Martha Mohler - Academia.edu (original) (raw)

Papers by Martha Mohler

Archives of Gerontology and Geriatrics, 2021

BACKGROUND Although previous studies showed that frail older adults are more susceptible to devel... more BACKGROUND Although previous studies showed that frail older adults are more susceptible to develop cardiovascular diseases, the underlying effect of frailty on heart rate dynamics is still unclear. The goal of the current study was to measure heart rate changes due to normal speed and rapid walking among non-frail and pre-frail/frail older adults, and to implement heart rate dynamic measures to identify frailty status. METHODS Eighty-eight older adults (≥65 years) were recruited and stratified into frailty groups based on the five-component Fried frailty phenotype. While performing gait tests, heart rate was recorded using a wearable ECG and accelerometer sensors. Groups consisted of 27 non-frail (age = 78.70 ± 7.32) and 61 pre-frail/frail individuals (age = 81.00 ± 8.14). The parameters of interest included baseline heart rate measures (mean heart rate and heart rate variability), and heart rate dynamics due to walking (percentage change in heart rate and required time to reach the maximum heart rate). RESULTS Respectively for normal and rapid walking conditions, pre-frail/frail participants had 46% and 44% less increase in heart rate, and 49% and 27% slower occurrence of heart rate peak, when compared to non-frail older adults (p < 0.04, effect size = 0.71 ± 0.12). Measures of heart rate dynamics showed stronger associations with frailty status compared to baseline resting-state measures (sensitivity = 0.75 and specificity = 0.65 using heart rate dynamics measures, compared to sensitivity = 0.64 and specificity = 0.62 using baseline parameters). CONCLUSIONS These findings suggest that measures of heart rate dynamics in response to daily activities may provide meaningful markers for frailty screening.

Additional file 1: Supplementary Table 1(a-d). Gait performance parameters for 20s, 30s, 40s and ... more Additional file 1: Supplementary Table 1(a-d). Gait performance parameters for 20s, 30s, 40s and 50s continuous walks, one-way ANOVA results, and Cohen's d effect sizes between non-frail(N) and pre-frail(P)/frail(F) groups; Supplementary Table 2. Logistic model performance comparison using gait performance parameters between different duration of continuous walks for 80% specificity.

2016 Computing in Cardiology Conference (CinC), 2016

Uni-channel ECG was recorded using a wearablesensor in 45 female elders aged 65 and above. Partic... more Uni-channel ECG was recorded using a wearablesensor in 45 female elders aged 65 and above. Participants were categorized as non-fallers (n=22) and fallers (n=23) based on historical report of falling in the last 12 month. For data analysis, PVC episodes were extracted using an automatic code developed in Matlab, and checked manually by an expert to ensure accuracy. Number of PVC episodes per hour was extracted as the parameter of interest in this study and compared between fallers and non-fallers using analysis of variance (ANOVA) test. Number of PVC episodes per hour was not significantly different (p>0.05) between non-fallers (41.65±74.22) and fallers (43.62±59.48). In this study, the association of PVC frequency with fall risk and fear of fall was also studied; Number of PVC episodes were higher in high fall risk compared to low fall risk, and in high concern of fall compared to low concern of fall (p>0.05).

PRISMA checklist. (DOCX 22Â kb)

Heart failure (HF) is a common clinical syndrome in older adults, accounting for over 1 million a... more Heart failure (HF) is a common clinical syndrome in older adults, accounting for over 1 million annual hospitalizations, most of which are considered preventable. It also has the highest 30-day hospital readmission rate of any medical condition. Given the growing aging population, increasing lifespan, and longer survival with cardiac disorders, systematic and cost-effective approaches to outpatient HF management must be implemented to reduce readmissions. This edition of Elder Care will review some of those approaches. Daily Monitoring and Targeted Intervention Education should be provided about daily monitoring for the signs/symptoms of worsening HF. Patients/caregivers should be taught about early signs and symptoms of HF exacerbation that often occur in the days and weeks prior to re-hospitalization (Table 1). Interventions can then be made to stabilize the patient to reduce the risk of rehospitalization.

2016 Computing in Cardiology Conference (CinC), 2016

An increased prevalence of ventricular ectopy (Premature Ventricular Contraction, PVC) is associa... more An increased prevalence of ventricular ectopy (Premature Ventricular Contraction, PVC) is associated with increased incidence of congestive heart failure and increased mortality. Increase in incidence of ventricular ectopy with age has been demonstrated in previous studies, but to the best of our knowledge, its association with frailty, a geriatric syndrome that is associated with adverse health outcomes, has not been studied. The aim of this study was to assess the prevalence of ventricular ectopy in older adults across different frailty levels. A uni-channel ECG in 45 older adults aged 65 and above were measured using a wearable ECG recorder. Participants were classified as non-frail (n=22), pre-frail (n=17), and frail (n=6) using the Fried frailty phenotype. PVCs were identified automatically, and subsequently checked manually by an expert to ensure accuracy. Number of PVC beats per hour was considered for ECG assessment and analysis of variance (ANOVA) test was used to evaluate ...

