Application of Dynamic Mode Decomposition to Characterize Temporal Evolution of Plantar Pressures from Walkway Sensor Data in Women with Cancer.

Pressure sensor-impregnated walkways transform a person's footfalls into spatiotemporal signals that may be sufficiently complex to inform emerging artificial intelligence (AI) applications in healthcare. Key consistencies within these plantar signals show potential to uniquely identify a person, and to distinguish groups with and without neuromotor pathology. Evidence shows that plantar pressure distributions are altered in aging and diabetic peripheral neuropathy, but less is known about pressure dynamics in chemotherapy-induced peripheral neuropathy (CIPN), a condition leading to falls in cancer survivors. Studying pressure dynamics longitudinally as people develop CIPN will require a composite model that can accurately characterize a survivor's gait consistencies before chemotherapy, even in the presence of normal step-to-step variation. In this paper, we present a state-of-the-art data-driven learning technique to identify consistencies in an individual's plantar pressure dynamics. We apply this technique to a database of steps taken by each of 16 women before they begin a new course of neurotoxic chemotherapy for breast or gynecologic cancer. After extracting gait features by decomposing spatiotemporal plantar pressure data into low-rank dynamic modes characterized by three features: frequency, a decay rate, and an initial condition, we employ a machine-learning model to identify consistencies in each survivor's walking pattern using the centroids for each feature. In this sample, our approach is at least 86% accurate for identifying the correct individual using their pressure dynamics, whether using the right or left foot, or data from trials walked at usual or fast speeds. In future work, we suggest that persistent deviation from a survivor's pre-chemotherapy step consistencies could be used to automate the identification of peripheral neuropathy and other chemotherapy side effects that impact mobility.

Development and Earliest Validation of a Portable Device for Quantification of Hallux Extension Strength (QuHalEx).

Hallux strength is associated with sports performance and balance across the lifespan, and independently predicts falls in older adults. In rehabilitation, Medical Research Council (MRC) Manual Muscle Testing (MMT) is the clinical standard for hallux strength assessment, but subtle weakness and longitudinal changes in strength may go undetected. To address the need for research-grade yet clinically feasible options, we designed a new load cell device and testing protocol to Quantify Hallux Extension strength (QuHalEx). We aim to describe the device, protocol and initial validation. In benchtop testing, we used eight precision weights to apply known loads from 9.81 to 78.5 N. In healthy adults, we performed three maximal isometric tests for hallux extension and flexion on the right and left sides. We calculated the Intraclass Correlation Coefficient (ICC) with 95% confidence interval and descriptively compared our isometric force-time output to published parameters. QuHalEx benchtop absolute error ranged from 0.02 to 0.41 (mean 0.14) N. Benchtop and human intrasession output was repeatable (ICC 0.90-1.00, p < 0.001). Hallux strength in our sample (n = 38, age 33.5 ± 9.6 years, 53% female, 55% white) ranged from 23.1 to 82.0 N peak extension force and 32.0 to 142.4 N peak flexion, and differences of ~10 N (15%) between toes of the same MRC grade (5) suggest that QuHalEx is able to detect subtle weakness and interlimb asymmetries that are missed by MMT. Our results support ongoing QuHalEx validation and device refinement with a longer-term goal of widespread clinical and research application.

What is the relation between fear of falling and physical activity in older adults?

OBJECTIVE: To describe the association between fear of falling (FOF) and total daily activity in older adults. DESIGN: Cross-sectional observational study. SETTING: Ambulatory clinical research training center. PARTICIPANTS: Community-dwelling older adults aged ≥64 years (N=78), who were independent in ambulation with or without an assistive device. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: FOF was defined by self-reported fear ratings using the Survey of Activities and Fear of Falling in the Elderly and self-reported fear status determined by response to the following question: Are you afraid of falling? Physical function was assessed using the Late Life Function and Disability Instrument. Physical activity was recorded using an accelerometer worn on the waist for 7 consecutive days, and mean daily counts of activity per minute were averaged over the 7-day period. RESULTS: Fear ratings were related to total daily activity (r=-.26, P=.02). The relation was not as strong as the relation of function and physical activity (r=.45, P<.001). When stratified by exercise status or functional status, fear was no longer related to total daily activity. Physical function explained 19% of the variance in physical activity, whereas the addition of fear status did not add to the explained variance in physical activity. CONCLUSIONS: FOF is related to total daily physical activity; however, FOF was not independently associated with physical activity when accounting for physical function. Some FOF may be reported as a limitation in function.

