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Walking speed is a strong indicator of the health status of older people and patients. Using algorithms, the walking speed can be estimated from wearable accelerometers, which enables minimally obtrusive (longitudinal) monitoring. We evaluated the performance of two algorithms, the inverted pendulum (IP) algorithm, and a novel adaptation correcting for lateral step movement, which aimed to improve accuracy during slow walking. To evaluate robustness, we gathered data from different groups (healthy adults, elderly, and elderly patients) of volunteers (n = 159) walking under various conditions (over ground, treadmill, using walking aids) at a broad range of speeds (0.11–1.93 m/s). Both of the algorithms showed good agreement with the reference values and similar root-mean-square errors (RMSEs) for walking speeds ≥0.5 m/s, which ranged from 0.09–0.16 m/s for the different positions, in line with the results from others. However, for slower walking, RMSEs were significantly better for the new method (0.06–0.09 m/s versus 0.15–0.19 m/s). Pearson correlation improved for speeds &lt, 0.5 m/s (from 0.67–0.72 to 0.73–0.82) as well as higher speeds (0.87–0.97 to 0.90–0.98) with the new method. Overall, we found that IP(-based) walking speed estimation proved to be applicable for a variety of wearing positions, conditions and speeds, indicating its potential value for health assessment applications.

Background Recent technological developments such as wearable sensors and tablets with a mobile internet connection hold promise for providing electronic health home-based programs with remote coaching for patients following total hip arthroplasty. It can be hypothesized that such a home-based rehabilitation program can offer an effective alternative to usual care. Objective The aim of this study was to determine the effectiveness of a home-based rehabilitation program driven by a tablet app and remote coaching for patients following total hip arthroplasty. Methods Existing data of two studies were combined, in which patients of a single-arm intervention study were matched with historical controls of an observational study. Patients aged 18-65 years who had undergone total hip arthroplasty as a treatment for primary or secondary osteoarthritis were included. The intervention consisted of a 12-week home-based rehabilitation program with video instructions on a tablet and remote coaching (intervention group). Patients were asked to do strengthening and walking exercises at least 5 days a week. Data of the intervention group were compared with those of patients who received usual care (control group). Effectiveness was measured at four moments (preoperatively, and 4 weeks, 12 weeks, and 6 months postoperatively) by means of functional tests (Timed Up & Go test and the Five Times Sit-to Stand Test) and self-reported questionnaires (Hip disability and Osteoarthritis Outcome Score [HOOS] and Short Form 36 [SF-36]). Each patient of the intervention group was matched with two patients of the control group. Patient characteristics were summarized with descriptive statistics. The 1:2 matching situation was analyzed with a conditional logistic regression. Effect sizes were calculated by Cohen d. Results Overall, 15 patients of the intervention group were included in this study, and 15 and 12 subjects from the control group were matched to the intervention group, respectively. The intervention group performed functional tests significantly faster at 12 weeks and 6 months postoperatively. The intervention group also scored significantly higher on the subscales “function in sport and recreational activities” and “hip-related quality of life” of HOOS, and on the subscale “physical role limitations” of SF-36 at 12 weeks and 6 months postoperatively. Large effect sizes were found on functional tests at 12 weeks and at 6 months (Cohen d=0.5-1.2), endorsed by effect sizes on the self-reported outcomes. Conclusions Our results clearly demonstrate larger effects in the intervention group compared to the historical controls. These results imply that a home-based rehabilitation program delivered by means of internet technology after total hip arthroplasty can be more effective than usual care. Trial Registration ClinicalTrials.gov NCT03846063; https://clinicaltrials.gov/ct2/show/NCT03846063 and German Registry of Clinical Trials DRKS00011345; https://tinyurl.com/yd32gmdo