Journal of the American Geriatrics Society, 2016

Human Movement Science, 2021

Studying the dynamics of nonlinear systems can provide additional information about the variabili... more Studying the dynamics of nonlinear systems can provide additional information about the variability structure of the system. Within the current study, we examined the application of regularity and local stability measures to capture motor function alterations due to dual-tasking using a previously validated upper-extremity function (UEF). We targeted young (ages 18 and 30 years) and older adults (65 years or older) with normal cognition based on clinical screening. UEF involved repetitive elbow flexion without counting (ST) and while counting backward by one (DT1) or three (DT3). We measured the regularity (measured by sample entropy (SE)), local stability (measured by the largest Lyapunov exponent (LyE)), as well as conventional peak-dependent variability measures (coefficient of variation of kinematics parameters) to capture motor dynamic alterations due to dual-tasking. Within both groups, only SE showed significant differences between all pairs of UEF condition comparisons, even ST vs DT1 (p = 0.007, effect size = 0.507), for which no peak-dependent parameter showed significant difference. Among all measures, the only parameter that showed a significant difference between young and older adults was LyE (p < 0.001, effect size = 0.453). Current findings highlight the potential of nonlinear analysis to detect aging-related alterations among cognitively healthy participants.

Aging Clinical and Experimental Research, 2020

Background While sensor-based daily physical activity (DPA) gait assessment has been demonstrated... more Background While sensor-based daily physical activity (DPA) gait assessment has been demonstrated to be an effective measure of physical frailty and fall-risk, the repeatability of DPA gait parameters between different days of measurement is not clear. Aims To evaluate test-retest reliability (repeatability) of DPA gait performance parameters, representing the quality of walking, and quantitative gait measures (e.g. number of steps) between two separate days of assessment among older adults. Methods DPA was acquired for 48-h from older adults (age ≥ 65 years) using a tri-axial accelerometer. Continuous walking bouts (≥ 60 s) were identified from acceleration data and used to extract gait performance parameters, including time-and frequency-domain gait parameters, representing walking speed, variability, and irregularity. To assess repeatability, intraclass correlation coefficient (ICC) was calculated using two-way mixed effects F-test models for day-1 vs. day-2 as the independent random effect. Repeatability tests were performed for all participants and also within frailty groups (non-frail and pre-frail/ frail identified using Fried phenotype). Results Data was analyzed from 63 older adults (29 non-frail and 34 pre-frail/frail). Most of the time-and frequency-domain gait performance parameters showed good to excellent repeatability (ICC ≥ 0.70), while quantitative parameters, including number of steps and walking duration showed poor repeatability (ICC < 0.30). Among majority of the gait performance parameters, we observed higher repeatability among the pre-frail/frail group (ICC > 0.78) compared to non-frail individuals (0.39 < ICC < 0.55). Conclusion Gait performance parameters, showed higher repeatability compared to quantitative measures. Higher repeatability among pre-frail/frail individuals may be attributed to a reduced functional capacity for performing more intense and variable physical tasks. Trial registration The clinical trial was retrospectively registered on June 18th, 2013 with ClinicalTrials.gov, identifier NCT01880229.

Alzheimer's & Dementia, 2018

Alzheimer's & Dementia, 2019

Alzheimer's & Dementia, 2019

Journal of Surgical Research, 2019

Background: Available methods for determining outcomes in vascular surgery patients are often sub... more Background: Available methods for determining outcomes in vascular surgery patients are often subjective or not applicable in nonambulatory patients. The purpose of the present study was to assess the association between vascular surgery outcomes and a previously validated upper-extremity function (UEF) method, which incorporates wearable motion sensors for the physical frailty assessment. Materials and methods: Patients (!50 y old) undergoing vascular surgery were recruited. Participants performed the 20-s UEF test, which involved rapid elbow flexion. This technology quantifies physical frailty features including slowness, weakness, exhaustion, and flexibility, which allows grouping individuals into nonfrail, prefrail, and frail categories. Surgical outcomes included length of hospital stay, discharged disposition, and 30d mortality, complications, readmission, and reintervention(s). Associations between outcomes and frailty were assessed using nominal logistic regression models, adjusted for age, gender, body mass index, and wound classification. Results: Thirty-seven participants were recruited: eight nonfrail (age ¼ 62.0 AE 10.6); 22 prefrail (age ¼ 65.6 AE 11.6); and seven frail (age ¼ 68.0 AE 8.0). Significant associations were observed between frailty and length of hospital stay (three times longer among frail participants, P ¼ 0.03), mortality after surgery (two incidents among frail participants, P < 0.01), and adverse discharge disposition (all nonfrail patients were discharged home, whereas only 43% of frail patients discharged home, P ¼ 0.01). Conclusions: This is the first study to validate the utility of UEF among patients undergoing any vascular surgery. Findings suggest that UEF may provide an objective and simple approach for assessing frailty to predict adverse events after vascular surgery, especially for nonambulatory patients.

