Sensor-Based Assessment of Variability in Daily Physical Activity and Frailty.

INTRODUCTION: Frailty is a common geriatric syndrome associated with decline in physiological reserve. While several digital biomarkers of daily physical activity (DPA) have been used in frailty assessment, the association between DPA variability and frailty is still not clear. The goal of this study was to determine the association between frailty and DPA variability. METHODS: This is an observational cross-sectional study conducted between September 2012 and November 2013. Older adults (≥65 years), without any severe mobility disorder, and the ability to walk 10 m (with or without an assistive device) were eligible for the study. DPA including sitting, standing, walking, lying, and postural transition were recorded for 48 h continuously. DPA variability was analyzed from two perspectives: (i) DPA duration variability in terms of coefficient of variation (CoV) of sitting, standing, walking, and lying down durations; and (ii) DPA performance variability in terms of CoV of sit-to-stand (SiSt) and stand-to-sit (StSi) durations and stride time (i.e., slope of power spectral density - PSD). RESULTS: Data was analyzed from 126 participants (44 non-frail, 60 pre-frail, and 22 frail). For DPA duration variability, CoV of lying and walking duration was significantly larger among non-frail compared to pre-frail and frail groups (p < 0.03, d = 0.89 ± 0.40). For DPA performance variability, StSi CoV and PSD slope were significantly smaller for non-frail compared to pre-frail and frail groups (p < 0.05, d = 0.78 ± 0.19). CONCLUSION: Lower DPA duration variability in pre-frail and frail groups may be attributed to the set daily routines frail older adults tend to follow, compared to variable physical activity routines of non-frail older adults. Higher DPA performance variability in the frail group may be attributed to reduced physiological capabilities toward walking for longer durations and the reduced muscle strength in the lower extremities, leading to incosistency in performing postural transitions.

Frailty assessment using a novel approach based on combined motor and cardiac functions: a pilot study.

BACKGROUND: Previous research showed association between frailty and an impaired autonomic nervous system; however, the direct effect of frailty on heart rate (HR) behavior during physical activity is unclear. The purpose of the current study was to determine the association between HR increase and decrease with frailty during a localized upper-extremity function (UEF) task to establish a multimodal frailty test. METHODS: Older adults aged 65 or older were recruited and performed the UEF task of rapid elbow flexion for 20 s with the right arm. Wearable gyroscopes were used to measure forearm and upper-arm motion, and electrocardiography were recorded using leads on the left chest. Using this setup, HR dynamics were measured, including time to peak HR, recovery time, percentage increase in HR during UEF, and percentage decrease in HR during recovery after UEF. RESULTS: Fifty-six eligible participants were recruited, including 12 non-frail (age = 76.92 ± 7.32 years), and 40 pre-frail (age = 80.53 ± 8.12 years), and four frail individuals (age = 88.25 ± 4.43 years). Analysis of variance models showed that the percentage increase in HR during UEF and percentage decrease in HR during recovery were both 47% smaller in pre-frail/frail older adults compared to non-frails (p < 0.01, effect size = 0.70 and 0.62 for increase and decrease percentages). Using logistic models with both UEF kinematics and HR parameters as independent variables, frailty was predicted with a sensitivity of 0.82 and specificity of 0.83. CONCLUSION: Current findings showed evidence of strong association between HR dynamics and frailty. It is suggested that combining kinematics and HR data in a multimodal model may provide a promising objective tool for frailty assessment.

Physical and Cognitive Function Assessment to Predict Postoperative Outcomes of Abdominal Surgery.

