Precious Metal Free Hydrogen Evolution Catalyst Design and Application.

The quest to identify precious metal free hydrogen evolution reaction catalysts has received unprecedented attention in the past decade. In this Review, we focus our attention to recent developments in precious metal free hydrogen evolution reactions in acidic and alkaline electrolyte owing to their relevance to commercial and near-commercial low-temperature electrolyzers. We provide a detailed review and critical analysis of catalyst activity and stability performance measurements and metrics commonly deployed in the literature, as well as review best practices for experimental measurements (both in half-cell three-electrode configurations and in two-electrode device testing). In particular, we discuss the transition from laboratory-scale hydrogen evolution reaction (HER) catalyst measurements to those in single cells, which is a critical aspect crucial for scaling up from laboratory to industrial settings but often overlooked. Furthermore, we review the numerous catalyst design strategies deployed across the precious metal free HER literature. Subsequently, we showcase some of the most commonly investigated families of precious metal free HER catalysts; molybdenum disulfide-based, transition metal phosphides, and transition metal carbides for acidic electrolyte; nickel molybdenum and transition metal phosphides for alkaline. This includes a comprehensive analysis comparing the HER activity between several families of materials highlighting the recent stagnation with regards to enhancing the intrinsic activity of precious metal free hydrogen evolution reaction catalysts. Finally, we summarize future directions and provide recommendations for the field in this area of electrocatalysis.

Prefrontal Cortex Activity During Gait in People With Persistent Symptoms After Concussion.

BACKGROUND: Concussions result in transient symptoms stemming from a cortical metabolic energy crisis. Though this metabolic energy crisis typically resolves in a month, symptoms can persist for years. The symptomatic period is associated with gait dysfunction, the cortical underpinnings of which are poorly understood. Quantifying prefrontal cortex (PFC) activity during gait may provide insight into post-concussion gait dysfunction. The purpose of this study was to explore the effects of persisting concussion symptoms on PFC activity during gait. We hypothesized that adults with persisting concussion symptoms would have greater PFC activity during gait than controls. Within the concussed group, we hypothesized that worse symptoms would relate to increased PFC activity during gait, and that increased PFC activity would relate to worse gait characteristics. METHODS: The Neurobehavior Symptom Inventory (NSI) characterized concussion symptoms. Functional near-infrared spectroscopy quantified PFC activity (relative concentration changes of oxygenated hemoglobin [HbO2]) in 14 people with a concussion and 25 controls. Gait was assessed using six inertial sensors in the concussion group. RESULTS: Average NSI total score was 26.4 (13.2). HbO2 was significantly higher (P = .007) for the concussed group (0.058 [0.108]) compared to the control group (-0.016 [0.057]). Within the concussion group, HbO2 correlated with NSI total symptom score (ρ = .62; P = .02), sagittal range of motion (r = .79; P = .001), and stride time variability (r = -.54; P = .046). CONCLUSION: These data suggest PFC activity relates to symptom severity and some gait characteristics in people with persistent concussion symptoms. Identifying the neurophysiological underpinnings to gait deficits post-concussion expands our knowledge of motor behavior deficits in people with persistent concussion symptoms.

Turning speed as a more responsive metric of age-related decline in mobility: A comparative study with gait speed.

BACKGROUND: Navigating your environment requires both straight-line gait as well as turning. Gait speed normative values are well established and utilized in determining a person's functional status, however, it has limitations. This study sought to examine whether turning speed declines with age and how it compared to gait speed age-related decline. METHODS: A secondary analysis was performed on 275 community dwelling adults between the ages of 18-88 that performed a timed walking test with an inertial measurement unit on their lumbar spine. Turning speed and walking speed were extracted for each participant. A series of mixed models were compared, and Akaike's Information Criterion was used to determine the best fit model between age and turning speed and age and gait speed. FINDINGS: Turning speed and gait speed normative values were reported for each age decade. A linear model with a random intercept of "Condition" was used to assess the relationship between age and turning speed. The results indicated a significant negative relationship between age and turning speed (B = -0.66, p < 0.001). A spline-fit model determined a significant negative relationship between age and gait speed after the age of 65 (B = -0.0097, p = 0.002). The effect of age on gait speed before age 65 was not significant. INTERPRETATION: Turning speed significantly declines with age in a linear fashion while gait speed begins to decline after age 65. Turning speed may be more responsive to age than gait speed. More research is needed to determine if the decline in turning speed with age is associated with a decline in function.

