Detection of Real-World Trips in At-Fall Risk Community Dwelling Older Adults Using Wearable Sensors.

Background: Near-falls such as a trip, slip, stumble, or misstep involve a loss of balance (LOB) that does not result in a fall, occur more frequently than actual falls, and are associated with an increased fall risk. To date, studies have largely involved detection of simulated laboratory LOBs using wearable devices in young adults. Data on the detection of and kinematics of naturally occurring LOBs in people at high risk of falling are lacking. This may provide a new way to identify older adults at high risk for falls. We aimed to explore key body kinematics underlying real-world trips in at-fall risk community dwelling older adults wearing inertial measurement units (IMU). Methods: Five community-dwelling older adults with a history of falls who reported trips during the study period participated. They wore a voice recorder and 4 IMUs mounted on feet, lower back and wrist for two consecutive weeks to provide a record of the context and timing of LOB events. Sensor data prior to time-stamped voice recording of a trip were processed in order to visually identify unusual foot trajectories and lower back and arm orientations. Then, data of feet, lower back and wrist position and orientation were combined to create a three-dimensional animation representing the estimated body motion during the noted time segments in order to corroborate the occurrence of a trip. Events reported as a trip by the participant and identified as a trip by a researcher, blinded to voice recordings description, were included in the final analysis. Results: A total of 18 trips obtained from five participants were analyzed. Twelve trips occurred at home, three outside and for three the location was not reported. Trips were identified in the sensor data by observing (1) additional peaks to the typical foot velocity signal during swing phase; (2) increased velocity of the contralateral foot and (3) sharp changes in lower back pitch angles. Conclusions: Our approach demonstrates the feasibility of identifying and studying the mechanisms and context underlying trip-related LOBs in at-fall risk older adults during real world activities.

Functional Exercise Improves Mobility Performance in Older Adults With Type 2 Diabetes: A Randomized Controlled Trial.

Background: Diabetes-related disability occurs in approximately two-thirds of older adults with diabetes and is associated with loss of independence, increased health care resource utilization, and sedentary lifestyle. The objective of this randomized controlled trial was to determine the effect of a center-based functional circuit exercise training intervention followed by a 10-week customized home-based program in improving mobility function in sedentary older adults with diabetes. Methods: Participants (n = 111; mean age 70.5 [7.1] y; mean body mass index 32.7 [5.9] kg/m2) were randomized to either a moderate-intensity functional circuit training (FCT) plus 10-week home program to optimize physical activity (FCT-PA) primary intervention or one of 2 comparison groups (FCT plus health education [FCT-HE] or flexibility and toning plus health education [FT-HE]). Results: Compared with FT-HE, FCT-PA improvements in comfortable gait speed of 0.1 m/s (P < .05) and 6-minute walk of 80 ft were consistent with estimates of clinically meaningful change. At 20 weeks, controlling for 10-week outcomes, improvements were found between groups for comfortable gait speed (FCT-PA vs FT-HE and FCT-HE vs FT-HE) and 6-minute walk (FCT-PA vs FCT-HE). Conclusions: Functional exercise training can improve mobility in overweight/obese older adults with diabetes and related comorbidities. Future studies should evaluate intervention sustainability and adaptations for those with more severe mobility impairments.

Reconstruction of body motion during self-reported losses of balance in community-dwelling older adults.

Older adults experience slips, trips, stumbles, and other losses of balance (LOBs). LOBs are more common than falls and are closely linked to falls and fall-injuries. Data about real-world LOBs is limited, particularly information quantifying the prevalence, frequency, and intrinsic and extrinsic circumstances in which they occur. This paper describes a new method to identify and analyze LOBs through long-term recording of community-dwelling older adults. The approach uses wearable inertial measurement units (IMUs) on the feet, trunk and one wrist, together with a voice recorder for immediate, time-stamped self-reporting of the type, context and description of LOBs. Following identification of an LOB in the voice recording, concurrent IMU data is used to estimate foot paths and body motions, and to create body animations to analyze the event. In this pilot study, three older adults performed a long-term monitoring study, with four weeks recording LOBs by voice and two concurrent weeks wearing IMUs. This report presents a series of LOB cases to illustrate the proposed method, and how it can contribute to interpretation of the causes and contexts of the LOBs. The context and timing information from the voice records was critical to the process of finding and analyzing LOB events within the voluminous sensor data record, and included much greater detail, specificity, and nuance than past diary or smartphone reporting.