BACKGROUND: Current evaluation methods to assess physical and cognitive function are limited and often not feasible in emergency settings. The upper-extremity function (UEF) test to assess physical and cognitive performance using wearable sensors. The purpose of this study was to examine the (1) relationship between preoperative UEF scores with in-hospital outcomes; and (2) association between postoperative UEF scores with 30-d adverse outcomes among adults undergoing emergent abdominal surgery. METHODS: We performed an observational, longitudinal study among adults older than 40 y who presented with intra-abdominal symptoms. The UEF tests included a 20-sec rapid repetitive elbow flexion (physical function), and a 60-sec repetitive elbow flexion at a self-selected pace while counting backwards by threes (cognitive function), administered within 24-h of admission and within 24-h prior to discharge. Multiple logistic regression models assessed the association between UEF and outcomes. Each model consisted of the in-hospital or 30-d post-discharge outcome as the dependent variable, preoperative UEF physical and cognitive scores as hypothesis covariates, and age and sex as adjuster covariates. RESULTS: Using UEF physical and cognitive scores to predict in-hospital outcomes, an area under curve (AUC) of 0.76 was achieved, which was 17% more sensitive when compared to age independently. For 30-d outcomes, the AUC increased to 0.89 when UEF physical and cognitive scores were included in the model with age and sex. DISCUSSION: Sensor-based measures of physical and cognitive function enhance outcome prediction providing an objective practicable tool for risk stratification in emergency surgery settings among aging adults presenting with intra-abdominal symptoms.

Between-day repeatability of sensor-based in-home gait assessment among older adults: assessing the effect of frailty.

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.

Sensor-Based Upper-Extremity Frailty Assessment for the Vascular Surgery Risk Stratification.

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 30-d 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 = 62.0 ± 10.6); 22 prefrail (age = 65.6 ± 11.6); and seven frail (age = 68.0 ± 8.0). Significant associations were observed between frailty and length of hospital stay (three times longer among frail participants, P = 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 = 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.

Sensor-based characterization of daily walking: a new paradigm in pre-frailty/frailty assessment.

BACKGROUND: Frailty is a highly recognized geriatric syndrome resulting in decline in reserve across multiple physiological systems. Impaired physical function is one of the major indicators of frailty. The goal of this study was to evaluate an algorithm that discriminates between frailty groups (non-frail and pre-frail/frail) based on gait performance parameters derived from unsupervised daily physical activity (DPA). METHODS: DPA was acquired for 48 h from older adults (≥65 years) using a tri-axial accelerometer motion-sensor. Continuous bouts of walking for 20s, 30s, 40s, 50s and 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 with frailty as the dependent variable, and gait performance parameters along with demographic parameters as independent variables. RESULTS: One hundred twenty-six older adults (44 non-frail, 60 pre-frail, and 22 frail, based on the Fried index) were recruited. Step- and stride-times, frequency domain gait variability, and continuous walking quantitative measures were significantly different between non-frail and pre-frail/frail groups (p < 0.05). Among the five different durations (20s, 30s, 40s, 50s and 60s), gait performance parameters extracted from 60s continuous walks provided the best frailty assessment results. Using the 60s gait performance parameters in the logistic model, pre-frail/frail group (vs. non-frail) was identified with 76.8% sensitivity and 80% specificity. DISCUSSION: Everyday walking characteristics were found to be associated with frailty. Along with quantitative measures of physical activity, qualitative measures are critical elements representing the early stages of frailty. In-home gait assessment offers an opportunity to screen for and monitor frailty. TRIAL REGISTRATION: The clinical trial was retrospectively registered on June 18th, 2013 with ClinicalTrials.gov, identifier NCT01880229.

Proprioceptive impairments in high fall risk older adults: the effect of mechanical calf vibration on postural balance.

BACKGROUND: Impairments in proprioceptive mechanism with aging has been observed and associated with fall risk. The purpose of the current study was to assess proprioceptive deficits among high fall risk individuals in comparison with healthy participants, when postural performance was disturbed using low-frequency mechanical gastrocnemius vibratory stimulation. METHODS: Three groups of participants were recruited: healthy young (n = 10; age = 23 ± 2 years), healthy elders (n = 10; age = 73 ± 3 years), and high fall risk elders (n = 10; age = 84 ± 9 years). Eyes-open and eyes-closed upright standing balance performance was measured with no vibration, and 30 and 40 Hz vibration of both calves. Vibration-induced changes in balance behaviors, compared to baseline (no vibratory stimulation) were compared between three groups using multivariable repeated measures analysis of variance models. RESULTS: Overall, similar results were observed for two vibration frequencies. However, changes in body sway due to vibration were more obvious within the eyes-closed condition, and in the medial-lateral direction. Within the eyes-closed condition high fall risk participants showed 83% less vibration-induced change in medial-lateral body sway, and 58% less sway velocity, when compared to healthy participants (p < 0.001; effect size = 0.45-0.64). CONCLUSIONS: The observed differences in vibration effects on balance performance may be explained by reduced sensitivity in peripheral nervous system among older adults with impaired balance.