Reconsidering Vestibular/Ocular Motor Screening Cutoff Scores for Concussion.

INTRODUCTION: Vestibular/Ocular Motor Screening (VOMS) is often part of a comprehensive evaluation to identify acute mild traumatic brain injury. Most of the reports describe the use of the VOMS in adolescents/young adults and not in older adults or military service members. The purpose of this study was to describe VOMS findings in healthy civilians and active duty military service members up to the age of 50 years. MATERIALS AND METHODS: Seventy-seven healthy civilians between 18 and 50 years of age (22 males, age 31.8 [9.0] years) participated across three sites in addition to 40 healthy active duty service members (25 males, age 27.5 [4.9] years) from one site. Demographics, Neurobehavioral Symptom Inventory scores, mean near point convergence (NPC) distance, and Total Symptom Change (TSS) scores from the VOMS were evaluated. RESULTS: For civilians, the group mean NPC distance was 4.98 (3.8) cm. For military service members, the group mean NPC distance was 6.17 (4.57) cm. For civilians, the mean TSS was 1.2 (2.3) with 53.2% reporting 0 TSS, 27.3% reporting one TSS, and 19.5% reporting two or more TSS. For military service members, the mean TSS was 0.20 (0.72) with 92.5% reporting 0 TSS, 0% reporting one TSS, and 7.5% reporting two or more TSS. Age did not correlate with the mean NPC distance and TSS in healthy civilians and active duty military service members. CONCLUSIONS: Reconsideration of the Military Acute Concussion Evaluation, Version 2 cutoff value for abnormal mean NPC distance may be warranted to improve diagnostic accuracy in both civilian and military adult populations. Similarly, re-evaluating criteria for interpreting the TSS results of the VOMS, specifically in civilians, may be warranted.

Quantifying Turning Tasks With Wearable Sensors: A Reliability Assessment.

OBJECTIVE: The aim of this study was to establish the test-retest reliability of metrics obtained from wearable inertial sensors that reflect turning performance during tasks designed to imitate various turns in daily activity. METHODS: Seventy-one adults who were healthy completed 3 turning tasks: a 1-minute walk along a 6-m walkway, a modified Illinois Agility Test (mIAT), and a complex turning course (CTC). Peak axial turning and rotational velocity (yaw angular velocity) were extracted from wearable inertial sensors on the head, trunk, and lumbar spine. Intraclass correlation coefficients (ICCs) were established to assess the test-retest reliability of average peak turning speed for each task. Lap time was collected for reliability analysis as well. RESULTS: Turning speed across all tasks demonstrated good to excellent reliability, with the highest reliability noted for the CTC (45-degree turns: ICC = 0.73-0.81; 90-degree turns: ICC = 0.71-0.83; and 135-degree turns: ICC = 0.72-0.80). The reliability of turning speed during 180-degree turns from the 1-minute walk was consistent across all body segments (ICC = 0.74-0.76). mIAT reliability ranged from fair to excellent (end turns: ICC = 0.52-0.72; mid turns: ICC = 0.50-0.56; and slalom turns: ICC = 0.66-0.84). The CTC average lap time demonstrated good test-retest reliability (ICC = 0.69), and the mIAT average lap time test-retest reliability was excellent (ICC = 0.91). CONCLUSION: Turning speed measured by inertial sensors is a reliable outcome across a variety of ecologically valid turning tasks that can be easily tested in a clinical environment. IMPACT: Turning performance is a reliable and important measure that should be included in clinical assessments and clinical trials.

Exercise Intolerance After Mild Traumatic Brain Injury Occurs in All Subtypes in the Adult Population.

