Priorities when designing a service-focused delivery model for mobility devices: a systematic review.

PURPOSE: Throughout the world, mobility devices are usually distributed using product-based business models, where a device is provided to a user, and serviced or replaced when the user returns to the clinic with an issue. Moving to a service-based business model can provide continuous and customised support for the user, and provide the clinicians and manufacturers with better data to base their decisions on. This study reviews papers on assistive technology service-based business models and considerations in designing such a model to optimise economic and social value. It then applies the findings to the mobility device space. METHOD: A systematic literature search was undertaken in PubMed, Web of Science, and OVID databases to analyse studies that discuss service delivery models used to provide assistive products. Inductive thematic analysis determined the themes, facilitators and barriers associated with providing a service. Findings were applied to mobility device service provision. RESULTS AND CONCLUSION: Themes from the 29 relevant papers were grouped into four categories: Access (affordability/availability/education), Utility (customisability/usability/adaptability), Integrity (quality/sustainability/impact), and Compliance (policy/privacy/security). The most common themes were customisability, affordability, availability, and education. There is a need for service-based delivery models to replace conventional product-based models, and many considerations to optimise their design. No publications discussed the design and implementation of a service-based model for mobility device provision that uses modern sensors, software and other digital technologies to optimise the service. Service-based models that use modern digital technologies are new for the mobility device field, but much can be learnt from other fields.

Service-based business models that make use of modern digital technologies are likely to improve ongoing individual rehabilitation, but they are new for the mobility device field and currently lack research and evidence-based practice.The systematic review found that modern digital technologies like sensors, apps, and AI might be useful for providing ongoing support and more personalised rehabilitation for users of assistive products.To provide ongoing support for end-users, a successful design of service-based business model for assistive products should be accessible, both physically and financially, as well as easy to customise and adapt over time.

Characteristics of a protocol to collect objective physical activity/sedentary behaviour data in a large study: Seniors USP (understanding sedentary patterns).

The Seniors USP study measured sedentary behaviour (activPAL3, 9 day wear) in older adults. The measurement protocol had three key characteristics: enabling 24-hour wear (monitor location, waterproofing); minimising data loss (reducing monitor failure, staff training, communication); and quality assurance (removal by researcher, confidence about wear). Two monitors were not returned; 91% (n=700) of returned monitors had 7 valid days of data. Sources of data loss included monitor failure (n=11), exclusion after quality assurance (n=5), early removal for skin irritation (n=8) or procedural errors (n=10). Objective measurement of physical activity and sedentary behaviour in large studies requires decisional trade-offs between data quantity (collecting representative data) and utility (derived outcomes that reflect actual behaviour).

Upper limb activity in myoelectric prosthesis users is biased towards the intact limb and appears unrelated to goal-directed task performance.

Studies of the effectiveness of prosthetic hands involve assessing user performance on functional tasks, typically collected in the lab, sometimes combined with self-report of real-world use. In this paper we compare real-world upper limb activity between a group of 20 myoelectric prosthesis users and 20 anatomically intact adults. Activity was measured from wrist-worn accelerometers over a 7-day period. The temporal patterns in upper limb activity are presented and the balance of activity between the two limbs quantified. We also evaluated the prosthesis users' performance on a goal-directed task, characterised using measures including task success rate, completion time, gaze behaviour patterns, and kinematics (e.g. variability and patterns in hand aperture). Prosthesis users were heavily reliant on their intact limb during everyday life, in contrast to anatomically intact adults who demonstrated similar reliance on both upper limbs. There was no significant correlation between the amount of time a prosthesis was worn and reliance on the intact limb, and there was no significant correlation between either of these measures and any of the assessed kinematic and gaze-related measures of performance. We found participants who had been prescribed a prosthesis for longer to demonstrate more symmetry in their overall upper limb activity, although this was not reflected in the symmetry of unilateral limb use. With the exception of previously published case studies, this is the first report of real world upper limb activity in myoelectric prosthesis users and confirms the widely held belief that users are heavily reliant on their intact limb.