Aim Falls are a leading cause of disability in older people. Here we investigate if daily-life gait assessments are better than clinical gait assessments at discriminating between older people with and without a history of falls. Methods A total of 96 independent-living participants (age 75.5 ± 7.8) underwent sensorimotor, psychological and cognitive assessments, and the Timed Up and Go and 10-m walk tests. Participants wore a small pendant sensor device for a week in their home environment, from which the new remote assessments of daily-life gait were determined. Results During daily-life, fallers had significantly lower gait quality (lower gait endurance, higher within-walk variability and lower between-walk adaptability), but not reduced gait quantity (total steps) or gait intensity (mean cadence). In the clinic, fallers had slower Timed Up and Go, but not 10-m walk test times. After adjusting for demographics, only the daily-life assessments of gait endurance and within-walk variability remained significant. Reduced daily-life gait assessments were significantly correlated with older age, higher body mass index, multiple medications, disability, more concern about falling, poor executive function and higher physiological fall risk. Conclusions The new daily-life gait assessments were better than the clinical gait assessments at identifying fall risk in our sample of independent living older people. However, further research is required to validate these findings in other populations or those living in residential aged care. Daily-life gait was not only associated with demographics and physiological capacity, but also general health, executive function and the ability to undertake a variety of activities of daily living without excessive concern about falling. Geriatr Gerontol Int 2017; 17: 2274–2282.

BACKGROUND Mobility impairment is common in older adults and negatively influences the quality of life. Mobility level may change rapidly following surgery or hospitalization in the elderly. The timed up and go (TUG) is a simple, frequently used clinical test for functional mobility; however, TUG requires supervision from a trained clinician, resulting in infrequent assessments. Additionally, assessment by TUG in clinic settings may not be completely representative of the individual's mobility in their home environment. OBJECTIVE In this paper, we introduce a method to estimate TUG from activities detected in free-living, enabling continuous remote mobility monitoring without expert supervision. The method is used to monitor changes in mobility following total hip arthroplasty (THA). METHODS Community-living elderly (n = 239, 65-91 years) performed a standardized TUG in a laboratory and wore a wearable pendant device that recorded accelerometer and barometric sensor data for at least three days. Activities of daily living (ADLs), including walks and sit-to-stand transitions, and their related mobility features were extracted and used to develop a regularized linear model for remote TUG test estimation. Changes in the remote TUG were evaluated in orthopaedic patients (n = 15, 55-75 years), during 12-weeks period following THA. MAIN RESULTS In leave-one-out-cross-validation (LOOCV), a strong correlation (ρ = 0.70) was observed between the new remote TUG and standardized TUG times. Test-retest reliability of 3-days estimates was high (ICC = 0.94). Compared to week 2 post-THA, remote TUG was significantly improved at week 6 (11.7 ± 3.9 s versus 8.0 ± 1.8 s, p

BackgroundRecent developments in technology are promising for providing home-based exercise programs. ObjectiveThe objective of this study was to evaluate the feasibility and patient experience of a home-based rehabilitation program after total hip arthroplasty (THA) delivered using videos on a tablet personal computer (PC) and a necklace-worn motion sensor to continuously monitor mobility-related activities. MethodsWe enrolled 30 independently living patients aged 18-75 years who had undergone THA as a treatment for primary or secondary osteoarthritis (OA) between December 2015 and February 2017. Patients followed a 12-week exercise program with video instructions on a tablet PC and daily physical activity registration through a motion sensor. Patients were asked to do strengthening and walking exercises at least 5 days a week. There was weekly phone contact with a physiotherapist. Adherence and technical problems were recorded during the intervention. User evaluation was done in week 4 (T1) and at the end of the program (T2). ResultsOverall, 26 patients completed the program. Average adherence for exercising 5 times a week was 92%. Reasons mentioned most often for nonadherence were vacation or a day or weekend off 25% (33/134) and work 15% (20/134). The total number of technical issues was 8. The average score on the user evaluation questionnaire (range 0-5) was 4.6 at T1 and 4.5 at T2. The highest score was for the subscale “coaching” and the lowest for the subscale “sensor.” ConclusionsA home-based rehabilitation program driven by a tablet app and mobility monitoring seems feasible for THA patients. Adherence was good and patient experience was positive. The novel technology was well accepted. When the home-based rehabilitation program proves to be effective, it could be used as an alternative to formal physiotherapy. However, further research on its effectiveness is needed.