Thematically grouped symptom clusters are present during the acute timeline of post-mild traumatic brain injuries (mTBI), representing clinical profiles called subtypes. Exercise intolerance has not been evaluated within the subtype classifications and, because guidelines support early submaximal aerobic exercise, further knowledge is required in regard to the exercise capabilities among the concussion subtypes. This cross-sectional study (n = 78) aimed to characterize the presence of exercise intolerance within the clinical subtypes and to explore performance on the Buffalo Concussion Treadmill Test (BCTT) in the adult subacute (2-12 weeks post-injury) mTBI population. All participants were evaluated using the BCTT to determine exercise tolerance. We first used the Neurobehavioral Symptom Inventory (NSI) questionnaire to assign each participant a primary subtype(s). To further explore all five subtypes (headache, cognitive, vestibular, ocular motor, and mood), participants were assessed using a multitude of thematically grouped assessments including self-reported questionnaires, clinical tests of vestibular and ocular motor function, balance function, and computerized cognitive testing. Thirty-seven (47%) subjects were exercise tolerant and 41 (53%) were exercise intolerant. There was no difference in the distribution of primary subtypes between the exercise tolerant and exercise intolerant groups. In addition, no significant differences were found between the exercise tolerant and exercise intolerant groups on other thematically grouped subtype assessments. The exercise intolerant group had a significantly higher resting heart rate (HR), lower percentage of age-predicted maximum HR achieved, lower Borg Rate of Perceived Exertion (RPE), and could walk on the treadmill for less time (lower duration) compared with the exercise tolerant group. The current findings suggest that exercise intolerance is common and pervasive across all five mTBI subtypes. A comprehensive mTBI assessment should include evaluation for exercise intolerance regardless of the primary clustering of symptoms and across patient populations. Therefore, early referral to physical therapists, athletic trainers, or medical clinics that can perform the BCTT may be helpful to initiate appropriate exercise prescriptions for patients with mTBI.

Assessing the Effects of Mild Traumatic Brain Injury on Vestibular Home Exercise Performance with Wearable Sensors.

After a mild traumatic brain injury (mTBI), dizziness and balance problems are frequently reported, affecting individuals' daily lives and functioning. Vestibular rehabilitation is a standard treatment approach for addressing these issues, but its efficacy in this population remains inconclusive. A potential reason for suboptimal outcomes is the lack of objective monitoring of exercise performance, which is crucial for therapeutic success. This study utilized wearable inertial measurement units (IMUs) to quantify exercise performance in individuals with mTBI during home-based vestibular rehabilitation exercises. Seventy-three people with mTBI and fifty healthy controls were enrolled. Vestibular exercises were performed, and IMUs measured forehead and sternum velocities and range of motions. The mTBI group demonstrated a slower forehead peak angular velocity in all exercises, which may be a compensatory strategy to manage balance issues or symptom exacerbation. Additionally, the mTBI group exhibited a larger forehead range of motion during specific exercises, potentially linked to proprioceptive deficits. These findings emphasize the usefulness of utilizing IMUs to monitor the quality of home-based vestibular exercises for individuals with mTBI and the potential for IMUs improving rehabilitation outcomes.

Relation Between Cognitive Assessment and Clinical Physical Performance Measures After Mild Traumatic Brain Injury.

OBJECTIVES: To investigate the relation between cognitive and motor performance in individuals with mild traumatic brain injury (mTBI) and examine differences in both cognitive and motor performance between adults after mTBI and healthy controls. DESIGN: Multi-center, cross-sectional study. SETTING: Three institutional sites (Courage Kenny Research Center, Minneapolis, MN, Oregon Health & Science University, Portland, OR, and University of Utah, Salt Lake City, UT). PARTICIPANTS: Data were collected from 110 participants (N=110), including those with mTBI and healthy controls, who completed cognitive and physical performance assessments. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Cognitive assessments involved the Automated Neuropsychological Assessment Metrics to evaluate domains of attention, memory, reaction time, processing speed, and executive function. Physical performance was evaluated through clinical performance assessments, such as the 1-min walk test, the modified Illinois Agility Test, the Functional Gait Assessment Tool, the High-Level Mobility Assessment Tool, a complex turning course, and a 4-Item Hybrid Assessment of Mobility for mTBI. Participants also completed additional trials of the 1-min walk test, modified Illinois Agility Test, and complex turning course with a simultaneous cognitive task. RESULTS: Individuals with mTBI performed worse on cognitive assessments, as well as several of the physical performance assessments compared with healthy controls. Complex tasks were more strongly related to cognitive assessments compared with simple walking tasks. CONCLUSIONS: Combining complex motor tasks with cognitive demands may better demonstrate functional performance in individuals recovering from mTBI. By understanding the relation between cognitive and physical performance in individuals recovering from mTBI, clinicians may be able to improve clinical care and assist in return to activity decision-making.