Cancer Rehabilitation Publications (2008-2018) With a Focus on Physical Function: A Scoping Review.

BACKGROUND: Cancer rehabilitation research has accelerated over the last decade. However, closer examination of the published literature reveals that the majority of this work has focused on psychological interventions and cognitive and behavioral therapies. Recent initiatives have aggregated expert consensus around research priorities, highlighting a dearth in research regarding measurement of and interventions for physical function. Increasingly loud calls for the need to address the myriad of physical functional impairments that develop in people living with and beyond cancer have been published in the literature. A detailed survey of the landscape of published research has not been reported to our knowledge. PURPOSE: This scoping review systematically identified literature published between 2008 and 2018 related to the screening, assessment, and interventions associated with physical function in people living with and beyond cancer. DATA SOURCES: PubMed and CINAHL were searched up to September 2018. STUDY SELECTION: Study selection included articles of all levels of evidence on any disease stage and population. A total of 11,483 articles were screened for eligibility, 2507 full-text articles were reviewed, and 1055 articles were selected for final inclusion and extraction. DATA EXTRACTION: Seven reviewers recorded type of cancer, disease stage, age of participants, phase of treatment, time since diagnosis, application to physical function, study design, impairments related to physical function, and measurement instruments used. DATA SYNTHESIS: Approximately one-third of the articles included patients with various cancer diagnoses (30.3%), whereas the rest focused on a single cancer, most commonly breast (24.8%). Most articles (77%) measured physical function following the completion of active cancer treatment with 64% representing the assessment domain. The most commonly used measures of physical function were the Medical Outcomes Study 36-Item Health Survey Questionnaire (29%) and the European Organization for Research and Treatment of cancer Quality of Life Questionnaire-Cancer 30 (21.5%). LIMITATIONS: Studies not written in English, study protocols, conference abstracts, and unpublished data were excluded. CONCLUSIONS: This review elucidated significant inconsistencies in the literature regarding language used to define physical function, measurement tools used to characterize function, and the use of those tools across the cancer treatment and survivorship trajectory. The findings suggested that physical function in cancer research is predominantly measured using general health-related quality-of-life tools rather than more precise functional assessment tools. Interdisciplinary and clinician-researcher collaborative efforts should be directed toward a unified definition and assessment of physical function.

Comparative Clinical Effectiveness of Nonsurgical Treatment Methods in Patients With Lumbar Spinal Stenosis: A Randomized Clinical Trial.