BACKGROUND Recent developments in technology are promising for providing home-based exercise programs. OBJECTIVE The objective of this study was to evaluate the feasibility and patient experience of a home-based rehabilitation program after total hip arthroplasty (THA) delivered using videos on a tablet personal computer (PC) and a necklace-worn motion sensor to continuously monitor mobility-related activities. METHODS We enrolled 30 independently living patients aged 18-75 years who had undergone THA as a treatment for primary or secondary osteoarthritis (OA) between December 2015 and February 2017. Patients followed a 12-week exercise program with video instructions on a tablet PC and daily physical activity registration through a motion sensor. Patients were asked to do strengthening and walking exercises at least 5 days a week. There was weekly phone contact with a physiotherapist. Adherence and technical problems were recorded during the intervention. User evaluation was done in week 4 (T1) and at the end of the program (T2). RESULTS Overall, 26 patients completed the program. Average adherence for exercising 5 times a week was 92%. Reasons mentioned most often for nonadherence were vacation or a day or weekend off 25% (33/134) and work 15% (20/134). The total number of technical issues was 8. The average score on the user evaluation questionnaire (range 0-5) was 4.6 at T1 and 4.5 at T2. The highest score was for the subscale “coaching” and the lowest for the subscale “sensor.” CONCLUSIONS A home-based rehabilitation program driven by a tablet app and mobility monitoring seems feasible for THA patients. Adherence was good and patient experience was positive. The novel technology was well accepted. When the home-based rehabilitation program proves to be effective, it could be used as an alternative to formal physiotherapy. However, further research on its effectiveness is needed.

Rule–based strength scaling is an easy, cheap and relatively accurate technique to personalise musculoskeletal models. This paper presents a new strength scaling approach for musculoskeletal models and validates it by maximal voluntary contractions. A heterogeneous group of 63 healthy subjects performed maximal isometric knee extensions. A multiple linear regression analysis resulted in a best–fit rule–based strength scaling equation, with age, mass, height, gender, segment masses and segment lengths as predictors. A second strength scaling equation was obtained through multiple linear regression using backwards elimination, resulting in an equation consisting of only the significant predictors: age, body mass and gender. For validation purposes, 20 newly included healthy subjects performed a maximal isometric leg–press. The newly developed strength scaling technique taking all predictors into account resulted in the most accurate predictions of muscle activities compared to alternative strength scaling methods. These techniques personalise musculoskeletal models to a larger extend. However, some applications that require more detailed personalised models, imaging might be necessary to obtain more specific individual muscle characteristics.

Goal: Wearable devices provide new ways to identify people who are at risk of falls and track long-term changes of mobility in daily life of older people. The aim of this study was to develop a wavelet-based algorithm to detect and assess quality of sit-to-stand movements with a wearable pendant device. Methods: The algorithm used wavelet transformations of the accelerometer and barometric air pressure sensor data. Detection accuracy was tested in 25 older people performing 30 min of typical daily activities. The ability to differentiate between people who are at risk of falls from people who are not at risk was investigated by assessing group differences of sensor-based sit-to-stand measurements in 34 fallers and 60 nonfallers (based on 12-month fall history) performing sit-to-stand movements as part of a laboratory study. Results: Sit-to-stand movements were detected with 93.1% sensitivity and a false positive rate of 2.9% during activities of daily living. In the laboratory study, fallers had significantly lower maximum acceleration, velocity, and power during the sit-to-stand movement compared to nonfallers. Conclusion: The new wavelet-based algorithm accurately detected sit-to-stand movements in older people and differed significantly between older fallers and nonfallers. Significance: Accurate detection and quantification of sit-to-stand movements may provide objective assessment and monitoring of fall risk during daily life in older people.

Arm activities are required for maintenance of self-care and independent living. This study aimed to investigate whether and to what extent arm activities of daily living (ADL) in chronic obstructive pulmonary disease (COPD) patients differ compared to healthy controls and the extent to which they perform arm ADL at a relatively higher upper limb muscle effort.Daily arm and leg activities were assessed using accelerometers in the home environment (COPD: n = 21, healthy: n = 24; part 1). The relative efforts of the trapezius, deltoid and biceps muscles were studied using electromyography during domestic arm ADL in a laboratory setting (COPD: n = 17, healthy: n = 15; part 2).After correction for walking time, the time spent on arm ADL was similar between COPD patients and healthy control subjects (p = 0.52), while the intensity of arm activities was lower in COPD patients (p = 0.041). In the laboratory setting, arm ADL were performed at a lower intensity by COPD patients, while the trapezius muscle effort was significantly higher during several arm ADL compared to healthy control subjects (p