What features of the built environment matter most for mobility? Using wearable sensors to capture real-time outdoor environment demand on gait performance.

BACKGROUND: A growing body of research has demonstrated relationships between built environment characteristics and outdoor mobility. However, most of this work has relied on composite scores of the built environment. RESEARCH QUESTION: Which properties of the outdoor built environment are associated with the greatest change in gait metrics in a real-world setting? METHODS: 25 community-dwelling adults from Southeast Michigan were equipped with mobile inertial measurement units and walked a 1300-meter outdoor course with varying environmental demands. Environmental properties were documented in sections of the course using the Senior Walking Environmental Assessment Tool. Gait speed, left foot cadence, and stride length were used to identify the built environment properties under which mobility was most challenged using linear mixed models. We hypothesized that subjects would adapt to demanding environments by decreasing gait speed, increasing cadence, and shortening stride length. RESULTS: Properties of the built environment were significantly associated with changes in gait speed, left foot cadence, and stride length. Properties that were most important for predicting gait speed included slope, sidewalk condition, and presence of holes. Sidewalk slope, bumps, and the presence of a curb cut were all significant predictors of left foot cadence. Mean stride length of the outdoor course was significantly associated with the section's condition, slope, holes, bumps, width, and the presence of grooves and bumps at a curb. SIGNIFICANCE: Associations between environmental properties and gait parameters were differential across the three mobility outcomes. When examining which properties of the built environment are challenging to navigate it is important to understand the relative influence of specific properties on gait metrics. Knowledge of which built environment properties are barriers for walking behavior is critical for the design of inclusive sidewalks and streets.

Performance-Based Measures Associate With Frailty in Patients With End-Stage Liver Disease.

BACKGROUND: Physical frailty, as measured by the Fried Frailty Index, is increasingly recognized as a critical determinant of outcomes in patients with cirrhosis. However, its utility is limited by the inclusion of self-reported components. We aimed to identify performance-based measures associated with frailty in patients with cirrhosis. METHODS: Patients with cirrhosis, aged 50 years or older, underwent: 6-minute walk test (cardiopulmonary endurance), chair stands in 30 seconds (muscle endurance), isometric knee extension (lower extremity strength), unipedal stance time (static balance), and maximal step length (dynamic balance/coordination). Linear regression associated each physical performance test with frailty. Principal components exploratory factor analysis evaluated the interrelatedness of frailty and the 5 physical performance tests. RESULTS: Of 40 patients with cirrhosis, with a median age of 64 years and Model for End-stage Liver Disease (MELD) MELD of 12.10 (25%) were frail by Fried Frailty Index ≥3. Frail patients with cirrhosis had poorer performance in 6-minute walk test distance (231 vs 338 m), 30-second chair stands (7 vs 10), isometric knee extension (86 vs 122 Newton meters), and maximal step length (22 vs 27 in. (P ≤ 0.02 for each). Each physical performance test was significantly associated with frailty (P < 0.01), even after adjustment for MELD or hepatic encephalopathy. Principal component factor analysis demonstrated substantial, but unique, clustering of each physical performance test to a single factor-frailty. CONCLUSIONS: Frailty in cirrhosis is a multidimensional construct that is distinct from liver dysfunction and incorporates endurance, strength, and balance. Our data provide specific targets for prehabilitation interventions aimed at reducing frailty in patients with cirrhosis in preparation for liver transplantation.

Effects of activity strategy training on pain and physical activity in older adults with knee or hip osteoarthritis: a pilot study.