Frailty Assessment Predicts Acute Outcomes in Patients Undergoing Screening Colonoscopy.

BACKGROUND: Colonoscopy is associated with multiple adverse outcomes. With an aging population undergoing colorectal cancer screening, few modalities exist to assess the patient risk prior to colonoscopy. Frailty, the age-related decline in reserve and function across multiple organ systems, predicts poor surgical outcomes, but its role in endoscopy is unclear. AIMS: This prospective cohort study assesses the efficacy of frailty in predicting acute colonoscopy outcomes. METHODS: Participants aged ≥ 50 years undergoing screening colonoscopy at a tertiary care center were recruited over 2 months ending in July 2017. Frailty was assessed using a validated 20-s upper-extremity frailty test, which measures the capacity of muscle performance. Demographic data, American Society of Anesthesiologists (ASA) status, and Charlson comorbidity index (CCI) were evaluated. Procedure-related adverse events and cardiopulmonary changes during and in the immediate post-procedure period were recorded. Adverse events were stratified into minor and major events. Chi-square and ANCOVA models were used in the analysis. RESULTS: Ninety-nine adults (mean age 62.8 years) were enrolled, among which 49 were non-frail and 50 were pre-frail/frail; 50 were female. Overall, 55 participants experienced a total of 87 adverse events. Frailty and ASA status were significantly associated with colonoscopy adverse events (p = 0.01 and p = 0.02, respectively). Age and CCI did not predict colonoscopy outcomes. CONCLUSIONS: Compared to age and CCI, frailty status better predicts colonoscopy outcomes in older adults. Among adults undergoing colonoscopy, routine frailty screening should be considered for risk stratification. Additional prospective studies evaluating frailty measurements in endoscopy will further clarify its role in forecasting adverse events.

The Effect of Pain Relief on Daily Physical Activity: In-Home Objective Physical Activity Assessment in Chronic Low Back Pain Patients after Paravertebral Spinal Block.

This study evaluates the effect of paravertebral spinal injection (PSI), utilizing both subjective and objective assessments in chronic low back pain (LBP) associated with facet joint arthrosis over a one-month duration. Subjective questionnaires included the visual analogue scale (VAS) for pain, the Oswestry Disability Index, the Health Survey SF-12, and the short Falls Efficacy Scale International (FES-I). Objective assessments included in-clinic gait and Timed Up and Go (TUG) tests using wearable sensors, as well as 48 h daily physical activity (DPA) monitored using a chest-worn triaxial accelerometer. Subjective and objective measures were performed prior to treatment, immediately after the treatment, and one month after the treatment. Eight LBP patients were recruited for this study (mean age = 54 ± 13 years, body mass index = 31.41 ± 6.52 kg/m², 50% males). Results show significant decrease in pain (~55%, p < 0.05) and disability (Oswestry scores, ~21%, p < 0.05). In-clinic gait and TUG were also significantly improved (~16% and ~18% faster walking and shorter TUG, p < 0.05); however, DPA, including the percentage of physical activities (walking and standing) and the number of steps, showed no significant change after PSI (p > 0.25; effect size ≤ 0.44). We hypothesize that DPA may continue to be truncated to an extent by conditioned fear-avoidance, a psychological state that may prevent increase in daily physical activity to avoid pain.

Postural Transitions during Activities of Daily Living Could Identify Frailty Status: Application of Wearable Technology to Identify Frailty during Unsupervised Condition.