Comparison of single- and dual-monitor approaches to differentiate sitting from lying in free-living conditions.

High levels of sedentary time have been detrimentally linked to health outcomes. Differentiating sitting from lying may help to further understand the mechanisms associated with these health impacts. This study compares the inter-method agreement between the "single-monitor" method (thigh-worn activPAL3TM ) and a more robustly validated "dual-monitor" method (trunk and thigh-worn activPAL3TM ) in their classifications of sitting and lying under free-living conditions. Thirty-five participants (20-50 years) wore two activity monitors (thigh and trunk) for 24 hours. Total time spent lying and sitting was calculated for both methods, and agreement was determined using ICC and Bland-Altman methods. As there was no gold standard, further data were collected from five participants during structured activities that were designed to challenge classification, to better understand any disagreement between the methods. ICCs were 0.81 for sitting time and 0.64 for lying time. The single-monitor method detected less lying time than the dual-monitor method, with a mean difference of -25 minutes (95% agreement limits: -172 to 221 minutes), including three cases with extreme disagreement (mostly in daytime lying classification). The additional data collection suggested a major source of disagreement was failure of the single-monitor method to identify lying that involved no rotation around the longitudinal axis. In conclusion, there was some agreement between the single- and dual-monitor estimates of lying time under free-living conditions, but measures were not interchangeable. The main disagreement was in how the methods classified daytime lying and lying tasks involving no lateral movement. Both methods yield promise for measuring time in bed.

Time spent in sedentary posture is associated with waist circumference and cardiovascular risk.

BACKGROUND: The relationship between metabolic risk and time spent sitting, standing and stepping has not been well established. The present study aimed to determine associations of objectively measured time spent siting, standing and stepping, with coronary heart disease (CHD) risk. METHODS: A cross-sectional study of healthy non-smoking Glasgow postal workers, n=111 (55 office workers, 5 women, and 56 walking/delivery workers, 10 women), who wore activPAL physical activity monitors for 7 days. Cardiovascular risks were assessed by metabolic syndrome categorisation and 10-year PROCAM (prospective cardiovascular Munster) risk. RESULTS: Mean (s.d.) age was 40 (8) years, body mass index 26.9 (3.9) kg m-2 and waist circumference 95.4 (11.9) cm. Mean (s.d.) high-density lipoprotein cholesterol (HDL cholesterol) 1.33 (0.31), low-density lipoprotein cholesterol 3.11 (0.87), triglycerides 1.23 (0.64) mmol l-1 and 10-year PROCAM risk 1.8 (1.7)%. The participants spent mean (s.d.) 9.1 (1.8) h per day sedentary, 7.6 (1.2) h per day sleeping, 3.9 (1.1) h per day standing and 3.3 (0.9) h per day stepping, accumulating 14 708 (4984) steps per day in 61 (25) sit-to-stand transitions per day. In univariate regressions-adjusting for age, sex, family history of CHD, shift worked, job type and socioeconomic status-waist circumference (P=0.005), fasting triglycerides (P=0.002), HDL cholesterol (P=0.001) and PROCAM risk (P=0.047) were detrimentally associated with sedentary time. These associations remained significant after further adjustment for sleep, standing and stepping in stepwise regression models. However, after further adjustment for waist circumference, the associations were not significant. Compared with those without the metabolic syndrome, participants with the metabolic syndrome were significantly less active-fewer steps, shorter stepping duration and longer time sitting. Those with no metabolic syndrome features walked >15 000 steps per day or spent >7 h per day upright. CONCLUSIONS: Longer time spent in sedentary posture is significantly associated with higher CHD risk and larger waist circumference.

Seasonal variation in the distribution of daily stepping in 11-13 year old school children.