Background Frailty is an increasingly recognized geriatric syndrome resulting in decline in reser... more Background Frailty is an increasingly recognized geriatric syndrome resulting in decline in reserve across multiple physiological systems. Impaired physical function is a prime indicator of frailty.Objective The goal of this study was to develop an algorithm that discriminates between frailty groups (non-frail, pre-frail, and frail) based on gait performance parameters derived from unsupervised daily physical activity (DPA).Methods DPA was acquired for 48 hours from older adults (≥65 years) using a tri-axial accelerometer motion-sensor. Purposeful continuous bouts of walking (≥60s) without pauses were identified from acceleration data. These were then used to extract qualitative measures (gait variability, gait asymmetry, and gait irregularity) and quantitative measures (total continuous walking duration and maximum number of continuous steps) to characterize gait performance. Association between frailty and gait performance parameters was assessed using multinomial logistic models ...

Gerontology & Geriatrics Education, 2018

As the U.S. population ages and lives longer, we need to assure that future providers are prepare... more As the U.S. population ages and lives longer, we need to assure that future providers are prepared to work in highly functioning interprofessional teams to deliver person-centered care for older adults with complex chronic conditions. Assisted living facilities are ideal venues in which to train interprofessional health sciences students in providing such care. After monthly clinics involving interprofessional students (from the colleges of medicine, nursing, pharmacy, public health, and school of social work) providing team-based care to older adults, students' post-clinic evaluations indicated perceived improvements in knowledge, attitudes, and perceptions about aging and care of older adults. In addition, participating older adults reported improved self-worth and enjoyment. The curriculum, evaluation outcomes, and lessons learned are described to support program replication.

Scientific Reports, 2019

The purpose of the current study was to develop an objective tool based on dual-task performance ... more The purpose of the current study was to develop an objective tool based on dual-task performance for screening early-stage Alzheimer's disease (AD) and mild cognitive impairment (MCI of the Alzheimer's type). Dual-task involved a simultaneous execution of a sensor-based upper-extremity function (UEF) motor task (normal or rapid speed) and a cognitive task of counting numbers backward (by ones or threes). Motor function speed and variability were recorded and compared between cognitive groups using ANOVAs, adjusted for age, gender, and body mass index. Cognitive indexes were developed using multivariable ordinal logistic models to predict the cognitive status using UEF parameters. Ninety-one participants were recruited; 35 cognitive normal (CN, age = 83.8 ± 6.9), 34 MCI (age = 83.9 ± 6.6), and 22 AD (age = 84.1 ± 6.1). Flexion number and sensor-based motion variability parameters, within the normal pace elbow flexion, showed significant between-group differences (maximum effect size of 1.10 for CN versus MCI and 1.39 for CN versus AD, p < 0.0001). Using these parameters, the cognitive status (both MCI and AD) was predicted with a receiver operating characteristic area under curve of 0.83 (sensitivity = 0.82 and specificity = 0.72). Findings suggest that measures of motor function speed and accuracy within a more practical upper-extremity test (instead of walking) may provide enough complexity for cognitive impairment assessment. Cognitive impairment is a critical health problem with an increasing prevalence because of the population aging 1. It is estimated that by 2040, the number of elders living with dementia will surpass nine million in the US, roughly 170% increase compared to 2001 2. Among different types of dementia, Alzheimer's disease (AD) is the most common type, which influences the lives of up to 7% of the elderly population in the US and globally 3. Early dementia screening provides an opportunity to begin secondary prevention, as well as planning for future care, safety concerns, and financial and legal arrangements, while decision-making capacity remains 4. Unfortunately, many providers are reluctant to screen for dementia resulting in less than half of patients with AD having ever received a formal diagnosis 5. The current research was founded based on the fact that simultaneous declines in motor and cognitive performance occur with aging 6-8. In many age-related neurodegenerative diseases, and more specifically in Alzheimer's disease, compensatory processes in cortical and subcortical brain regions allow maintenance of motor and cognitive performance 9. Assessing deficits in dual-tasking, therefore, can provide a powerful tool for screening cognitive impairments. Gait has been commonly used as the motor task component in dual-task assessments. Poor dual-task gait performance has been significantly correlated with decreased executive and neuropsychological function, and demonstrated to be associated with AD or even mild cognitive impairment (MCI) 10-12. However, many older adults have mobility impairments, and many clinics lack adequate space to safely perform gait measures.

