of new technologies with traditional crafting activities that are performed as pastimes. The project explores concepts of quiet communication and technology hybrids and attempts to support crafting without making the craftsperson overly self-consci... The movement crafter attempts to reconcile the pace of new technologies with traditional crafting activities that are performed as pastimes. The project explores concepts of quiet communication and technology hybrids and attempts to support crafting without making the craftsperson overly self-conscious of their practice.

DOI: 10.1145/2460625.2460709

Real-Time Fall Detection and Activity Recognition Using Low-Cost Wearable Sensors

Pham, C., & Phuong, T. M.

Computational Science and Its Applications ICCSA 2013 (pp. 673-682). Springer Berlin Heidelberg.

Abstract: We present a real-time fall detection and activity recognition system (FDAR) that can be easily deployed using Wii Remotes worn on human body. Features extracted from continuous accelerometer data streams are used for training pattern recognition models, then the models are used for detecting falls ... We present a real-time fall detection and activity recognition system (FDAR) that can be easily deployed using Wii Remotes worn on human body. Features extracted from continuous accelerometer data streams are used for training pattern recognition models, then the models are used for detecting falls and recognizing 14 fine grained activities including unknown activities in realtime. An experiment on 12 subjects was conducted to rigorously evaluate the system performance. With the recognition rates as high as 91% precision and recall for 10-fold cross validation and as high as 82% precision and recall for leave one subject out evaluations, the results demonstrated that the development of real-time fall detection and activity recognition systems using low-cost sensors is feasible.

DOI: 10.1007/978-3-642-39637-3_53

Postural control during standing balance as a biomarker for healthy ageing

Godfrey A., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: Biomarkers to identify healthy ageing have become an important area of research. A recent systematic review has identified that impaired postural control during standing is associated with higher mortality rates. Accelerometry may be useful to better understand the effects of ageing on postural cont... Biomarkers to identify healthy ageing have become an important area of research. A recent systematic review has identified that impaired postural control during standing is associated with higher mortality rates. Accelerometry may be useful to better understand the effects of ageing on postural control.

DOI: ICAMPAM 2013 Conference

A comparison of commercial system to evaluate postural control during clinical testing

Del Din S., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: Postural control is an important clinical feature in people with Parkinson’s disease (PD). Traditionally postural control has been evaluated using force platforms to examine the change of centre of pressure but more recently body worn sensors incorporating accelerometers have been used to describe... Postural control is an important clinical feature in people with Parkinson’s disease (PD). Traditionally postural control has been evaluated using force platforms to examine the change of centre of pressure but more recently body worn sensors incorporating accelerometers have been used to describe parameters such as ‘Jerk’ (rate of change of acceleration) and root mean square (RMS) values. With the increasing number of accelerometer- based devices available it is important to test the agreement between sensors to ensure comparability.

DOI: ICAMPAM 2013 Conference

Variability of postural control with time in Parkinson's disease

Del Din S., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: Inertial sensors are valid instruments for characterising postural control in PD subjects who exhibit abnormalities in sway measures during quiet standing . However, most studies focus only on the absolute value of a specific sway measure during a quiet standing trial, without analysing if the measu... Inertial sensors are valid instruments for characterising postural control in PD subjects who exhibit abnormalities in sway measures during quiet standing . However, most studies focus only on the absolute value of a specific sway measure during a quiet standing trial, without analysing if the measure varies with time due to fluctuations in motor control, attention and fatigue.

DOI: ICAMPAM 2013 Conference

Measurement of sit-stand and stand-sit transitions using a tri-axial accelerometer on the lower back

Godfrey A., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: The study of ambulatory human motion with accelerometer -based activity monitors has increased in many areas of biomedical research. These research areas include the monitoring of both older and younger adults. Reduction in sensor size coupled with more powerful data mining techniques have enabled t... The study of ambulatory human motion with accelerometer -based activity monitors has increased in many areas of biomedical research. These research areas include the monitoring of both older and younger adults. Reduction in sensor size coupled with more powerful data mining techniques have enabled the use of single sensor devices for longitudinal monitoring but sensor location and algorithm complexity play a key role in deriving a more complete activity summary.