PURPOSE: Seasonality studies in adolescent's physical activity (PA) tend to report total PA (e.g. steps/day) rather than more specific detail such as steps/hour. This study compared the detailed changes in PA between seasons. METHODS: Thirty three adolescents (baseline age 12.2 ± 0.3y) wore the activPAL activity monitor for 8 days on two occasions. RESULTS: Steps/day were higher in summer (Mdn = 12,879) than winter (Mdn = 10,512), p<.001. Steps/hour were significantly higher in summer compared to winter between 17:00 and 21:00 (p<. 044). No steps/day differences were found between boys and girls at either time point (p>.05), however, boys had significantly higher step counts in summer between '13:00-14:00' (p=.023), '19:00-20:00' (p=.032) and '20:00-21:00' (p=.023). CONCLUSION: Total steps/day masked sex differences within specific hours of the day, particularly evening times. Detailed daily patterns of PA are required to fully understand differences between sexes and across seasons.

Free-living physical activity as a novel outcome measure in patients with intermittent claudication.

OBJECTIVE: To develop a method of event-based analysis that quantifies the fragmented nature of walking bouts in individuals with intermittent claudication [IC] and compare outcomes with age and gender-matched healthy controls. DESIGN: Cross-sectional. MATERIALS: The activPAL™ physical activity monitor. METHODS: 7-day physical activity patterns were compared between individuals with IC (n = 30) and controls matched for age and gender (n = 30). The ratio of the number of walking events to upright events was calculated to provide an event-based claudication index (EBCI) that represented the fragmented nature of walking bouts commonly reported in those with IC. RESULTS: Individuals with IC had a greater EBCI than age matched controls indicating a more fragmented walking pattern (5.8 ± 2.0 vs. 7.7 ± 3.1, p < 0.01). The difference between groups was more pronounced when the EBCI was calculated from upright events that included >400 steps (23.4 ± 11.3 vs. 35.8 ± 14.2, p < 0.01). CONCLUSION: The classic fragmented stop/start walking pattern universally described by individuals with IC can be quantified using the EBCI. This method of measurement potentially provides a novel method of assessing the effectiveness of clinical interventions for this patient group.

The prevalence of upright non-stepping time in comparison to stepping time in 11-13 year old school children across seasons.

Evidence suggests that behaviours such as standing are beneficial for our health. Unfortunately, little is known of the prevalence of this state, its importance in relation to time spent stepping or variation across seasons. The aim of this study was to quantify, in young adolescents, the prevalence and seasonal changes in time spent upright and not stepping (UNSt(time)) as well as time spent upright and stepping (USt(time)), and their contribution to overall upright time (U(time)). Thirty-three adolescents (12.2 ± 0.3 y) wore the activPAL activity monitor during four school days on two occasions: November/December (winter) and May/June (summer). UNSt(time) contributed 60% of daily U(time) at winter (Mean = 196 min) and 53% at summer (Mean = 171 min); a significant seasonal effect, p < 0.001. USt(time) was significantly greater in summer compared to winter (153 min versus 131 min, p < 0.001). The effects in UNSt(time) could be explained through significant seasonal differences during the school hours (09:00-16:00), whereas the effects in USt(time) could be explained through significant seasonal differences in the evening period (16:00-22:00). Adolescents spent a greater amount of time upright and not stepping than they did stepping, in both winter and summer. The observed seasonal effects for both UNSt(time) and USt(time) provide important information for behaviour change intervention programs.

Development and validation of a physical activity monitor for use on a wheelchair.

STUDY DESIGN: Keeping physically active is important for people who mobilize using a wheelchair. However, current tools to measure physical activity in the wheelchair are either not validated or limited in their application. The purpose of this study was to develop and validate a monitoring system to measure wheelchair movement. METHODS: The system developed consisted of a tri-axial accelerometer placed on the wheel of a wheelchair and an analysis algorithm to interpret the acceleration signals. The two accelerometer outputs in the plane of the wheel were used to calculate the angle of the wheel. From this, outcome measures of wheel revolutions, absolute angle and duration of movement were derived and the direction of movement (forwards or backwards) could be distinguished. Concurrent validity was assessed in comparison with video analysis in 14 people with spinal cord injury using their wheelchair on an indoor track and outdoor wheelchair skills course. Validity was assessed using intraclass correlation coefficients (ICC(2,1)) and Bland-Altman plots. RESULTS: The monitoring system demonstrated excellent validity for wheel revolutions, absolute angle and duration of movement (ICC(2,1)>0.999, 0.999, 0.981, respectively) in both manual and powered wheelchairs, when the wheelchair was propelled forwards and backwards, and for movements of various durations. CONCLUSION: This study has found this monitoring system to be an accurate and objective tool for measuring detailed information on wheelchair movement and maneuvering regardless of the propulsion technique, direction and speed.