Circulation, 2019

Background: Fall injuries are responsible for significant health care utilization, disability, lo... more Background: Fall injuries are responsible for significant health care utilization, disability, loss of independence, and high costs among community-dwelling older adults with cardiovascular disease risk factors (CVD-RF). A Matter of Balance (MOB) is a national community-based fall prevention program, which focuses on cognitive restructuring to manage concerns about falling, but does not include a balance-training component. We hypothesize if MOB added to a dual-task balance challenge (DTBC) comprising weight transfer using fixed and random ordering of ankle reaching tasks, while simultaneously challenging attention—would lead to reduced fall risk. Objectives: To assess participants’ acceptance and satisfaction with the 4-week MOB and MOB plus DTBC interventions, safety and adherence, and examine changes in fall risk (balance, gait, and fear of falling) post-intervention. Methods: A single-blind, two-group, randomized pilot study, among community-dwelling older adults with CVD-RF at ...

Journal of Voice, 2018

The purpose of the current study is to determine the relation of frailty syndrome to acoustic mea... more The purpose of the current study is to determine the relation of frailty syndrome to acoustic measures of voice quality and voice-related handicap. Methods: Seventy-three adults (52 community-dwelling participants and 21 assisted living residents) ages 60 and older completed frailty screening, acoustic assessment, cognitive screening, and the Voice-Handicap Index-10 (VHI-10). Factor analysis was used to consolidate acoustic measures. Statistical analysis included multiple regression, Analysis of variance, and Tukey post-hoc tests with alpha of 0.05. Results: MoCA ® and exhaustion explained 28% of the variance in VHI-10. MoCA ® and sex explained 27% of the variance in Factor 1 (spectral ratio), age and MoCA ® explained 13% of the variance in Factor 2 (CPP for speech), and slowness explained 10% of the variance in Factor 3 (CPP for sustained /a/). There were statistically significant differences in two measures across frailty groups: VHI-10 and MoCA ®. Acoustic factor scores did not differ significantly among frailty groups (p > .05). Conclusions: Voice-related handicap and cognitive status differed among robust and frail older adults, yet vocal function measures did not. The components of frailty most related to VHI-10 were exhaustion and weight loss rather than slowness, weakness, or inactivity. Based on these findings, routine screening of physical frailty and cognition are recommended as part of a complete voice evaluation for older adults.

BioMedical Engineering OnLine, 2018

Background Nearly 30% of older adults over 65 experience one or more falls every year, leading to... more Background Nearly 30% of older adults over 65 experience one or more falls every year, leading to hospitalization and death [1, 2]. The first step to prevent fall is to identify high fall risk individuals and understand the underlying mechanism that can lead to fall. Human balancing is a complex mechanism that involves several physiological systems, including sensory units (i.e., vestibular, visual, and proprioceptive), muscle reflexes, and the central nervous system [3, 4]. Any deterioration in components of this mechanism or interactions between components can compromise postural balance. As a result of aging,

Journal of Clinical Sleep Medicine, 2017

Study Objectives: To improve sleep quality assessment using a single chest-worn sensor by extract... more Study Objectives: To improve sleep quality assessment using a single chest-worn sensor by extracting body acceleration and sleep position changes. Methods: Sleep patterns of 21 participants (50.8 ± 12.8 years, 47.8% female) with self-reported sleep problems were simultaneously recorded using a chest sensor (Chest), an Actiwatch (Wrist), and polysomnography (PSG) during overnight sleep laboratory assessment. An algorithm for Chest was developed to detect sleep/wake epochs based on body acceleration and sleep position/postural changes data, which were then used to estimate sleep parameters of interest. Comparisons between Chest and Wrist with respect to PSG were performed. Identification of sleep/wake epochs was assessed by estimating sensitivity, specificity, and accuracy. Agreement between sensor-derived sleep parameters and PSG was assessed using correlation coefficients and Bland-Altman analysis. Results: Chest identified sleep/wake epochs with an accuracy of on average 6% higher than Wrist (85.8% versus 79.8%). Similar trends were observed for sensitivity/specificity values. Correlation between Wrist and PSG was poor for most of the sleep parameters of interest (r = 0.0-0.3); however, Chest and PSG correlation showed moderate to strong agreement (r = 0.4-0.8) with relatively low bias and high precision bias (precision): 9.2 (13.2) minutes for sleep onset latency; 17.3(34.8) minutes for total sleep time; 7.5 (29.8) minutes for wake after sleep onset; and 2.0 (7.3)% for sleep efficacy. Conclusions: Combination of sleep postural/position changes and body acceleration improved detection of sleep/wake epochs compared to wrist acceleration alone. The chest sensors also improved estimation of sleep parameters of interest with stronger agreement with PSG. Our findings may expand the application of wearable sensors to clinically assess sleep outside of a sleep laboratory.