BACKGROUND: Impairment of physical function is a major indicator of frailty. Functional performance tests have been shown to be useful for identification of frailty in older adults. However, these tests are often not translatable into unsupervised and remote monitoring of frailty status at home and/or community settings. OBJECTIVE: In this study, we explored daily postural transition quantified using a chest-worn wearable technology to identify frailty in community-dwelling older adults. METHODS: Spontaneous daily physical activity was monitored over 24 h in 120 community-dwelling elderly (age: 78 ± 8 years) using an unobtrusive wearable sensor (PAMSys™, BioSensics LLC, Watertown, MA, USA). Participants were classified as non-frail and pre-frail/frail using Fried's criteria. A validated software package was used to identify body postures and postural transition between each independent postural activity such as sit-to-stand, stand-to-sit, stand-to-walk, and walk-to-stand. The transition from walking to sitting was further classified as quick sitting and cautious sitting based on presence/absence of a standing posture pause between sitting and walking. A general linear model univariate test was used for between-group comparison. Pearson's correlation was used to determine the association between sensor-derived parameters and age. Logistic regression model was used to identify independent predictors of frailty. RESULTS: According to Fried's criteria, 63% of participants were pre-frail/frail. The total number of postural transitions, stand-to-walk, and walk-to-stand were, respectively, 25.2, 30.2, and 30.6% lower in the pre-frail/frail group when compared to the non-frail group (p < 0.05, Cohen's d = 0.73-0.79). Furthermore, the ratio of cautious sitting was significantly higher by 6.2% in pre-frail/frail compared to non-frail (p = 0.025, Cohen's d = 0.22). Total number of postural transitions and the ratio of cautious sitting also showed significant negative and positive correlations with age, respectively (r = -0.51 and 0.29, p < 0.05). After applying a logistic regression model, among tested parameters, walk-to-stand (odds ratio [OR] = 0.997 p = 0.013), quick sitting (OR = 1.036, p = 0.05), and age (OR = 1.073, p = 0.016) were recognized as independent variables to identify frailty status. CONCLUSIONS: This study demonstrated that daily number of specific postural transitions such as walk-to-stand and quick sitting could be used for monitoring frailty status by unsupervised monitoring of daily physical activity. Further study is warranted to explore whether tracking the daily number of specific postural transitions is also sensitive to track change in the status of frailty over time.

Upper-Extremity Function Predicts Adverse Health Outcomes among Older Adults Hospitalized for Ground-Level Falls.

BACKGROUND: Despite National Surgical Quality Improvement guidelines to integrate frailty into surgical elder assessments, a quick, accurate, and simple frailty assessment tool suitable for busy clinical settings is still not available. Recently, we have demonstrated that a simple upper-extremity function (UEF) test based on wearable sensors could identify frailty with high agreement with conventional assessments by testing 20-s repetitive elbow flexion and extension. OBJECTIVE: We examined whether UEF parameters are sensitive for predicting adverse health outcomes in bedbound older adults admitted to hospital due to ground-level fall injuries. STUDY DESIGN: Frailty was assessed in 101 eligible older adults (age: 79 ± 9 years) admitted to a trauma setting using the UEF test at the time of admission. All participants were followed up for 2 months using phone calls and chart reviews. The measured health outcomes included (1) discharge disposition (favorable: discharge home or rehabilitation; unfavorable: discharge to skilled nursing facility or death), (2) hospital length of stay, (3) 30-day readmission, (4) 60-day readmission, and (5) 30-day prospective falls. Multivariate analyses were used to identify independent predictors of adverse health outcomes based on participants' demographic parameters (i.e., age, gender, and body mass index [BMI]) and UEF index. RESULTS: Based on the UEF frailty status, 53 (52%) of the participants were frail and 48 (48%) were non-frail. Among all adverse health outcomes, age was only a significant predictor of 30-day prospective falls (p = 0.023). On the other hand, the UEF index was a significant predictor of all measured outcomes except hospital length of stay (p < 0.010). Among the UEF parameters, those indicating slowness, weakness, and exhaustion had the highest effect sizes to predict an unfavorable discharge disposition (p < 0.010; effect size = 0.65-0.92). CONCLUSION: The results of this study suggest that a 20-s UEF test is practical in the trauma setting and could be used as a quick measure for predicting adverse events and outcomes among bedbound patients after discharge. Assessing frailty using UEF may assist in objective triage, treatment, and post-discharge decision-making with regard to geriatric trauma patients.

Frailty assessment in older adults using upper-extremity function: index development.