Importance: Lumbar spinal stenosis (LSS) is the most common reason for spine surgery in older US adults. There is an evidence gap about nonsurgical LSS treatment options. Objective: To explore the comparative clinical effectiveness of 3 nonsurgical interventions for patients with LSS. Design, Setting, and Participants: Three-arm randomized clinical trial of 3 years' duration (November 2013 to June 2016). Analysis began in August 2016. All interventions were delivered during 6 weeks with follow-up at 2 months and 6 months at an outpatient research clinic. Patients older than 60 years with LSS were recruited from the general public. Eligibility required anatomical evidence of central canal and/or lateral recess stenosis (magnetic resonance imaging/computed tomography) and clinical symptoms associated with LSS (neurogenic claudication; less symptoms with flexion). Analysis was intention to treat. Interventions: Medical care, group exercise, and manual therapy/individualized exercise. Medical care consisted of medications and/or epidural injections provided by a physiatrist. Group exercise classes were supervised by fitness instructors in senior community centers. Manual therapy/individualized exercise consisted of spinal mobilization, stretches, and strength training provided by chiropractors and physical therapists. Main Outcomes and Measures: Primary outcomes were between-group differences at 2 months in self-reported symptoms and physical function measured by the Swiss Spinal Stenosis questionnaire (score range, 12-55) and a measure of walking capacity using the self-paced walking test (meters walked for 0 to 30 minutes). Results: A total of 259 participants (mean [SD] age, 72.4 [7.8] years; 137 women [52.9%]) were allocated to medical care (88 [34.0%]), group exercise (84 [32.4%]), or manual therapy/individualized exercise (87 [33.6%]). Adjusted between-group analyses at 2 months showed manual therapy/individualized exercise had greater improvement of symptoms and physical function compared with medical care (-2.0; 95% CI, -3.6 to -0.4) or group exercise (-2.4; 95% CI, -4.1 to -0.8). Manual therapy/individualized exercise had a greater proportion of responders (≥30% improvement) in symptoms and physical function (20%) and walking capacity (65.3%) at 2 months compared with medical care (7.6% and 48.7%, respectively) or group exercise (3.0% and 46.2%, respectively). At 6 months, there were no between-group differences in mean outcome scores or responder rates. Conclusions and Relevance: A combination of manual therapy/individualized exercise provides greater short-term improvement in symptoms and physical function and walking capacity than medical care or group exercises, although all 3 interventions were associated with improvements in long-term walking capacity. Trial Registration: ClinicalTrials.gov Identifier: NCT01943435.

Comparison of non-surgical treatment methods for patients with lumbar spinal stenosis: protocol for a randomized controlled trial.

BACKGROUND: Lumbar spinal stenosis is the most common reason for spinal surgery in older adults. Previous studies have shown that surgery is effective for severe cases of stenosis, but many patients with mild to moderate symptoms are not surgical candidates. These patients and their providers are seeking effective non-surgical treatment methods to manage their symptoms; yet there is a paucity of comparative effectiveness research in this area. This knowledge gap has hindered the development of clinical practice guidelines for non-surgical treatment approaches for lumbar spinal stenosis. METHODS/DESIGN: This study is a prospective randomized controlled clinical trial that will be conducted from November 2013 through October 2016. The sample will consist of 180 older adults (>60 years) who have both an anatomic diagnosis of stenosis confirmed by diagnostic imaging, and signs/symptoms consistent with a clinical diagnosis of lumbar spinal stenosis confirmed by clinical examination. Eligible subjects will be randomized into one of three pragmatic treatment groups: 1) usual medical care; 2) individualized manual therapy and rehabilitative exercise; or 3) community-based group exercise. All subjects will be treated for a 6-week course of care. The primary subjective outcome is the Swiss Spinal Stenosis Questionnaire, a self-reported measure of pain/function. The primary objective outcome is the Self-Paced Walking Test, a measure of walking capacity. The secondary objective outcome will be a measurement of physical activity during activities of daily living, using the SenseWear Armband, a portable device to be worn on the upper arm for one week. The primary analysis will use linear mixed models to compare the main effects of each treatment group on the changes in each outcome measure. Secondary analyses will include a responder analysis by group and an exploratory analysis of potential baseline predictors of treatment outcome. DISCUSSION: Our study should provide evidence that helps to inform patients and providers about the clinical benefits of three non-surgical approaches to the management of lumbar spinal stenosis symptoms. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01943435.

The modified Gait Efficacy Scale: establishing the psychometric properties in older adults.