DOI: ICAMPAM 2013 Conference

Shaker Table Validation Of Openmovement Ax3 Accelerometer

Ladha, C., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: As designs of accelerometers shift towards uncompressed and unfiltered data capture, researchers are developing device insensitive algorithms. To ensure interoperability, steps need to be taken to support compensation for differences in construction. To support this step a shaker table characterizat... As designs of accelerometers shift towards uncompressed and unfiltered data capture, researchers are developing device insensitive algorithms. To ensure interoperability, steps need to be taken to support compensation for differences in construction. To support this step a shaker table characterization was made using the OpenMovement AX3 device and compared with the similar GENEA device.

DOI: ICAMPAM 2013 Conference

Accelerometry based assesment of anti-parkinsonian medication on postural control

Del Din S., et al.

3rd International Conference on Ambulatory Monitoring of Physical Activity and Movement.

Abstract: Postural control during standing is a key clinical evaluation in Parkinson's disease (PD). Subjects with PD exhibit abnormalities in sway parameters during standing. The effect of L-Dopa on postural control in people with PD has not yet been examined. Understanding this effect will provide insights ... Postural control during standing is a key clinical evaluation in Parkinson's disease (PD). Subjects with PD exhibit abnormalities in sway parameters during standing. The effect of L-Dopa on postural control in people with PD has not yet been examined. Understanding this effect will provide insights into the mechanisms underlying postural control in PD.

DOI: ICAMPAM 2013 Conference

Recognizing Physical Training Exercises Using the Axivity Device.

Khan, A. M.

Fifth International Conference on eHealth, Telemedicine, and Social Medicine (pp. 147-152).

Abstract: Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a personal activity recognition system that is practical, reliable, and can be used for health... Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a personal activity recognition system that is practical, reliable, and can be used for health-care related applications. We propose to use the axivity device [1] which is a ready-made, light weight, small and easy to use device for identifying basic physical activities like lying, sitting, walking, standing, cycling, running, ascending and descending stairs using decision tree classifier. In this paper, we present an approach to build a system that exhibits this property and provides evidence based on data for 8 different activities collected from 12 different subjects. Our results indicate that the system has an accuracy rate of approximately 92%.

DOI: ISBN 978-1-61208-252-3 p147 to 152 AM Khan

V-TIME: a treadmill training program augmented by virtual reality to decrease fall risk in older adults: study design of a randomized controlled trial

Mirelman, A., et al.

BMC Neurology, 2013 (pp. 15).

Abstract: Recent work has demonstrated that fall risk can be attributed to cognitive as well as motor deficits. Indeed, everyday walking in complex environments utilizes executive function, dual tasking, planning and scanning, all while walking forward. Pilot studies suggest that a multi-modal intervention th... Recent work has demonstrated that fall risk can be attributed to cognitive as well as motor deficits. Indeed, everyday walking in complex environments utilizes executive function, dual tasking, planning and scanning, all while walking forward. Pilot studies suggest that a multi-modal intervention that combines treadmill training to target motor function and a virtual reality obstacle course to address the cognitive components of fall risk may be used to successfully address the motor-cognitive interactions that are fundamental for fall risk reduction. The proposed randomized controlled trial will evaluate the effects of treadmill training augmented with virtual reality on fall risk. Methods/Design Three hundred older adults with a history of falls will be recruited to participate in this study. This will include older adults (n=100), patients with mild cognitive impairment (n=100), and patients with Parkinson’s disease (n=100). These three sub-groups will be recruited in order to evaluate the effects of the intervention in people with a range of motor and cognitive deficits. Subjects will be randomly assigned to the intervention group (treadmill training with virtual reality) or to the active-control group (treadmill training without virtual reality). Each person will participate in a training program set in an outpatient setting 3 times per week for 6 weeks. Assessments will take place before, after, and 1 month and 6 months after the completion of the training. A falls calendar will be kept by each participant for 6 months after completing the training to assess fall incidence (i.e., the number of falls, multiple falls and falls rate). In addition, we will measure gait under usual and dual task conditions, balance, community mobility, health related quality of life, user satisfaction and cognitive function. Discussion This randomized controlled trial will demonstrate the extent to which an intervention that combines treadmill training augmented by virtual reality reduces fall risk, improves mobility and enhances cognitive function in a diverse group of older adults. In addition, the comparison to an active control group that undergoes treadmill training without virtual reality will provide evidence as to the added value of addressing motor cognitive interactions as an integrated unit. Trial Registration (NIH)–NCT01732653

DOI: 10.1186/1471-2377-13-15

Movement crafter

Pschetz, Larissa, Richard Banks, and Mike Molloy.