OBJECTIVE: To examine effects of activity strategy training (AST), a structured rehabilitation program taught by occupational therapists and designed to teach adaptive strategies for symptom control and engagement in physical activity (PA). METHODS: A randomized controlled pilot trial was conducted at 4 sites (3 senior housing facilities and 1 senior center) in southeastern, lower Michigan. Fifty-four older adults with hip or knee osteoarthritis (mean +/- SD age 75.3+/-7.1 years) participated. At each site, older adults were randomly assigned to 1 of 2 programs: exercise plus AST (Ex + AST) or exercise plus health education (Ex + Ed). The programs involved 8 sessions over 4 weeks with 2 followup sessions over a 6-month period, and were conducted concurrently within each site. Pain, total PA and PA intensity (measured objectively by actigraphy and subjectively by the Community Healthy Activities Model Program for Seniors questionnaire), arthritis self-efficacy, and physical function were assessed at baseline and posttest. RESULTS: At posttest, participants who received Ex + AST had significantly higher levels of objective peak PA (P=0.02) compared with participants who received Ex + Ed. Although not statistically significant, participants in Ex + AST tended to have larger pain decreases, increased total objective and subjective PA, and increased physical function. No effects were found for arthritis self-efficacy. CONCLUSION: Although participants were involved in identical exercise programs, participants who received AST tended to have larger increases in PA at posttest compared with participants who received health education. Future studies will be needed to examine larger samples and long-term effects of AST.

Bath transfers in older adult congregate housing residents: assessing the person-environment interaction.

OBJECTIVES: To examine environmental feature utilization (EFU) and the types and prevalence of performance difficulties during a videotaped bath transfer and to determine the personal characteristics associated with total EFU and performance difficulties. DESIGN: Cross-sectional analysis. SETTING: Two congregate housing facilities in southeastern Michigan. PARTICIPANTS: Eighty-nine older adults who reported independence in bathing. MEASUREMENTS: Trained video coders recorded EFU (defined as upper extremity contact with features in the environment) and rated performance difficulties (defined as lack of fluid movement or difficulty negotiating the environment). EFU was measured by determining whether features used were safe (i.e., designed for use as a transfer support) or unsafe and by total EFU (i.e., number of environmental features used during the transfer). Personal characteristics included self-reported medical conditions, bath transfer difficulty, functional mobility, lower extremity strength, range of motion functional impairment, and falls efficacy. RESULTS: For participants with a tub-shower, safe EFU was higher than unsafe EFU (85% vs 19%; P<.001). Participants with shower stalls had the same rate of safe and unsafe EFU (71%). In multiple regression analysis, self-reported bath transfer difficulty was associated with total EFU (P=.01). One-third of the sample had performance difficulties. In multivariate analysis, range of motion functional impairment (odds ratio (OR)=13.49, 95% confidence interval (CI)=1.11-163.53) and lowest quartile in falls efficacy scores (OR=5.81, 95% CI=1.24-27.41) were associated with performance difficulties. CONCLUSION: Unsafe EFU and performance difficulties were common in independently bathing older adults. Self-reported bath transfer difficulty appears to be a good indicator of high total EFU and may be used as a screening question for clinicians. Important strategies to reduce unsafe EFU and to increase falls efficacy include removing shower sliding glass doors and training older adults in safe transfer techniques.

Dynamic balance and stepping versus tai chi training to improve balance and stepping in at-risk older adults.

OBJECTIVES: To compare the effect of two 10-week balance training programs, Combined Balance and Step Training (CBST) versus tai chi (TC), on balance and stepping measures. DESIGN: Prospective intervention trial. SETTING: Local senior centers and congregate housing facilities. PARTICIPANTS: Aged 65 and older with at least mild impairment in the ability to perform unipedal stance and tandem walk. INTERVENTION: Participants were allocated to TC (n = 107, mean age 78) or CBST, an intervention focused on improving dynamic balance and stepping (n = 106, mean age 78). MEASUREMENTS: At baseline and 10 weeks, participants were tested in their static balance (Unipedal Stance and Tandem Stance (TS)), stepping (Maximum Step Length, Rapid Step Test), and Timed Up and Go (TUG). RESULTS: Performance improved more with CBST than TC, ranging from 5% to 10% for the stepping tests (Maximum Step Length and Rapid Step Test) and 9% for TUG. The improvement in TUG represented an improvement of more than 1 second. Greater improvements were also seen in static balance ability (in TS) with CBST than TC. CONCLUSION: Of the two training programs, in which variants of each program have been proven to reduce falls, CBST results in modest improvements in balance, stepping, and functional mobility versus TC over a 10-week period. Future research should include a prospective comparison of fall rates in response to these two balance training programs.