BACKGROUND: Numerous multidimensional assessment tools have been developed to measure frailty; however, the clinical feasibility of these tools is limited. We previously developed and validated an upper-extremity function (UEF) assessment method that incorporates wearable motion sensors. The purpose of the current study was to: 1) cross-sectionally validate the UEF method in a larger sample in comparison with the Fried index; 2) develop a UEF frailty index to predict frailty categories including non-frail, pre-frail, and frail based on UEF parameters and demographic information, using the Fried index as the gold standard; and 3) develop a UEF continuous score (points scores for each UEF parameter and a total frailty score) based on UEF parameters and demographic information, using the Fried index as the gold standard. METHODS: We performed a cross-sectional validation and index development study within the Banner Medical Center, Tucson, and Banner Sun Health Research Institute, Sun City, Arizona. Community-dwelling and outpatient older adults (≥60 years; n = 352; 132 non-frail, 175 pre-frail, and 45 frail based on Fried criteria) were recruited. For the UEF test, each participant performed a 20-s elbow flexion, within which they repetitively and rapidly flexed and extended their dominant elbow. Using elbow motion outcomes two UEF indexes were developed (categorical and score). The Fried index was measured as the gold standard. RESULTS: For the categorical index, speed of elbow flexion, elbow range of motion, elbow moment, number of flexion, speed variability and reduction within 20 s, as well as body mass index (BMI) were included as the pre-frailty/frailty predictor parameters. Results from 10-fold cross-validation showed receiver operator characteristic area under the curve of 0.77 ± 0.07 and 0.80 ± 0.12 for predicting Fried pre-frailty and frailty, respectively. UEF score (0.1 to 1.0) was developed using similar UEF parameters. CONCLUSIONS: We present an objective, sensor-based frailty assessment tool based on physical frailty features including slowness, weakness, exhaustion (muscle fatigue), and flexibility of upper-extremity movements. Within the current study, the method was validated cross-sectionally using the Fried index as the gold standard and the UEF categorical index and UEF frailty score were developed for research purposes and potentially for future clinical use.

Alterations in gait parameters with peripheral artery disease: The importance of pre-frailty as a confounding variable.

Although poor walking is the most common symptom of peripheral artery disease (PAD), reported results are inconsistent when comparing gait parameters between PAD patients and healthy controls. This inconsistency may be due to frailty, which is highly prevalent among PAD patients. To address this hypothesis, 41 participants, 17 PAD (74±8 years) and 24 aged-matched controls (76±7 years), were recruited. Gait was objectively assessed using validated wearable sensors. Analysis of covariate (ANCOVA) tests were used to compare gait parameters between PAD and non-PAD groups, considering age, gender, and body mass index as covariates, while stratified based on frailty status. According to the Fried frailty index, 47% of PAD and 50% of control participants were non-frail and the rest were classified as pre-frail. Within non-frail participants, gait speed, body sway during walking, stride length, gait cycle time, double-support, knee range of motion, speed variability, mid-swing speed, and gait initiation were significantly different between PAD and control groups (effect size d = 0.75±0.43). In the pre-frail group, however, most of the gait differences were diminished except for gait initiation and gait variability. Results suggest that gait initiation is the most sensitive parameter for detecting gait impairment in PAD participants when compared to controls, regardless of frailty status (d = 1.30-1.41; p<0.050). The observed interaction effect between frailty and PAD on gait parameters confirms the importance of assessing functionality in addition to age to provide more consistency in detecting motor performance impairments due to PAD.

Motor Performance and Physical Activity as Predictors of Prospective Falls in Community-Dwelling Older Adults by Frailty Level: Application of Wearable Technology.