7th International Conference on Tangible, Embedded and Embodied Interaction, pp. 393-394. ACM, 2013.

Abstract: The movement crafter attempts to reconcile the pace of new technologies with traditional crafting activities that are performed as pastimes. The project explores concepts of quiet communication and technology hybrids and attempts to support crafting without making the craftsperson overly self-consci... The movement crafter attempts to reconcile the pace of new technologies with traditional crafting activities that are performed as pastimes. The project explores concepts of quiet communication and technology hybrids and attempts to support crafting without making the craftsperson overly self-conscious of their practice.

DOI: 10.1145/2460625.2460709

Food Provisioning and the Domestic Food Handling Practices of the Over 60s in the North East of England

Helen Elizabeth Kendall

PhD Thesis

Abstract: Over the last decade there has been an unexplained increase in cases of listeriosis in the UK observed almost exclusively in those aged over 60 (SSRC, 2009, ACMSF, 2009). Domestic food safety practices have been hypothesised as one contributing factor to this increase (SSRC, 2009), and this research... Over the last decade there has been an unexplained increase in cases of listeriosis in the UK observed almost exclusively in those aged over 60 (SSRC, 2009, ACMSF, 2009). Domestic food safety practices have been hypothesised as one contributing factor to this increase (SSRC, 2009), and this research was funded to explore these practices in more detail. Using the North East of England as the geographical focus for the research, a mixed method approach was chosen using a complement of traditional and innovative research methods in a two-phase approach. Phase 1 was a large-scale administered questionnaire (n=213), designed to profile independently residing older adults (aged 60+) based upon their knowledge of, and reported practices associated with, domestic food safety. Factor and cluster analyses revealed a 3-cluster solution, which provided the basis for detailed narrative typologies of the clusters which were labelled; i) ‘Independent Self- assessors’, ii) ‘Experienced Dismissers’ and iii) ‘Compliant Minimalists’. These findings highlighted the heterogeneity of the 60+ population with respect to their living and health circumstances, social networks and their food safety knowledge and behavioural practices. The risk of foodborne illness was not identified as linear with age, rather levels of vulnerability to foodborne risks varied across the cohort. Phase 2 purposively sampled 10 households from Phase 1 for an ethnographically inspired study (EIS), which took a Social Practice Theory perspective to observe domestic food handling practices. Data were generated using life-course interviews, fridge auditing including microbiological sampling, kitchen ‘go-alongs’, food purchase history, activity recognition and video documentation. In addition to confirming the findings of Phase 1, the substantive theoretical contribution of Phase 2 was the concept of ‘Independence Transitioning’. Food provisioning practices were the observed outcome of the value negotiations made by the household to adapt to the incremental changes experienced as part of the ageing process that facilitated independent living. Although food safety issues were implicit within these practices, they were not a salient factor within food provisioning or handling. This was therefore concluded to compound their risk of contracting illness as a result of foodborne disease.

DOI: https://theses.ncl.ac.uk/dspace/bitstream/10443/1925/1/Kendall,%20H.%20E.%2013.pdf

Wearable Recognition System for Physical Activities

Khan, A.M. Lawo, M. Homer, P.

Intelligent Environments (IE), 2013 9th International Conference on

Abstract: Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a personal activity recognition system that is practical, reliable, and can be used for health... Physical activity is a major part of a user's context for wearable computing applications. The system should be able to acquire the user's physical activities by using body worn sensors. We want to develop a personal activity recognition system that is practical, reliable, and can be used for health-care related applications. We propose to use the axivity device [1] which is a ready-made, light weight, small and easy to use device for identifying basic physical activities like lying, sitting, walking, standing, cycling, running, ascending and descending stairs using decision tree classifier. In this paper, we present an approach to build a system that exhibits this property and provides evidence based on data for 8 different activities collected from 12 different subjects. Our results indicate that the system has a good accuracy rate.

DOI: 10.1109/IE.2013.50

Using the Axivity AX3 accelerometer in older people - a validation study

Marion E T McMurdo

East of Scotland Research Ethics Service REC 2

Automatic assessment of problem behavior in individuals with developmental disabilities

Ploetz, T., Hammerla, N.Y., Rozga, A., Reavis, A., Call, N., & Abowd, G. D.