Falls and physical deconditioning are two major health problems for older people. Recent advances in remote physiological monitoring provide new opportunities to investigate why walking exercise, with its many health benefits, can both increase and decrease fall rates in older people. In this paper we combine remote wearable device monitoring of daily gait with non-linear multi-dimensional pattern recognition analysis; to disentangle the complex associations between walking, health and fall rates. One week of activities of daily living (ADL) were recorded with a wearable device in 96 independent living older people prior to completing 6 months of exergaming interventions. Using the wearable device data; the quantity, intensity, variability and distribution of daily walking patterns were assessed. At baseline, clinical assessments of health, falls, sensorimotor and physiological fall risks were completed. At 6 months, fall rates, sensorimotor and physiological fall risks were re-assessed. A non-linear multi-dimensional analysis was conducted to identify risk-groups according to their daily walking patterns. Four distinct risk-groups were identified: The Impaired (93% fallers), Restrained (8% fallers), Active (50% fallers) and Athletic (4% fallers). Walking was strongly associated with multiple health benefits and protective of falls for the top performing Athletic risk-group. However, in the middle of the spectrum, the Active risk-group, who were more active, younger and healthier were 6.25 times more likely to be fallers than their Restrained counterparts. Remote monitoring of daily walking patterns may provide a new way to distinguish Impaired people at risk of falling because of frailty from Active people at risk of falling from greater exposure to situations were falls could occur, but further validation is required. Wearable device risk-profiling could help in developing more personalised interventions for older people seeking the health benefits of walking without increasing their risk of falls.

Falls are a leading cause of disability in older people. Here we investigate if daily-life gait assessments are better than clinical gait assessments at discriminating between older people with and without a history of falls.A total of 96 independent-living participants (age 75.5 ± 7.8) underwent sensorimotor, psychological and cognitive assessments, and the Timed Up and Go and 10-m walk tests. Participants wore a small pendant sensor device for a week in their home environment, from which the new remote assessments of daily-life gait were determined.During daily-life, fallers had significantly lower gait quality (lower gait endurance, higher within-walk variability and lower between-walk adaptability), but not reduced gait quantity (total steps) or gait intensity (mean cadence). In the clinic, fallers had slower Timed Up and Go, but not 10-m walk test times. After adjusting for demographics, only the daily-life assessments of gait endurance and within-walk variability remained significant. Reduced daily-life gait assessments were significantly correlated with older age, higher body mass index, multiple medications, disability, more concern about falling, poor executive function and higher physiological fall risk.The new daily-life gait assessments were better than the clinical gait assessments at identifying fall risk in our sample of independent living older people. However, further research is required to validate these findings in other populations or those living in residential aged care. Daily-life gait was not only associated with demographics and physiological capacity, but also general health, executive function and the ability to undertake a variety of activities of daily living without excessive concern about falling. Geriatr Gerontol Int 2017; 17: 2274-2282.

Background Generally, the use of a rollator improves mobility in patients with COPD. Nevertheless, not all patients benefit from its use, and many patients feel embarrassed about using it. Therefore, other walking aids are worthwhile to consider. We compared the direct effects of a "new" ambulation aid (a modern draisine) with the effects of a rollator on 6-min walk distance (6MWD) in patients with COPD. Methods Twenty-one patients with COPD performed two 6-min walk tests (6MWTs) during prerehabilitation assessment (best 6MWD: 369 ± 88 m). Additionally, two extra 6MWTs were performed on two consecutive days in random order: one time with a rollator and one time with a modern draisine. Walking pattern (n = 21) was determined using an accelerometer, and metabolic requirements (n = 10) were assessed using a mobile oxycon. Results Walking with the modern draisine resulted in a higher 6MWD compared with walking with the rollator (466 ± 189 m vs 383 ± 85 m). Moreover, patients had fewer strides (245 ± 61 vs 300 ± 49) and a greater stride length (1.89 ± 0.73 m vs 1.27 ± 0.14 m) using the modern draisine compared with the rollator (all P ≤ .001). Oxygen uptake, ventilation, heart rate, oxygen saturation, and Borg symptom scores were comparable between both walking aids. Ten percent of the patients felt embarrassed using the modern draisine compared with 19% for the rollator, and a significantly smaller proportion of patients would use the modern draisine in daily life. Conclusions The mean difference in 6MWD between a modern draisine and a rollator seems clinically relevant, with the same metabolic requirements and symptom Borg scores. Therefore, this "new" ambulation aid could be a good alternative to the rollator to improve functional exercise performance in patients with COPD. Trial registry The Netherlands National Trial Registry; No.: NTR1542; URL: www.trialregister.nl