Archives of Gerontology and Geriatrics, 2021

BACKGROUND Although previous studies showed that frail older adults are more susceptible to devel... more BACKGROUND Although previous studies showed that frail older adults are more susceptible to develop cardiovascular diseases, the underlying effect of frailty on heart rate dynamics is still unclear. The goal of the current study was to measure heart rate changes due to normal speed and rapid walking among non-frail and pre-frail/frail older adults, and to implement heart rate dynamic measures to identify frailty status. METHODS Eighty-eight older adults (≥65 years) were recruited and stratified into frailty groups based on the five-component Fried frailty phenotype. While performing gait tests, heart rate was recorded using a wearable ECG and accelerometer sensors. Groups consisted of 27 non-frail (age = 78.70 ± 7.32) and 61 pre-frail/frail individuals (age = 81.00 ± 8.14). The parameters of interest included baseline heart rate measures (mean heart rate and heart rate variability), and heart rate dynamics due to walking (percentage change in heart rate and required time to reach the maximum heart rate). RESULTS Respectively for normal and rapid walking conditions, pre-frail/frail participants had 46% and 44% less increase in heart rate, and 49% and 27% slower occurrence of heart rate peak, when compared to non-frail older adults (p < 0.04, effect size = 0.71 ± 0.12). Measures of heart rate dynamics showed stronger associations with frailty status compared to baseline resting-state measures (sensitivity = 0.75 and specificity = 0.65 using heart rate dynamics measures, compared to sensitivity = 0.64 and specificity = 0.62 using baseline parameters). CONCLUSIONS These findings suggest that measures of heart rate dynamics in response to daily activities may provide meaningful markers for frailty screening.

Additional file 1: Supplementary Table 1(a-d). Gait performance parameters for 20s, 30s, 40s and ... more Additional file 1: Supplementary Table 1(a-d). Gait performance parameters for 20s, 30s, 40s and 50s continuous walks, one-way ANOVA results, and Cohen's d effect sizes between non-frail(N) and pre-frail(P)/frail(F) groups; Supplementary Table 2. Logistic model performance comparison using gait performance parameters between different duration of continuous walks for 80% specificity.

2016 Computing in Cardiology Conference (CinC), 2016

Uni-channel ECG was recorded using a wearablesensor in 45 female elders aged 65 and above. Partic... more Uni-channel ECG was recorded using a wearablesensor in 45 female elders aged 65 and above. Participants were categorized as non-fallers (n=22) and fallers (n=23) based on historical report of falling in the last 12 month. For data analysis, PVC episodes were extracted using an automatic code developed in Matlab, and checked manually by an expert to ensure accuracy. Number of PVC episodes per hour was extracted as the parameter of interest in this study and compared between fallers and non-fallers using analysis of variance (ANOVA) test. Number of PVC episodes per hour was not significantly different (p>0.05) between non-fallers (41.65±74.22) and fallers (43.62±59.48). In this study, the association of PVC frequency with fall risk and fear of fall was also studied; Number of PVC episodes were higher in high fall risk compared to low fall risk, and in high concern of fall compared to low concern of fall (p>0.05).

PRISMA checklist. (DOCX 22Â kb)

Heart failure (HF) is a common clinical syndrome in older adults, accounting for over 1 million a... more Heart failure (HF) is a common clinical syndrome in older adults, accounting for over 1 million annual hospitalizations, most of which are considered preventable. It also has the highest 30-day hospital readmission rate of any medical condition. Given the growing aging population, increasing lifespan, and longer survival with cardiac disorders, systematic and cost-effective approaches to outpatient HF management must be implemented to reduce readmissions. This edition of Elder Care will review some of those approaches. Daily Monitoring and Targeted Intervention Education should be provided about daily monitoring for the signs/symptoms of worsening HF. Patients/caregivers should be taught about early signs and symptoms of HF exacerbation that often occur in the days and weeks prior to re-hospitalization (Table 1). Interventions can then be made to stabilize the patient to reduce the risk of rehospitalization.

2016 Computing in Cardiology Conference (CinC), 2016

An increased prevalence of ventricular ectopy (Premature Ventricular Contraction, PVC) is associa... more An increased prevalence of ventricular ectopy (Premature Ventricular Contraction, PVC) is associated with increased incidence of congestive heart failure and increased mortality. Increase in incidence of ventricular ectopy with age has been demonstrated in previous studies, but to the best of our knowledge, its association with frailty, a geriatric syndrome that is associated with adverse health outcomes, has not been studied. The aim of this study was to assess the prevalence of ventricular ectopy in older adults across different frailty levels. A uni-channel ECG in 45 older adults aged 65 and above were measured using a wearable ECG recorder. Participants were classified as non-frail (n=22), pre-frail (n=17), and frail (n=6) using the Fried frailty phenotype. PVCs were identified automatically, and subsequently checked manually by an expert to ensure accuracy. Number of PVC beats per hour was considered for ECG assessment and analysis of variance (ANOVA) test was used to evaluate ...