Methods for objective measure, quantification and analysis of sedentary behaviour and inactivity.

The purpose of this study was to develop and test a generic technique to robustly quantify the pattern of sedentary behaviour from objective records. The technique was applied to four groups of subjects: a healthy group with an active occupation (N=54), a healthy group with a sedentary occupation (N=53), a group of subjects with chronic low back pain (N=5) and a group of subjects with chronic fatigue syndrome (N=14). This study presents the first evidence that bouts of sedentary activity are power law distributed. Results showed that there was no significant difference in total sedentary time between the groups, however, the patterns of accumulation of sedentary time were significantly different for the groups. Sedentary groups accumulated their total sedentary time from a small number of longer sedentary bouts. Active groups tended to break their sedentary time into a greater number of shorter bouts. This suggests that the power law exponent alpha and the GINI index G, used to describe the pattern of accumulation of sedentary time, could be used to evaluate and quantify sedentary behaviour.

Objective assessment of mobility of the spinal cord injured in a free-living environment.

STUDY DESIGN: An exploratory study of the practicality and feasibility of an instrument. OBJECTIVES: To adapt an activity monitor for use on a wheelchair to assess long-term mobility in a free-living environment in the spinal cord injury (SCI) population, and to explore the utility of the data collected. SETTING: Glasgow, UK. METHODS: An activity monitor was adapted for use on a wheelchair wheel. The monitor was used to assess, for 1 week, the wheelchair mobility of seven participants with SCI who only used a wheelchair. In conjunction with a second monitor on the thigh the mobility of seven participants with SCI who used a wheelchair and upright mobility, and five healthy non-wheelchair users, were assessed for 1 day. RESULTS: The adapted monitor collected 1260 h of data and was suitable for use on both manual and electric wheelchairs. During 1 week, participants with SCI who only used a wheelchair spent between 4 and 13 h moving in the wheelchair, covering a distance of between 7 and 28 km. Distinct differences in mobility were shown between participants with an SCI and non-wheelchair users. The differences in time spent in mobility activities between the groups of participants with SCI were smaller. CONCLUSIONS: The system was successfully used in this group of participants with SCI, and could provide useful information on the mobility of people with SCI in a free-living environment.

Continuous monitoring of upper-limb activity in a free-living environment: a validation study.

Monitoring upper-limb activity in a free-living environment is important for the evaluation of rehabilitation. This study is a validation of the Strathclyde Upper-Limb Activity Monitor (SULAM) which records the vertical movement and position of each wrist, and assesses bimanual movement. Agreement between the SULAM and two independent video observers was assessed using interclass correlation coefficients (ICC) and the Bland and Altman method. Concurrent validity was very good for movement of each upper-limb (ICC > 0.9), and good for the vertical position of the wrist (ICC > 0.8 for wrist positions below the shoulder, ICC > 0.6 otherwise). The ICC was good (>0.8) for bimanual movement, however the SULAM systematically underreported this by approximately 15%. The SULAM could be a useful tool to assess upper-limb activity of clinical populations in their usual environment.

The validation of a novel activity monitor in the measurement of posture and motion during everyday activities.