BACKGROUND: Perceived ability or confidence plays an important role in determining function and behavior. The modified Gait Efficacy Scale (mGES) is a 10-item self-report measure used to assess walking confidence under challenging everyday circumstances. OBJECTIVE: The purpose of this study was to determine the reliability, internal consistency, and validity of the mGES as a measure of gait in older adults. DESIGN: This was a cross-sectional study. METHODS: Participants were 102 community-dwelling older adults (mean [±SD] age=78.6±6.1 years) who were independent in ambulation with or without an assistive device. Participants were assessed using the mGES and measures of confidence and fear, measures of function and disability, and performance-based measures of mobility. In a subsample (n=26), the mGES was administered twice within a 1-month period to establish test-retest reliability through the intraclass correlation coefficient (ICC [2,1]). The standard error of measure (SEM) was determined from the ICC and standard deviation. The Cronbach α value was calculated to determine internal consistency. To establish the validity of the mGES, the Spearman rank order correlation coefficient was used to examine the association with measures of confidence, fear, gait, and physical function and disability. RESULTS: The mGES demonstrated test-retest reliability within the 1-month period (ICC=.93, 95% confidence interval=.85, .97). The SEM of the mGES was 5.23. The mGES was internally consistent across the 10 items (Cronbach α=.94). The mGES was related to measures of confidence and fear (r=.54-.88), function and disability (Late-Life Function and Disability Instrument, r=.32-.88), and performance-based mobility (r=.38-.64). LIMITATIONS: This study examined only community-dwelling older adults. The results, therefore, should not be generalized to other patient populations. CONCLUSION: The mGES is a reliable and valid measure of confidence in walking among community-dwelling older adults.

Interpreting the need for initial support to perform tandem stance tests of balance.

BACKGROUND: Geriatric rehabilitation reimbursement increasingly requires documented deficits on standardized measures. Tandem stance performance can characterize balance, but protocols are not standardized. Objective The purpose of this study was to explore the impact of: (1) initial support to stabilize in position and (2) maximum hold time on tandem stance tests of balance in older adults. Design A cross-sectional secondary analysis of observational cohort data was conducted. METHODS: One hundred seventeen community-dwelling older adults (71% female, 12% black) were assigned to 1 of 3 groups based on the need for initial support to perform tandem stance: (1) unable even with support, (2) able only with support, and (3) able without support. The able without support group was further stratified on hold time in seconds: (1) <10 (low), (2) 10 to 29, (medium), and (3) 30 (high). Groups were compared on primary outcomes (gait speed, Timed "Up & Go" Test performance, and balance confidence) using analysis of variance. RESULTS: Twelve participants were unable to perform tandem stance, 14 performed tandem stance only with support, and 91 performed tandem stance without support. Compared with the able without support group, the able with support group had statistically or clinically worse performance and balance confidence. No significant differences were found between the able with support group and the unable even with support group on these same measures. Extending the hold time to 30 seconds in a protocol without initial support eliminated ceiling effects for 16% of the study sample. Limitations Small comparison groups, use of a secondary analysis, and lack of generalizability of results were limitations of the study. CONCLUSIONS: Requiring initial support to stabilize in tandem stance appears to reflect meaningful deficits in balance-related mobility measures, so failing to consider support may inflate balance estimates and confound hold time comparisons. Additionally, 10-second maximum hold times limit discrimination of balance in adults with a higher level of function. For community-dwelling older adults, we recommend timing for at least 30 seconds and documenting initial support for consideration when interpreting performance.

Association of body mass index with self-report and performance-based measures of balance and mobility.

BACKGROUND: The incidence of obesity is increasing in older adults, with associated worsening in the burden of disability. Little is known about the impact of body mass index (BMI) on self-report and performance-based balance and mobility measures in older adults. OBJECTIVE: The purposes of this study were (1) to examine the association of BMI with measures of balance and mobility and (2) to explore potential explanatory factors. DESIGN: This was a cross-sectional, observational study. METHODS: Older adults (mean age=77.6 years) who participated in an ongoing observational study (N=120) were classified as normal weight (BMI=18.5-24.9 kg/m(2)), overweight (BMI=25.0-29.9 kg/m(2)), moderately obese (BMI=30.0-34.9 kg/m(2)), or severely obese (BMI ≥ 35 kg/m(2)). Body mass index data were missing for one individual; thus, data for 119 participants were included in the analysis. Mobility and balance were assessed using self-report and performance-based measures and were compared among weight groups using analysis of variance and chi-square analysis for categorical data. Multiple linear regression analysis was used to examine the association among BMI, mobility, and balance after controlling for potential confounding variables. RESULTS: Compared with participants who were of normal weight or overweight, those with moderate or severe obesity were less likely to report their mobility as very good or excellent (52%, 55%, 39%, and 6%, respectively); however, there was no difference in self-report of balance among weight groups. Participants with severe obesity (n=17) had the lowest levels of mobility on the performance-based measures, followed by those who were moderately obese (n=31), overweight (n=42), and of normal weight (n=29). There were no differences on performance-based balance measures among weight groups. After controlling for age, sex, minority status, physical activity level, education level, and comorbid conditions, BMI still significantly contributed to mobility (ß=-.02, adjusted R(2)=.41). CONCLUSIONS: Although older adults with severe obesity were most impaired, those with less severe obesity also demonstrated significant decrements in mobility.