2012 ACM Conference on Ubiquitous Computing (pp. 391-400). ACM.

Abstract: Severe behavior problems of children with developmental disabilities often require intervention by specialists. These specialists rely on direct observation of the behavior, usually in a controlled clinical environment. In this paper, we present a technique for using on-body accelerometers to assist... Severe behavior problems of children with developmental disabilities often require intervention by specialists. These specialists rely on direct observation of the behavior, usually in a controlled clinical environment. In this paper, we present a technique for using on-body accelerometers to assist in automated classification of problem behavior during such direct observation. Using simulated data of episodes of severe behavior acted out by trained specialists, we demonstrate how machine learning techniques can be used to segment relevant behavioral episodes from a continuous sensor stream and to classify them into distinct categories of severe behavior (aggression, disruption, and self-injury). We further validate our approach by demonstrating it produces no false positives when applied to a publicly accessible dataset of activities of daily living. Finally, we show promising classification results when our sensing and analysis system is applied to data from a real assessment session conducted with a child exhibiting problem behaviors.

DOI: 10.1145/2370216.2370276

Accelerometer localization in the view of a stationary camera

Stein, S., & McKenna, S. J.

Computer and Robot Vision (CRV), 2012 Ninth Conference on (pp. 109-116). IEEE.

Abstract: This paper addresses the problem of localizing an accelerometer in the view of a stationary camera as a first step towards multi-model activity recognition. This problem is challenging as accelerometers are visually occluded, they measure proper acceleration including effects of gravity and their or... This paper addresses the problem of localizing an accelerometer in the view of a stationary camera as a first step towards multi-model activity recognition. This problem is challenging as accelerometers are visually occluded, they measure proper acceleration including effects of gravity and their orientation is unknown and changes over time relative to camera viewpoint. Accelerometers are localized by matching acceleration estimated along visual point trajectories to accelerometer data. Trajectories are constructed from point feature tracking (KLT) and by grid sampling from a dense flow field. We also construct 3D trajectories with visual depth information. The similarity between accelerometer data and a trajectory is computed by counting the number of frames in which the norms of accelerations in both sequences exceed a threshold. For quantitative evaluation we collected a challenging dataset consisting of video and accelerometer data of a person preparing a mixed salad with accelerometer-equipped kitchen utensils. Trajectories from dense optical flow yielded a higher localization accuracy compared to point feature tracking.

DOI: 10.1109/CRV.2012.22

The French kitchen: task-based learning in an instrumented kitchen

Hooper, Clare J., Anne Preston, Madeline Balaam, Paul Seedhouse, Daniel Jackson, Cuong Pham, Cassim Ladha, Karim Ladha, Thomas Ploetz, and Patrick Olivier.

2012 ACM Conference on Ubiquitous Computing, pp.193-202. ACM, 2012.

Abstract: Ubiquitous computing technologies have traditionally striven to augment objects and the environment with sensing capabilities to enable them to respond appropriately to the needs of the individuals in the environment. This paper considers how such technologies might be harnessed to support language ... Ubiquitous computing technologies have traditionally striven to augment objects and the environment with sensing capabilities to enable them to respond appropriately to the needs of the individuals in the environment. This paper considers how such technologies might be harnessed to support language learning, and specifically Task-Based Learning (TBL). Task-Based Learning (TBL) involves doing meaningful tasks in a foreign language, emphasising the language's use in practice. TBL is seen as a highly engaging and motivating approach to learning a language, but is difficult to do in the classroom. Here, learners typically engage in activities that only simulate 'real-world' tasks, and as such only rehearse language use, rather than applying the language in practice. In this paper, we explore how an instrumented, context-aware environment whose design is grounded in pedagogical principles can support TBL. We present the French Kitchen, an instrumented kitchen for English speakers who are learning French, and describe a 46-participant evaluation of the kitchen. Based on the evaluation, we provide a set of design recommendations for those building instrumented systems for TBL.

DOI: 10.1145/2370216.2370246

Accelerating insight into food safety practices

Kendall, H., Ladha, C.

8th International Social Science Methodology Conference of the International Sociological Association's Research Committee on Logic and Methodology in Sociology. Sydney, Australia 2011.