Background Problematic activities of daily life (ADLs) can be the main reason to refer patients with chronic obstructive pulmonary disease (COPD) for pulmonary rehabilitation. To date, information on problematic ADLs and their clinical correlates in COPD remain scarce. This retrospective chart review aimed to identify the most prevalent self-reported problematic ADLs in COPD patients, determine performance and satisfaction scores of these problematic ADLs, and explore the association between 13 clinical determinants and 4 problematic ADL domains. Methods A total of 820 COPD patients entering pulmonary rehabilitation assessment were included in this retrospective study. Self-reported problematic ADLs were assessed using the Canadian Occupational Performance Measure, administered by occupational therapists in the form of a semistructured interview. Results COPD patients (59% male, age 63.6 ± 9.3 years, FEV 1 (%pred): 46.4 ± 18.4) reported 2999 problematic ADLs. The most prevalent problematic ADLs were walking (68%), stair climbing (35%), and cycling (30%). Moreover, 30% of the patients reported "not able to do any of the scored problematic ADL" and 44% were "not satisfied at all with the performance of any of the scored problematic ADL." Significant but weak associations were found between clinical determinants (eg, physical and psychosocial) and problematic ADLs. Conclusions The lack of a strong association between problematic ADLs and clinical determinants emphasizes the need for individualized assessment of these ADLs to allow tailored intervention.

Objectives: Develop algorithms to detect gait impairments remotely using data from freely worn devices during long-term monitoring. Identify statistical models that describe how gait performances are distributed over several weeks. Determine the data window required to reliably assess an increased propensity for falling. Methods: 1085 days of walking data were collected from eighteen independent-living older people (mean age 83 years) using a freely worn pendant sensor (housing a triaxial accelerometer and pressure sensor). Statistical distributions from several accelerometer-derived gait features (encompassing quantity, exposure, intensity, and quality) were compared for those with and without a history of falling. Results: Participants completed more short walks relative to long walks, as approximated by a power law. Walks less than 13.1 s comprised 50% of exposure to walking-related falls. Daily-life cadence was bimodal and step-time variability followed a log-normal distribution. Fallers took significantly fewer steps per walk and had relatively more exposure from short walks and greater mode of step-time variability. Conclusions: Using a freely worn device and wavelet-based analysis tools allowed long-term monitoring of walks greater than or equal to three steps. In older people, short walks constitute a large proportion of exposure to falls. To identify fallers, mode of variability may be a better measure of central tendency than mean of variability. A week's monitoring is sufficient to reliably assess the long-term propensity for falling. Significance: Statistical distributions of gait performances provide a reference for future wearable device development and research into the complex relationships between daily-life walking patterns, morbidity, and falls.

The reproducibility of the 6-min walking test (6MWT) needs to be more solidly studied. This study aimed to investigate the reproducibility of two 6MWTs performed on subsequent days in a large and representative sample of patients with chronic obstructive pulmonary disease (COPD), and to quantify the learning effect between the two tests, as well as its determinants. In a retrospective observational study, 1,514 patients with COPD performed two 6MWTs on subsequent days. Other measurements included body composition (dual X-ray absorptiometry), dyspnoea (Medical Research Council scale) and comorbidity (Charlson index). Although the 6MWT was reproducible (intraclass correlation coefficient = 0.93), patients walked farther in the second test (391 m, 95% CI 155-585 m versus 418 m, 95% CI 185-605 m; p