BACKGROUND: Accurate measurement of physical activity patterns can be used to identify sedentary behaviour and may facilitate interventions aimed at reducing inactivity. OBJECTIVE: To evaluate the activPAL physical activity monitor as a measure of posture and motion in everyday activities using observational analysis as the criterion standard. METHODS: Wearing three activPAL monitors, 10 healthy participants performed a range of randomly assigned everyday tasks incorporating walking, standing and sitting. Each trial was captured on a digital camera and the recordings were synchronised with the activPAL. The time spent in different postures was visually classified and this was compared with the activPAL output. RESULTS: Intraclass correlation coefficients (ICC 2,1) for interdevice reliability ranged from 0.79 to 0.99. Using the Bland and Altman method, the mean percentage difference between the activPAL monitor and observation for total time spent sitting was 0.19% (limits of agreement -0.68% to 1.06%) and for total time spent upright was -0.27% (limits of agreement -1.38% to 0.84%). The mean difference for total time spent standing was 1.4% (limits of agreement -6.2% to 9.1%) and for total time spent walking was -2.0% (limits of agreement -16.1% to 12.1%). A second-by-second analysis between observer and monitor found an overall agreement of 95.9%. CONCLUSION: The activPAL activity monitor is a valid and reliable measure of posture and motion during everyday physical activities.

The validity and reliability of a novel activity monitor as a measure of walking.

BACKGROUND: The accurate measurement of physical activity is crucial to understanding the relationship between physical activity and disease prevention and treatment. OBJECTIVE: The primary purpose of this study was to investigate the validity and reliability of the activPAL physical activity monitor in measuring step number and cadence. METHODS: The ability of the activPAL monitor to measure step number and cadence in 20 healthy adults (age 34.5+/-6.9 years; BMI 26.8+/-4.8 (mean+/-SD)) was evaluated against video observation. Concurrently, the accuracy of two commonly used pedometers, the Yamax Digi-Walker SW-200 and the Omron HJ-109-E, was compared to observation for measuring step number. Participants walked on a treadmill at five different speeds (0.90, 1.12, 1.33, 1.56, and 1.78 m/s) and outdoors at three self selected speeds (slow, normal, and fast). RESULTS: At all speeds, inter device reliability was excellent for the activPAL (ICC (2,1)> or =0.99) for both step number and cadence. The absolute percentage error for the activPAL was <1.11% for step number and cadence regardless of walking speed. The accuracy of the pedometers was adversely affected by slow walking speeds. CONCLUSION: The activPAL monitor is a valid and reliable measure of walking in healthy adults. Its accuracy is not influenced by walking speed. The activPAL may be a useful device in sports medicine.

Measuring continuous real-world upper-limb activity.

The Strathclyde Upper-Limb Activity Monitor (SULAM) was used to assess real-world upper-limb activity. The SULAM consists of an electro-hydraulic activity-sensor which measures the vertical displacement of the wrist in relation to the shoulder. The aims of this study were to obtain a profile of upper-limb activity in two different populations (able-bodied participants and stroke patients) Ten able-bodied volunteers and ten stroke patients-wore the SULAM while performing their everyday activities. The outcome measures were movement time, its distribution in five vertical ranges, bimanual and unimanual movement time. There was a difference in the use of both upper-limbs for both groups, favouring the dominant/unaffected arm. This difference was only in two of the five ranges (chest to shoulder and shoulder to head for able-bodied participants; waist to chest and chest to shoulder for stroke patients). Bimanual movement was greater than unimanual movement for able-bodied participants whereas unimanual movement was greater than bimanual movement for stroke patients.

Contractures in the post-stroke wrist: a pilot study of its time course of development and its association with upper limb recovery.