Abstract: Abstract Background: Illness as a consequence of food-borne disease is a global concern (Redmond and Griffith, 2009). Taking a UK centric perspective, an increased prevalence of Listeria has been observed, that has been exclusively isolated to the over 60s population (SSRC, 2009, ACMSF, 2009). Conc... Abstract Background: Illness as a consequence of food-borne disease is a global concern (Redmond and Griffith, 2009). Taking a UK centric perspective, an increased prevalence of Listeria has been observed, that has been exclusively isolated to the over 60s population (SSRC, 2009, ACMSF, 2009). Conclusions of the Social Science Research Committee (SSRC) (2009) highlight the critical role that domestic food-safety and the kitchen environment has in this increase. However, there is limited insight into the consumer domestic food-safety practices in this vulnerable group. Domestic food-provisioning practices are mundane and habitual, being tacitly enacted with little conscious thought by those involved (Backett-Milburn et al. 2010). Methods of enquiry are therefore required to disentangle complex interrelated kitchen behaviours, whilst being sympathetic to the sensitivities of the study cohort. Although traditional observational techniques are valuable, these ethnographic observations and extensive use of video equipment can be both daunting and demanding for older participants, and present logistical problems both technically and socially for researchers. This paper explores the use of accelerometers and activity recognition (AR) techniques for quantitatively evaluating home-based levels of kitchen activity and practice interaction in the over 60s. Methodology This study involved instrumenting 10 domestic kitchens with AX3 (Openmovement, 2011) sensors and a video camera which supported in-depth interviewing related to the 4 'C''s' of food safety:- cooking, cleaning, cross-contamination and cooling. The AX3 sensors developed by Ladha et al (2011) were overmolded in food safe plastic, making them suitable for use within the kitchen environment. Sensors were configured to continuously log tri-axial acceleration and strategically placed in a range of locations in the kitchen including inside the fridge, with each deployment lasting 14 days. A recorded video was used to annotate the accelerometer sensor data for events using the ELAN (LAT, 2008) tool. Once annotated, 50% of the accelerometer data was subjected to a principal component analysis (PCA) to identify classifiers, which was then subsequently used to train a K-Nearest Neighbour (KNN) algorithm. The remaining 50% of the gathered data was then passed through the KNN and the output compared to the hand ELAN based annotations. Results from the process indicate a sensitivity of 95.5%, a specificity of 100% and an accuracy of 97.7%. This study demonstrates the successful implementation of accelerometers to reliably and unobtrusively evaluate levels of kitchen activity, without the need for constant and intensive observation. Contributions of AR as part of a toolkit of methods for understanding domestic-food safety behaviours and the merits for providing a complimentary layer of data to the traditional visual and the discursive were evaluated. Results of this study are presented drawing on the post-hoc reflections of both researchers and participants to evaluate the suitability of such technologies for this age cohort.

DOI: Poster

Assessing motor performance with PCA

Hammerla, N., Thomas Ploetz, Peter Andras, and Patrick Olivier.

International Workshop on Frontiers in Activity Recognition using Pervasive Sensing, pp. 18-23. 2011.

Abstract: Information about the motor performance, i.e. how well an activity is performed, is valuable information for a variety of novel applications in Activity Recognition (AR). Its as- sessment represents a significant challenge, as requirements depend on the specific application. We develop an approach t... Information about the motor performance, i.e. how well an activity is performed, is valuable information for a variety of novel applications in Activity Recognition (AR). Its as- sessment represents a significant challenge, as requirements depend on the specific application. We develop an approach to quantify one aspect that many domains share – the ef- ficiency of motion – that has implications for signals from body-worn or pervasive sensors, as it influences the inherent complexity of the recorded multi-variate time-series. Based on the energy distribution in PCA we infer a single, nor- malised metric that is intimately linked to signal complexity and allows comparison of (subject-specific) time-series. We evaluate the approach on artificially distorted signals and apply it to a simple kitchen task to show its applicability to real-life data streams

DOI: Workshop

Towards a pervasive kitchen infrastructure for measuring cooking competence

Wagner, J., A.van Halteren, J. Hoonhout, T. Ploetz, C. Pham, P. Moynihan, D.Jackson, C. Ladha, K. Ladha, and P. Olivier.

Pervasive Computing Technologies for Healthcare (PervasiveHealth), 2011 5th International Conference on, pp. 107-114. IEEE, 2011.