Journal of the American Geriatrics Society, 2016

Human Movement Science, 2021

Studying the dynamics of nonlinear systems can provide additional information about the variabili... more Studying the dynamics of nonlinear systems can provide additional information about the variability structure of the system. Within the current study, we examined the application of regularity and local stability measures to capture motor function alterations due to dual-tasking using a previously validated upper-extremity function (UEF). We targeted young (ages 18 and 30 years) and older adults (65 years or older) with normal cognition based on clinical screening. UEF involved repetitive elbow flexion without counting (ST) and while counting backward by one (DT1) or three (DT3). We measured the regularity (measured by sample entropy (SE)), local stability (measured by the largest Lyapunov exponent (LyE)), as well as conventional peak-dependent variability measures (coefficient of variation of kinematics parameters) to capture motor dynamic alterations due to dual-tasking. Within both groups, only SE showed significant differences between all pairs of UEF condition comparisons, even ST vs DT1 (p = 0.007, effect size = 0.507), for which no peak-dependent parameter showed significant difference. Among all measures, the only parameter that showed a significant difference between young and older adults was LyE (p < 0.001, effect size = 0.453). Current findings highlight the potential of nonlinear analysis to detect aging-related alterations among cognitively healthy participants.

Aging Clinical and Experimental Research, 2020

Background While sensor-based daily physical activity (DPA) gait assessment has been demonstrated... more Background While sensor-based daily physical activity (DPA) gait assessment has been demonstrated to be an effective measure of physical frailty and fall-risk, the repeatability of DPA gait parameters between different days of measurement is not clear. Aims To evaluate test-retest reliability (repeatability) of DPA gait performance parameters, representing the quality of walking, and quantitative gait measures (e.g. number of steps) between two separate days of assessment among older adults. Methods DPA was acquired for 48-h from older adults (age ≥ 65 years) using a tri-axial accelerometer. Continuous walking bouts (≥ 60 s) were identified from acceleration data and used to extract gait performance parameters, including time-and frequency-domain gait parameters, representing walking speed, variability, and irregularity. To assess repeatability, intraclass correlation coefficient (ICC) was calculated using two-way mixed effects F-test models for day-1 vs. day-2 as the independent random effect. Repeatability tests were performed for all participants and also within frailty groups (non-frail and pre-frail/ frail identified using Fried phenotype). Results Data was analyzed from 63 older adults (29 non-frail and 34 pre-frail/frail). Most of the time-and frequency-domain gait performance parameters showed good to excellent repeatability (ICC ≥ 0.70), while quantitative parameters, including number of steps and walking duration showed poor repeatability (ICC < 0.30). Among majority of the gait performance parameters, we observed higher repeatability among the pre-frail/frail group (ICC > 0.78) compared to non-frail individuals (0.39 < ICC < 0.55). Conclusion Gait performance parameters, showed higher repeatability compared to quantitative measures. Higher repeatability among pre-frail/frail individuals may be attributed to a reduced functional capacity for performing more intense and variable physical tasks. Trial registration The clinical trial was retrospectively registered on June 18th, 2013 with ClinicalTrials.gov, identifier NCT01880229.

Alzheimer's & Dementia, 2018

Alzheimer's & Dementia, 2019

Alzheimer's & Dementia, 2019

Journal of Surgical Research, 2019

Background: Available methods for determining outcomes in vascular surgery patients are often sub... more Background: Available methods for determining outcomes in vascular surgery patients are often subjective or not applicable in nonambulatory patients. The purpose of the present study was to assess the association between vascular surgery outcomes and a previously validated upper-extremity function (UEF) method, which incorporates wearable motion sensors for the physical frailty assessment. Materials and methods: Patients (!50 y old) undergoing vascular surgery were recruited. Participants performed the 20-s UEF test, which involved rapid elbow flexion. This technology quantifies physical frailty features including slowness, weakness, exhaustion, and flexibility, which allows grouping individuals into nonfrail, prefrail, and frail categories. Surgical outcomes included length of hospital stay, discharged disposition, and 30d mortality, complications, readmission, and reintervention(s). Associations between outcomes and frailty were assessed using nominal logistic regression models, adjusted for age, gender, body mass index, and wound classification. Results: Thirty-seven participants were recruited: eight nonfrail (age ¼ 62.0 AE 10.6); 22 prefrail (age ¼ 65.6 AE 11.6); and seven frail (age ¼ 68.0 AE 8.0). Significant associations were observed between frailty and length of hospital stay (three times longer among frail participants, P ¼ 0.03), mortality after surgery (two incidents among frail participants, P < 0.01), and adverse discharge disposition (all nonfrail patients were discharged home, whereas only 43% of frail patients discharged home, P ¼ 0.01). Conclusions: This is the first study to validate the utility of UEF among patients undergoing any vascular surgery. Findings suggest that UEF may provide an objective and simple approach for assessing frailty to predict adverse events after vascular surgery, especially for nonambulatory patients.