Challenging gait conditions predict 1-year decline in gait speed in older adults with apparently normal gait.

BACKGROUND: Mobility often is tested under a low challenge condition (ie, over a straight, uncluttered path), which often fails to identify early mobility difficulty. Tests of walking during challenging conditions may uncover mobility difficulty that is not identified with usual gait testing. OBJECTIVE: The purpose of this study was to determine whether gait during challenging conditions predicts decline in gait speed over 1 year in older people with apparently normal gait (ie, gait speed of ≥1.0 m/s). DESIGN: This was a prospective cohort study. METHODS: /b> Seventy-one older adults (mean age=75.9 years) with a usual gait speed of ≥1.0 m/s participated. Gait was tested at baseline under 4 challenging conditions: (1) narrow walk (15 cm wide), (2) stepping over obstacles (15.24 cm [6 in] and 30.48 cm [12 in]), (3) simple walking while talking (WWT), and (4) complex WWT. Usual gait speed was recorded over a 4-m course at baseline and 1 year later. A 1-year change in gait speed was calculated, and participants were classified as declined (decreased ≥0.10 m/s, n=18), stable (changed <0.10 m/s, n=43), or improved (increased ≥0.10 m/s, n=10). Analysis of variance was used to compare challenging condition cost (usual--challenging condition gait speed difference) among the 3 groups. RESULTS: Participants who declined in the ensuing year had a greater narrow walk and obstacle walk cost than those who were stable or who improved in gait speed (narrow walk cost=0.43 versus 0.33 versus 0.22 m/s and obstacle walk cost=0.35 versus 0.26 versus 0.13 m/s). Simple and complex WWT cost did not differ among the groups. LIMITATIONS: The participants who declined in gait speed over time walked the fastest, and those who improved walked the slowest at baseline; thus, the potential contribution of regression to the mean to the findings should not be overlooked. CONCLUSIONS: In older adults with apparently normal gait, the assessment of gait during challenging conditions appears to uncover mobility difficulty that is not identified by usual gait testing.

Persistent mobility disability after neurotoxic chemotherapy.

BACKGROUND AND PURPOSE: The impact of cancer and its treatments on balance and functional mobility in older adults remains unknown but is increasingly important, given the evolution of cancer treatments. Subacute and more persistent side effects such as chemotherapy-induced peripheral neuropathy are on the rise, and the effects on mobility and balance, as well as the prognosis for resolution of any functional deficits, must be established before interventions can be trialed. The purpose of this case report is to describe the severity and long-term persistence of mobility decline in an older adult who received neurotoxic chemotherapy. To our knowledge, this is the first case report to describe an older adult with chemotherapy-induced peripheral neuropathy using results of standardized balance and mobility tests and to focus on prognosis by repeating these measures more than 2 years after chemotherapy. CASE DESCRIPTION: An 81-year-old woman received a neurotoxic agent (paclitaxel) after curative mastectomy for breast cancer. Baseline testing prior to taxane therapy revealed a socially active woman with no reported functional deficits or neuropathic symptoms, 1.2-m/s gait speed, and performance at the ceiling on balance and gait portions of a standardized mobility measure. OUTCOMES: After 3 cycles, paclitaxel therapy was stopped by the oncologist because of neurotoxicity. Declines as large as 50% were seen in performance-based measures at 12 weeks and persisted at 2.5 years, and the patient reported recurrent falls, cane use, and mobility-related disability. DISCUSSION: This case highlights the extent to which function can decline in an older individual receiving neurotoxic chemotherapy, the potential for these deficits to persist years after treatment is stopped, and the need for physical therapy intervention and further research in this population.