BACKGROUND: Few studies of the association between prospective falls and sensor-based measures of motor performance and physical activity (PA) have evaluated subgroups of frailty status separately. OBJECTIVE: To evaluate wearable sensor-based measures of gait, balance, and PA that are predictive of future falls in community-dwelling older adults. METHODS: The Arizona Frailty Cohort Study in Tucson, Arizona, followed community-dwelling adults aged 65 years and over (without baseline cognitive deficit, severe movement disorders, or recent stroke) for falls over 6 months. Baseline measures included Fried frailty criteria: in-home and sensor-based gait (normal and fast walk), balance (bipedal eyes open and eyes closed), and spontaneous daily PA over 48 h, measured using validated wearable technologies. RESULTS: Of the 119 participants (36% non-frail, 48% pre-frail, and 16% frail), 48 reported one or more fall (47% of non-frail, 33% of pre-frail, and 47% of frail). Although balance deficit and PA were independent fall predictors in pre-frail and frail groups, they were not sensitive to predict prospective falls in the non-frail group. Even though gait performance deteriorated as frailty increased, gait was not a predictor of prospective falls when participants were stratified based on frailty status. In pre-frail and frail participants combined, center of mass sway [odds ratio (OR) = 5.9, 95% confidence interval (CI) 2.6-13.7], PA mean walking bout duration (OR = 1.1, 95% CI 1.0-1.2), PA mean standing bout duration (OR = 0.94, 95% CI 0.91-0.99), and a fall in previous 6 months (OR = 7.3, 95% CI 1.5-36.4) were independent predictors of prospective falls (area under the curve: 0.882). CONCLUSION: This study suggests that independent predictors of falls are dependent on frailty status. Among sensor-derived parameters, balance deficit, longer typical walking episodes, and shorter typical standing episodes were the most sensitive predictors of prospective falls in the combined pre-frail and frail sample. Gait deficit was not a sensitive fall predictor in the context of frailty status.

Postural Balance Parameters as Objective Surgical Assessments in Low Back Disorders: A Systematic Review.

Balance assessments could render useful objective performance measures to evaluate the efficacy of low back surgeries, yet these assessments have not been collectively examined to determine longitudinal sensitivity across surgical interventions. The purpose of this review was to determine sensitivity of balance measurements for disparate spinal disorders after surgical intervention. We searched PubMed, Embase, Scopus, the Cochrane Library, Web of Science, and CINAHL. Articles were selected based on: (1) sample consisted of low back disorder individuals and (2) balance measurements were obtained both pre- and postsurgery. Most of the articles addressed 2 specific low back disorders: (1) adolescent idiopathic scoliosis/spinal fusion and (2) disc herniation/decompression surgery. For scoliosis patients, body sway increased (14-97%) immediately following surgery but gradually reduced (1-33%) approaching the 1-year post spinal fusion assessment. For patients with disc herniation, sway range, sway velocity, sway area, and sway variability all decreased (19-42%) immediately postsurgery. Balance assessments for adolescents with idiopathic scoliosis who underwent surgical intervention should be performed with visual occlusion, focus on time domain parameters, and evaluated with longer follow-up times. Patients with disc herniation who underwent decompression surgery should have balance assessments with visual deprivation, test conditions specifically addressing hip strategy, and correlation with pain.

Influences of frailty syndrome on open-loop and closed-loop postural control strategy.

BACKGROUND: As the population of older adults quickly increases, the incidence of frailty syndrome, a reduction in physiological reserve across multiple physiological systems, likewise increases. To date, impaired balance has been associated with frailty; however, the underlying frailty-related postural balance mechanisms remain unclear. OBJECTIVE: The aim of the current study was to use open-loop (OL; postural muscles) and closed-loop (CL; postural muscles plus sensory feedback) mechanisms to explore differences in postural balance mechanisms between nonfrail (n = 44), prefrail (n = 59) and frail individuals (n = 19). METHODS: One hundred and twenty-two older adults (age ≥65 years) without major mobility disorders were recruited, and frailty was measured using Fried's criteria. Each participant performed two 15-second trials of Romberg balance assessment, once with their eyes open and once with their eyes closed. Body-worn sensors were used to estimate center of gravity (COG) plots. Body-sway (traditional stabilogram analysis) and OLCL (stabilogram diffusion analysis) parameters were derived using COG plots and compared between groups using ANOVA. Frailty and prefrailty were estimated using a multiple variable logistic regression while controlling for age, body mass index, body-sway and OLCL parameters. RESULTS: Between-group differences in the parameters of interest were more pronounced during the eyes-closed condition, for which OL duration was approximately 33 and 22% shorter, respectively, in the frail and prefrail groups when compared to nonfrail controls (mean = 1.9 ± 1.1 s, p = 0.01). The average rate of sway during the OL was 164 and 66% higher, respectively, in frail and prefrail when compared to nonfrail subjects (0.03 ± 0.02 cm(2)/s, p < 0.001). RESULTS also suggest that OLCL parameters can predict frail and prefrail categories when compared to nonfrail controls. Using this method, frailty was identified with a sensitivity and specificity of 97 and 88% (as compared to nonfrail), and prefrailty with 82 and 92%, respectively. CONCLUSIONS: This study suggested an innovative method to differentiate between frailty status using sensory dependency characteristics of postural control. RESULTS suggest that postural muscle deconditioning may compromise balance in frail elders, leading to dependency on somatosensory feedback to compensate for errors and stabilize the system.