BACKGROUND: Contractures are common in a stroke population, yet there is little information on the time course of development. OBJECTIVES: Investigate quantitatively changes associated with contracture formation in an acute stroke population. STUDY DESIGN: Longitudinal study on 22 subjects who were 2-4 weeks post stroke. OUTCOME MEASURES: Contractures were assessed by quantifying the resting posture, resistance to passive movement and passive range of movement. Upper limb function was measured using the Action Research Arm Test and the Nine-Hole Peg Test. Active range of extension, wrist extension strength (isometric), grip strength and neglect were also measured. REPEATED MEASURES: Following an initial assessment, repeated measurements were taken at 4, 8, 20 and 32 weeks after recruitment. RESULTS: Two distinct subgroups, one capable of some functional movement (F group; 8 subjects) and another which was not (NF group; 14 subjects), were identified at the start of the study. The NF group showed changes associated with contracture formation at the wrist, i.e., reduction in the passive range of movement, an increase in resistance to passive movement and a worsening of the flexion posture. Changes were observed from the time of recruitment even though neglect improved. The F group showed improvements in upper limb function and there was no evidence to support contracture formation. CONCLUSIONS: Subjects most prone to contracture formation were those who showed no signs of early functional recovery (2-4 weeks after the stroke). Changes consistent with adaptive shortening were seen from week 4 of the study period.

Therapeutic effects of functional electrical stimulation of the upper limb of eight children with cerebral palsy.

Functional electrical stimulation (FES) of the upper limb has been used for patients with a variety of neurological conditions, although few studies have been conducted on its use on the upper limb of children with cerebral palsy (CP). The aim of this study was to investigate the effect of cyclic FES on the wrist extensor muscles of a group of eight children (five boys, three girls) with hemiplegic CP (mean age 10 years). The study design involved a baseline (3 weeks), treatment (6 weeks), and follow-up (6 weeks). FES was applied for 30 minutes daily during the treatment period of the study. Improvements in hand function (p < or = 0.039) and active wrist extension (p = 0.031) were observed at the end of the treatment period. These improvements were largely maintained until the end of the follow-up period. No significant change was observed in the measurements of wrist extension moment during the treatment period (p = 0.274). Hand function in this group of children improved after they were exposed to FES of wrist extensor muscles. This suggests that FES could become a useful adjunct therapy to complement existing management strategies available for this patient population.

The effects of knee and ankle flexion on ground clearance in paraplegic gait.

OBJECTIVE: To investigate the effects of knee flexion and ankle dorsiflexion on ground clearance during the swing phase of paraplegic gait.BACKGROUND. Limitations of currently available walking orthoses are high energy consumption and upper limb loading. Knee flexion in the swing phase has been suggested as a means of reducing these.METHODS. Kinematic data of paraplegic gait in two currently available orthoses were used to simulate the effects of knee flexion and ankle dorsiflexion on the swing foot ground clearance. This was used to validate a mathematical model of a simple ideal gait that was also developed.RESULTS. It was shown that the implementation of knee flexion alone leads to a loss or no change in ground clearance. Implementing knee flexion and ankle dorsiflexion can be used to increase ground clearance.CONCLUSION. Flexion at the knee and ankle during the swing phase can potentially be used to allow a reduction in compensatory mechanisms by easing swing foot ground clearance. RelevanceWalking orthoses are valuable in the clinical management of paraplegia, providing both physiological and psychological benefits. Functional improvements can only serve to encourage their greater usage.

The functional use of the reciprocal hip mechanism during gait for paraplegic patients walking in the Louisiana State University reciprocating gait orthosis.

Reciprocally linked orthoses used for paraplegic walking have some form of linkage between the two hip joints. It has been assumed that flexion of the swinging leg is driven by extension of the stance leg. The aims of this study were to investigate the moments generated around the hip joint by the two cables in a Louisiana State University Reciprocating Gait Orthosis (LSU-RGO). Six (6) subjects were recruited from the Regional Spinal Injuries Centre at Southport, who were experienced RGO users. The cables were fitted with strain gauged transducers to measure cable tension. Foot switches were used to divide the gait into swing and stance phases. A minimum of 20 steps were analysed for each subject. Moments about the hip joint for each phase of gait were calculated. There were no moments generated by the front cable in 4 of the subjects. In only 2 subjects did the cable generate a moment that could assist hip flexion during the swing phase. These moments were very low and at best could only have made a small contribution to limb flexion. The back cable generated moments that clearly prevented bilateral flexion. It was concluded that the front cable, as used by these experienced RGO users, did not aid flexion of the swinging limb.