[EN] Background: Falls and fall-related injuries are a serious public health issue. Exercise programs can effectively reduce fall risk in older people. The iStoppFalls project developed an Information and Communication Technology-based system to deliver an unsupervised exercise program in older people's homes. The primary aims of the iStoppFalls randomized controlled trial were to assess the feasibility (exercise adherence, acceptability and safety) of the intervention program and its effectiveness on common fall risk factors. Methods: A total of 153 community-dwelling people aged 65+ years took part in this international, multicentre, randomized controlled trial. Intervention group participants conducted the exercise program for 16 weeks, with a recommended duration of 120 min/week for balance exergames and 60 min/week for strength exercises. All intervention and control participants received educational material including advice on a healthy lifestyle and fall prevention. Assessments included physical and cognitive tests, and questionnaires for health, fear of falling, number of falls, quality of life and psychosocial outcomes. Results: The median total exercise duration was 11.7 h (IQR = 22.0) over the 16-week intervention period. There were no adverse events. Physiological fall risk (Physiological Profile Assessment, PPA) reduced significantly more in the intervention group compared to the control group (F-1,(127)=4.54,p = 0.035). There was a significant three-way interaction for fall risk assessed by the PPA between the high-adherence (> 90 min/week; n = 18, 25.4 %), low-adherence (< 90 min/week; n = 53, 74.6 %) and control group (F-2,(125)=3.12, n = 75, p = 0.044). Post hoc analysis revealed a significantly larger effect in favour of the high-adherence group compared to the control group for fall risk (p = 0.031), postural sway (p = 0.046), stepping reaction time (p = 0.041), executive functioning (p = 0.044), and quality of life (p for trend = 0.052). Conclusions: The iStoppFalls exercise program reduced physiological fall risk in the study sample. Additional subgroup analyses revealed that intervention participants with better adherence also improved in postural sway, stepping reaction, and executive function., The iStoppFalls project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no [287361]. The Australian arm was funded by an Australian National Health and Medical Research Council (NHMRC) EU collaboration grant (#1038210). The content of the manuscript does not represent the opinion of the European Community or NHMRC. The funding sources had no influence in any aspects of this study. Yves J. Gschwind was financially supported by a research grant from the Margarete and Walter Lichtenstein Foundation, Basel, Switzerland. Stephen R. Lord was supported by NHMRC as a Senior Principal Research Fellow. Kim Delbaere was supported by a NHMRC as a Career Development Fellow. The other authors were supported by the European Community Grant Agreement 287361. We would like to thank all the technical engineers, software developers and research staff who contributed to the iStoppFalls project as well as the participants who took part in the study

[EN] Background: Falls are very common, especially in adults aged 65 years and older. Within the current international European Commission's Seventh Framework Program (FP7) project 'iStoppFalls' an Information and Communication Technology (ICT) based system has been developed to regularly assess a person's risk of falling in their own home and to deliver an individual and tailored home-based exercise and education program for fall prevention. The primary aims of iStoppFalls are to assess the feasibility and acceptability of the intervention program, and its effectiveness to improve balance, muscle strength and quality of life in older people. Methods/Design: This international, multicenter study is designed as a single-blinded, two-group randomized controlled trial. A total of 160 community-dwelling older people aged 65 years and older will be recruited in Germany (n = 60), Spain (n = 40), and Australia (n = 60) between November 2013 and May 2014. Participants in the intervention group will conduct a 16-week exercise program using the iStoppFalls system through their television set at home. Participants are encouraged to exercise for a total duration of 180 minutes per week. The training program consists of a variety of balance and strength exercises in the form of video games using exergame technology. Educational material about a healthy lifestyle will be provided to each participant. Final reassessments will be conducted after 16 weeks. The assessments include physical and cognitive tests as well as questionnaires assessing health, fear of falling, quality of life and psychosocial determinants. Falls will be followed up for six months by monthly falls calendars. Discussion: We hypothesize that the regular use of this newly developed ICT-based system for fall prevention at home is feasible for older people. By using the iStoppFalls sensor-based exercise program, older people are expected to improve in balance and strength outcomes. In addition, the exercise training may have a positive impact on quality of life by reducing the risk of falls. Taken together with expected cognitive improvements, the individual approach of the iStoppFalls program may provide an effective model for fall prevention in older people who prefer to exercise at home., The authors are members of the iStoppFalls project. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development, and demonstration under grant agreement no [287361]. The Australian arm is funded by an Australian National Health and Medical Research Council (NHMRC) EU collaboration grant (#1038210). The content of the manuscript does not represent the opinion of the European Community or NHMRC. The funding sources have no role in any aspects of this study. Yves J. Gschwind has been financially supported by a research grant from the Margarete and Walter Lichtenstein Foundation, Basel, Switzerland. Stephen R. Lord is supported by NHMRC as a Senior Principal Research Fellow and Kim Delbaere as a NHMRC Career Development Fellow. All other authors are supported by the iStoppFalls project, European Community Grant Agreement 287361. On behalf the iStoppFalls consortium, we would like to thank all the participants who take part in the study.

BackgroundTo date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects.Methodology/principal findings79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%).Conclusions/significanceCOPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD.