Does integrative medicine enhance balance in aging adults? Proof of concept for the benefit of electroacupuncture therapy in Parkinson's disease.

BACKGROUND: Postural balance and potentially fall risk increases among older adults living with neurological diseases, especially Parkinson's disease (PD). Since conventional therapies such as levodopa or deep brain stimulation may fail to alleviate or may even worsen balance, interest is growing in evaluating alternative PD therapies. OBJECTIVE: The purpose of the current study was to assess improvement in postural balance in PD patients following electroacupuncture (EA) as an alternative therapy. METHODS: 15 aging adults (71.2 ± 6.3 years) with idiopathic PD and 44 healthy age-matched participants (74.6 ± 6.5 years) were recruited. The PD participants were randomly assigned (at a ratio of 2:1) to an intervention (n = 10) or to a control group (n = 5). The intervention group received a 30-min EA treatment on a weekly basis for 3 weeks, while the control group received a sham treatment. Outcomes were assessed at baseline and after the final therapy. Measurements included balance assessment, specifically the ratio of medial-lateral (ML) center-of-gravity (COG) sway to anterior-posterior (AP) sway (COGML/AP) and ankle/hip sway during eyes-open, eyes-closed, and eyes-open dual-task trials, the Unified Parkinson's Disease Rating Scale (UPDRS), as well as quality of life, concerns for fall, and pain questionnaires. RESULTS: No difference was observed for the assessed parameters between the intervention and the control group at baseline. After treatment, an improvement in balance performance was observed in the intervention group. Compared with the healthy population, PD patients prior to treatment had larger COGML/AP sway with more dependency on upper-body movements for maintaining balance. Following EA therapy, COGML/AP sway was reduced by 31% and ankle/hip sway increased by 46% in the different conditions (p = 0.02 for the dual-task condition). The clinical rating revealed an overall improvement (p < 0.01) in mentation, behavior, and mood (UPDRS part I, 49%), activities of daily living (UPDRS part II, 46%), and motor examination (UPDRS part III, 40%). There was a significant reduction (p < 0.02) in the specific items regarding UPDRS fall status (67%) and rigidity (48%). Changes were small and nonsignificant in the controls (p > 0.29). CONCLUSIONS: This pilot study demonstrates improvement in rigidity and balance following EA. These preliminary results suggest EA could be a promising alternative treatment for balance disturbance in PD.

Regulation of Cardiac Autonomic Nervous System Control across Frailty Statuses: A Systematic Review.

BACKGROUND: Frailty is a geriatric syndrome that leads to impairment in interrelated physiological systems and progressive homeostatic dysregulation in physiological systems. OBJECTIVE: The focus of the present systematic review was to study the association between the activity of the cardiac autonomic nervous system (ANS) and frailty. METHODS: A systematic literature search was conducted in multiple databases: PubMed/MEDLINE, Embase, Cochrane Library, Web of Science, CINAHL, and ClinicalTrials.gov; the last search was performed in March 2015. Inclusion criteria were: (1) that the studied population was classified for frailty according to a standard definition, such as Fried's criteria; (2) that the study had a nonfrail control group, and (3) that heart rate (HR) and/or heart rate variability (HRV) were parameters of interest in the study. RESULTS: Of the 1,544 articles screened, 54 were selected for full-text review and 6 studies met the inclusion criteria. Assessment of HRV using different standard time domain, frequency domain, and nonlinear domain approaches confirmed the presence of an impaired cardiac ANS function in frail compared to nonfrail participants. Furthermore, HR changes while performing a clinical test (e.g., the seated step test or the lying-to-standing orthostatic test) were decreased in the frail group compared to the nonfrail group. CONCLUSIONS: The current systematic review provides evidence that the cardiac ANS is impaired in frail compared to nonfrail older adults, as indicated by a reduction in the complexity of HR dynamics, reduced HRV, and reduced HR changes in response to daily activities. Four out of 6 included articles recruited only female participants, and in the other 2 articles the effect of gender on impairment of cardiac ANS was insufficiently investigated. Therefore, further studies are required to study the association between cardiac ANS impairments and frailty in males. Furthermore, HRV was studied only during static postures such as sitting, or without considering the level of activity as a potential confounder. Accordingly, simultaneous measurement of both physiological (i.e., HRV) and kinematic (e.g., using wearable sensor technology) information may provide a better understanding of cardiac ANS impairments with frailty while controlling for activity.