Background Frailty is an increasingly recognized geriatric syndrome resulting in decline in reser... more Background Frailty is an increasingly recognized geriatric syndrome resulting in decline in reserve across multiple physiological systems. Impaired physical function is a prime indicator of frailty.Objective The goal of this study was to develop an algorithm that discriminates between frailty groups (non-frail, pre-frail, and frail) based on gait performance parameters derived from unsupervised daily physical activity (DPA).Methods DPA was acquired for 48 hours from older adults (≥65 years) using a tri-axial accelerometer motion-sensor. Purposeful continuous bouts of walking (≥60s) without pauses were identified from acceleration data. These were then used to extract qualitative measures (gait variability, gait asymmetry, and gait irregularity) and quantitative measures (total continuous walking duration and maximum number of continuous steps) to characterize gait performance. Association between frailty and gait performance parameters was assessed using multinomial logistic models ...

Gerontology & Geriatrics Education, 2018

As the U.S. population ages and lives longer, we need to assure that future providers are prepare... more As the U.S. population ages and lives longer, we need to assure that future providers are prepared to work in highly functioning interprofessional teams to deliver person-centered care for older adults with complex chronic conditions. Assisted living facilities are ideal venues in which to train interprofessional health sciences students in providing such care. After monthly clinics involving interprofessional students (from the colleges of medicine, nursing, pharmacy, public health, and school of social work) providing team-based care to older adults, students' post-clinic evaluations indicated perceived improvements in knowledge, attitudes, and perceptions about aging and care of older adults. In addition, participating older adults reported improved self-worth and enjoyment. The curriculum, evaluation outcomes, and lessons learned are described to support program replication.

Scientific Reports, 2019

The purpose of the current study was to develop an objective tool based on dual-task performance ... more The purpose of the current study was to develop an objective tool based on dual-task performance for screening early-stage Alzheimer's disease (AD) and mild cognitive impairment (MCI of the Alzheimer's type). Dual-task involved a simultaneous execution of a sensor-based upper-extremity function (UEF) motor task (normal or rapid speed) and a cognitive task of counting numbers backward (by ones or threes). Motor function speed and variability were recorded and compared between cognitive groups using ANOVAs, adjusted for age, gender, and body mass index. Cognitive indexes were developed using multivariable ordinal logistic models to predict the cognitive status using UEF parameters. Ninety-one participants were recruited; 35 cognitive normal (CN, age = 83.8 ± 6.9), 34 MCI (age = 83.9 ± 6.6), and 22 AD (age = 84.1 ± 6.1). Flexion number and sensor-based motion variability parameters, within the normal pace elbow flexion, showed significant between-group differences (maximum effect size of 1.10 for CN versus MCI and 1.39 for CN versus AD, p < 0.0001). Using these parameters, the cognitive status (both MCI and AD) was predicted with a receiver operating characteristic area under curve of 0.83 (sensitivity = 0.82 and specificity = 0.72). Findings suggest that measures of motor function speed and accuracy within a more practical upper-extremity test (instead of walking) may provide enough complexity for cognitive impairment assessment. Cognitive impairment is a critical health problem with an increasing prevalence because of the population aging 1. It is estimated that by 2040, the number of elders living with dementia will surpass nine million in the US, roughly 170% increase compared to 2001 2. Among different types of dementia, Alzheimer's disease (AD) is the most common type, which influences the lives of up to 7% of the elderly population in the US and globally 3. Early dementia screening provides an opportunity to begin secondary prevention, as well as planning for future care, safety concerns, and financial and legal arrangements, while decision-making capacity remains 4. Unfortunately, many providers are reluctant to screen for dementia resulting in less than half of patients with AD having ever received a formal diagnosis 5. The current research was founded based on the fact that simultaneous declines in motor and cognitive performance occur with aging 6-8. In many age-related neurodegenerative diseases, and more specifically in Alzheimer's disease, compensatory processes in cortical and subcortical brain regions allow maintenance of motor and cognitive performance 9. Assessing deficits in dual-tasking, therefore, can provide a powerful tool for screening cognitive impairments. Gait has been commonly used as the motor task component in dual-task assessments. Poor dual-task gait performance has been significantly correlated with decreased executive and neuropsychological function, and demonstrated to be associated with AD or even mild cognitive impairment (MCI) 10-12. However, many older adults have mobility impairments, and many clinics lack adequate space to safely perform gait measures.