Generally, the use of a rollator improves mobility in patients with COPD. Nevertheless, not all patients benefit from its use, and many patients feel embarrassed about using it. Therefore, other walking aids are worthwhile to consider. We compared the direct effects of a "new" ambulation aid (a modern draisine) with the effects of a rollator on 6-min walk distance (6MWD) in patients with COPD.Twenty-one patients with COPD performed two 6-min walk tests (6MWTs) during prerehabilitation assessment (best 6MWD: 369 ± 88 m). Additionally, two extra 6MWTs were performed on two consecutive days in random order: one time with a rollator and one time with a modern draisine. Walking pattern (n = 21) was determined using an accelerometer, and metabolic requirements (n = 10) were assessed using a mobile oxycon.Walking with the modern draisine resulted in a higher 6MWD compared with walking with the rollator (466 ± 189 m vs 383 ± 85 m). Moreover, patients had fewer strides (245 ± 61 vs 300 ± 49) and a greater stride length (1.89 ± 0.73 m vs 1.27 ± 0.14 m) using the modern draisine compared with the rollator (all P ≤ .001). Oxygen uptake, ventilation, heart rate, oxygen saturation, and Borg symptom scores were comparable between both walking aids. Ten percent of the patients felt embarrassed using the modern draisine compared with 19% for the rollator, and a significantly smaller proportion of patients would use the modern draisine in daily life.The mean difference in 6MWD between a modern draisine and a rollator seems clinically relevant, with the same metabolic requirements and symptom Borg scores. Therefore, this "new" ambulation aid could be a good alternative to the rollator to improve functional exercise performance in patients with COPD.The Netherlands National Trial Registry; No.: NTR1542; URL: www.trialregister.nl.

Annegarn J, Spruit MA, Uszko-Lencer NHMK, Vanbelle S, Savelberg HHCM, Schols AMWJ, Wouters EFM, Meijer K. Objective physical activity assessment in patients with chronic organ failure: a validation study of a new single-unit activity monitor. Objective To validate a new activity monitor (CAM) in patients with chronic organ failure during 1 hour of unconstrained activity assessment. Design A validation study in which participants wore a CAM (placed on the thigh) for 1 hour while they were videotaped. Participants were instructed to continue their normal daily routine at the rehabilitation center. Setting CIRO+, A Centre of Expertise for Chronic Organ Failure. Participants Chronic organ failure patients (N=10) with a large range of functional exercise capacity. Interventions Not applicable. Main Outcome Measure Agreement in time spent on activities and postures according to video and CAM. Results Cohen kappa coefficients for transient events resulted in an almost perfect agreement (0.85±0.08) between the CAM and video. Conclusions The CAM is a promising single-sensor unobtrusive tool for providing accurate data on the type and duration of daily activities in the home environment of patients with chronic organ failure.

From the authors: H.S. Kulkarni and coworkers argue that a mean increase in 6-min walk distance (6MWD) of 27 m during a second 6-min walk test (6MWT) in 1,514 patients with chronic obstructive pulmonary disease (COPD) still does not provide enough evidence to consider performing two 6MWTs [1]. Even though we very much appreciate this correspondence, we disagree with the arguments and conclusions of H.S. Kulkarni and coworkers. H.S. Kulkarni and coworkers state that we implied that only the result of the second 6MWT should …

Background \ud Falls in older people represent a major age-related health challenge facing our society. Novel methods for delivery of falls prevention programs are required to increase effectiveness and adherence to these programs while containing costs. The primary aim of the Information and Communications Technology-based System to Predict and Prevent Falls (iStoppFalls) project was to develop innovative home-based technologies for continuous monitoring and exercise-based prevention of falls in community-dwelling older people. The aim of this paper is to describe the components of the iStoppFalls system. \ud Methods \ud The system comprised of 1) a TV, 2) a PC, 3) the Microsoft Kinect, 4) a wearable sensor and 5) an assessment and training software as the main components. \ud Results \ud The iStoppFalls system implements existing technologies to deliver a tailored home-based exercise and education program aimed at reducing fall risk in older people. A risk assessment tool was designed to identify fall risk factors. The content and progression rules of the iStoppFalls exergames were developed from evidence-based fall prevention interventions targeting muscle strength and balance in older people. \ud Conclusions \ud The iStoppFalls fall prevention program, used in conjunction with the multifactorial fall risk assessment tool, aims to provide a comprehensive and individualised, yet novel fall risk assessment and prevention program that is feasible for widespread use to prevent falls and fall-related injuries. This work provides a new approach to engage older people in home-based exercise programs to complement or provide a potentially motivational alternative to traditional exercise to reduce the risk of falling.