Abstract: Research has demonstrated that a lack of cooking competence can be a significant barrier to healthier eating. We present two studies from which we develop a set of requirements for a pervasive sensor infrastructure that will enable our Ambient Kitchen environment to measure cooking competence in an ... Research has demonstrated that a lack of cooking competence can be a significant barrier to healthier eating. We present two studies from which we develop a set of requirements for a pervasive sensor infrastructure that will enable our Ambient Kitchen environment to measure cooking competence in an unobtrusive manner. From the first study we derive key characteristics and potentially measurable aspects of cooking competence. This study also led to the specification and design of a pervasive sensor infrastructure comprising of a set of kitchen utensils equipped with custom-made wireless accelerometers. The second study reports our initial findings from the use of the sensor infrastructure and demonstrates its potential to measure key indicators of cooking competence. Our studies provide initial evidence that cooking competence can be measured automatically using our proposed pervasive kitchen infrastructure.

DOI: ISBN:978-1-61284-767-2

Gestural Musical Affordances

Tanaka, A., Altavilla, A., & Spowage, N.

Proc. SMC (2012): 318-325.

Abstract: This paper is a comparative study of gestural interaction with musical sound, designed to gain insight into the no- tion of musical affordance on interactive music systems. We conducted an interview base user study trialing three accelerometer based devices, an iPhone, a Wii-mote, and an Axivity Wax... This paper is a comparative study of gestural interaction with musical sound, designed to gain insight into the no- tion of musical affordance on interactive music systems. We conducted an interview base user study trialing three accelerometer based devices, an iPhone, a Wii-mote, and an Axivity Wax prototype, with four kinds of musical sound, including percussion, stringed instruments, and voice recordings. The accelerometers from the devices were mapped to computer based sound synthesis parame- ters. By using consistent mappings across different source sounds, and performing them from the three different devices, users experienced forms of physical, sonic, and cultural affordance, that combine to form what we term musical affordance.

Activity classification using a single chest mounted tri-axial accelerometer.

Godfrey, A., Bourke, A. K., Olaighin, G. M., Van De Ven, P., & Nelson, J

Medical engineering & physics, 33(9), 1127-1135.

Abstract: Accelerometer-based activity monitoring sensors have become the most suitable means for objective assessment of mobility trends within patient study groups. The use of minimal, low power, IC (integrated circuit) components within these sensors enable continuous (long-term) monitoring which provides ... Accelerometer-based activity monitoring sensors have become the most suitable means for objective assessment of mobility trends within patient study groups. The use of minimal, low power, IC (integrated circuit) components within these sensors enable continuous (long-term) monitoring which provides more accurate mobility trends (over days or weeks), reduced cost, longer battery life, reduced size and weight of sensor. Using scripted activities of daily living (ADL) such as sitting, standing, walking, and numerous postural transitions performed under supervised conditions by young and elderly subjects, the ability to discriminate these ADL were investigated using a single tri-axial accelerometer, mounted on the trunk. Data analysis was performed using Matlab® to determine the accelerations performed during eight different ADL. Transitions and transition types were detected using the scalar (dot) product technique and vertical velocity estimates on a single tri-axial accelerometer was compared to a proven discrete wavelet transform method that incorporated accelerometers and gyroscopes. Activities and postural transitions were accurately detected by this simplified low-power kinematic sensor and activity detection algorithm with a sensitivity and specificity of 86-92% for young healthy subjects in a controlled setting and 83-89% for elderly healthy subjects in a home environment.

DOI: 10.1016/j.medengphy.2011.05.002

Slice & dice: Recognizing food preparation activities using embedded accelerometers

Pham, Cuong, and Patrick Olivier.

Ambient Intelligence, pp. 34-43. Springer Berlin Heidelberg, 2009.

Abstract: Within the context of an endeavor to provide situated support for people with cognitive impairments in the kitchen, we developed and evaluated classifiers for recognizing 11 actions involved in food preparation. Data was collected from 20 lay subjects using four specially designed kitchen utensils i... Within the context of an endeavor to provide situated support for people with cognitive impairments in the kitchen, we developed and evaluated classifiers for recognizing 11 actions involved in food preparation. Data was collected from 20 lay subjects using four specially designed kitchen utensils incorporating embedded 3-axis accelerometers. Subjects were asked to prepare a mixed salad in our laboratory-based instrumented kitchen environment. Video of each subject's food preparation activities were independently annotated by three different coders. Several classifiers were trained and tested using these features. With an overall accuracy of 82.9% our investigation demonstrated that a broad set of food preparation actions can be reliably recognized using sensors embedded in kitchen utensils.

DOI: 10.1007/978-3-642-05408-2_4