Circulation, 2019

Background: Fall injuries are responsible for significant health care utilization, disability, lo... more Background: Fall injuries are responsible for significant health care utilization, disability, loss of independence, and high costs among community-dwelling older adults with cardiovascular disease risk factors (CVD-RF). A Matter of Balance (MOB) is a national community-based fall prevention program, which focuses on cognitive restructuring to manage concerns about falling, but does not include a balance-training component. We hypothesize if MOB added to a dual-task balance challenge (DTBC) comprising weight transfer using fixed and random ordering of ankle reaching tasks, while simultaneously challenging attention—would lead to reduced fall risk. Objectives: To assess participants’ acceptance and satisfaction with the 4-week MOB and MOB plus DTBC interventions, safety and adherence, and examine changes in fall risk (balance, gait, and fear of falling) post-intervention. Methods: A single-blind, two-group, randomized pilot study, among community-dwelling older adults with CVD-RF at ...

Journal of Voice, 2018

The purpose of the current study is to determine the relation of frailty syndrome to acoustic mea... more The purpose of the current study is to determine the relation of frailty syndrome to acoustic measures of voice quality and voice-related handicap. Methods: Seventy-three adults (52 community-dwelling participants and 21 assisted living residents) ages 60 and older completed frailty screening, acoustic assessment, cognitive screening, and the Voice-Handicap Index-10 (VHI-10). Factor analysis was used to consolidate acoustic measures. Statistical analysis included multiple regression, Analysis of variance, and Tukey post-hoc tests with alpha of 0.05. Results: MoCA ® and exhaustion explained 28% of the variance in VHI-10. MoCA ® and sex explained 27% of the variance in Factor 1 (spectral ratio), age and MoCA ® explained 13% of the variance in Factor 2 (CPP for speech), and slowness explained 10% of the variance in Factor 3 (CPP for sustained /a/). There were statistically significant differences in two measures across frailty groups: VHI-10 and MoCA ®. Acoustic factor scores did not differ significantly among frailty groups (p > .05). Conclusions: Voice-related handicap and cognitive status differed among robust and frail older adults, yet vocal function measures did not. The components of frailty most related to VHI-10 were exhaustion and weight loss rather than slowness, weakness, or inactivity. Based on these findings, routine screening of physical frailty and cognition are recommended as part of a complete voice evaluation for older adults.

BioMedical Engineering OnLine, 2018

Background Nearly 30% of older adults over 65 experience one or more falls every year, leading to... more Background Nearly 30% of older adults over 65 experience one or more falls every year, leading to hospitalization and death [1, 2]. The first step to prevent fall is to identify high fall risk individuals and understand the underlying mechanism that can lead to fall. Human balancing is a complex mechanism that involves several physiological systems, including sensory units (i.e., vestibular, visual, and proprioceptive), muscle reflexes, and the central nervous system [3, 4]. Any deterioration in components of this mechanism or interactions between components can compromise postural balance. As a result of aging,

Journal of Clinical Sleep Medicine, 2017

Study Objectives: To improve sleep quality assessment using a single chest-worn sensor by extract... more Study Objectives: To improve sleep quality assessment using a single chest-worn sensor by extracting body acceleration and sleep position changes. Methods: Sleep patterns of 21 participants (50.8 ± 12.8 years, 47.8% female) with self-reported sleep problems were simultaneously recorded using a chest sensor (Chest), an Actiwatch (Wrist), and polysomnography (PSG) during overnight sleep laboratory assessment. An algorithm for Chest was developed to detect sleep/wake epochs based on body acceleration and sleep position/postural changes data, which were then used to estimate sleep parameters of interest. Comparisons between Chest and Wrist with respect to PSG were performed. Identification of sleep/wake epochs was assessed by estimating sensitivity, specificity, and accuracy. Agreement between sensor-derived sleep parameters and PSG was assessed using correlation coefficients and Bland-Altman analysis. Results: Chest identified sleep/wake epochs with an accuracy of on average 6% higher than Wrist (85.8% versus 79.8%). Similar trends were observed for sensitivity/specificity values. Correlation between Wrist and PSG was poor for most of the sleep parameters of interest (r = 0.0-0.3); however, Chest and PSG correlation showed moderate to strong agreement (r = 0.4-0.8) with relatively low bias and high precision bias (precision): 9.2 (13.2) minutes for sleep onset latency; 17.3(34.8) minutes for total sleep time; 7.5 (29.8) minutes for wake after sleep onset; and 2.0 (7.3)% for sleep efficacy. Conclusions: Combination of sleep postural/position changes and body acceleration improved detection of sleep/wake epochs compared to wrist acceleration alone. The chest sensors also improved estimation of sleep parameters of interest with stronger agreement with PSG. Our findings may expand the application of wearable sensors to clinically assess sleep outside of a sleep laboratory.