Motorized mobility scooters: the use of training/intervention and technology for improving driving skills in aging adults - a mini-review.

BACKGROUND: Motorized mobility scooters (MMS) have become the most acceptable powered assistive device for those with impaired mobility, who have sufficient upper body strength and dexterity, and postural stability. Although several benefits have been attributed to MMS usage, there are likewise risks of use, including injuries and even deaths. OBJECTIVE: The aim of the current review was to summarize results from clinical studies regarding the enhancement of MMS driver safety with a primary focus on improving driving skills/performance using clinical approaches. We addressed three main objectives: (1) to identify and summarize any available evidence (strong, moderate, or weak evidence based on the quality of studies) regarding improved driving skills/performance following training/intervention; (2) to identify types of driving skills/performance that might be improved by training/intervention, and (3) to identify the use of technology in improving MMS performance or training procedure. METHODS: Articles were searched for in the following medical and engineering electronic databases: PubMed, Cochrane Library, Web of Science, ClinicalTrials.gov, PsycINFO, CINAHL, ERIC, EI Compendix, IEEE Explore, and REHABDATA. Inclusion criteria included: aging adults or those with ambulatory problems, intervention or targeted training, and clinical trial. Outcomes included: MMS skills/performance. RESULTS: Six articles met the inclusion criteria and are analyzed in this review. Four of the six articles contained training approaches for MMS drivers including skill trainings using real MMS inside and outside (i.e. in the community) and in a 3D virtual environment. The other two studies contain infrastructural assessments (i.e. the minimum space required for safe maneuverability of MMS users) and additional mobility assistance tools to improve maneuverability and to enhance driving performance. CONCLUSIONS: RESULTS from the current review showed improved driving skills/performance by training, infrastructural assessments, and incorporating mobility assistance tools. MMS driving skills that can be improved through driver training include: weaving, negotiating with and avoiding pedestrian interference, simultaneous reading of signs and obstacle avoidance in path, level driving, forward and reverse driving, figure 8s, turning in place, crossing left slope, maneuvering down a 2-inch curb, and driving up and down inclines. However, several limitations exist in the available literature regarding evidence of improved driving skills/performance following training/intervention, such as small sample sizes, lack of control groups and statistical analysis.

Associating frailty and dynamic dysregulation between motor and cardiac autonomic systems.

Frailty is a geriatric syndrome associated with the lack of physiological reserve and consequent adverse outcomes (therapy complications and death) in older adults. Recent research has shown associations between heart rate (HR) dynamics (HR changes during physical activity) with frailty. The goal of the present study was to determine the effect of frailty on the interconnection between motor and cardiac systems during a localized upper-extremity function (UEF) test. Fifty-six individuals aged 65 or above were recruited and performed the previously developed UEF test consisting of 20-s rapid elbow flexion with the right arm. Frailty was assessed using the Fried phenotype. Wearable gyroscopes and electrocardiography were used to measure motor function and HR dynamics. In this study, the interconnection between motor (angular displacement) and cardiac (HR) performance was assessed, using convergent cross-mapping (CCM). A significantly weaker interconnection was observed among pre-frail and frail participants compared to non-frail individuals (p < 0.01, effect size = 0.81 ± 0.08). Using logistic models, pre-frailty and frailty were identified with sensitivity and specificity of 82%-89%, using motor, HR dynamics, and interconnection parameters. Findings suggested a strong association between cardiac-motor interconnection and frailty. Adding CCM parameters in a multimodal model may provide a promising measure of frailty.