Balance telerehabilitation and wearable technology for people with Parkinson's disease (TelePD trial).

BACKGROUND: Balance impairments, that lead to falls, are one of the main symptoms of Parkinson's disease (PD). Telerehabilitation is becoming more common for people with PD; however, balance is particularly challenging to assess and treat virtually. The feasibility and efficacy of virtual assessment and virtual treatment of balance in people with PD are unknown. The present study protocol has three aims: I) to determine if a virtual balance and gait assessment (instrumented L-shape mobility test) with wearable sensors can predict a gold-standard, in-person clinical assessment of balance, the Mini Balance Evaluation Systems Test (Mini-BESTest); II) to explore the effects of 12 sessions of balance telerehabilitation and unsupervised home exercises on balance, gait, executive function, and clinical scales; and III) to explore if improvements after balance telerehabilitation transfer to daily-life mobility, as measured by instrumented socks with inertial sensors worn for 7 days. METHODS: The TelePD Trial is a prospective, single-center, parallel-group, single-blind, pilot, randomized, controlled trial. This trial will enroll 80 eligible people with PD. Participants will be randomized at a 1:1 ratio into receiving home-based balance exercises in either: 1) balance telerehabilitation (experimental group, n = 40) or 2) unsupervised exercises (control group, n = 40). Both groups will perform 12 sessions of exercise at home that are 60 min long. The primary outcome will be Mini-BESTest. The secondary outcomes will be upper and lower body gait metrics from a prescribed task (instrumented L-shape mobility test); daily-life mobility measures over 7 days with wearable sensors in socks, instrumented executive function tests, and clinical scales. Baseline testing and 7 days of daily-life mobility measurement will occur before and after the intervention period. CONCLUSION: The TelePD Trial will be the first to explore the usefulness of using wearable sensor-based measures of balance and gait remotely to assess balance, the feasibility and efficacy of balance telerehabilitation in people with PD, and the translation of balance improvements after telerehabilitation to daily-life mobility. These results will help to develop a more effective home-based balance telerehabilitation and virtual assessment that can be used remotely in people with balance impairments. TRIAL REGISTRATION: This trial was prospectively registered on ClinicalTrials.gov (NCT05680597).

Exploring mobility dysfunction in people with and without impaired cognition in Parkinson disease.

INTRODUCTION: The relationship between mobility and cognition has been studied in the aging population and associations have been also reported in people with Parkinson's disease (PD). OBJECTIVE: To compare different aspects of gait and balance between individuals with PD who have normal cognition and those with impaired cognition, using both clinical and instrumented measures. METHODS: One-hundred forty-three participants with PD were divided into two groups: 1) normal cognition (n = 71) and 2) impaired cognition (n = 72) based on the Montreal Cognitive Assessment (MoCA) cut-off. Groups were compared using instrumented and clinical measures of gait and balance in the following domains: Sensory Orientation, Anticipatory Postural Adjustments, Automatic Postural Responses and Dynamic Balance for Gait. Instrumented measures were obtained via wearable sensors while performing eight different motor tasks and clinical measures were obtained with the Mini-BESTest. RESULTS: The total Mini-BESTest score was not different between groups. However, the Dynamic Gait domain was worse in individuals with impaired cognition. Among the instrumented measures across domains, all significant group differences were in the Dynamic Gait domain, specifically, dual-task gait speed, dual-task stride length, stance time, and turn velocity. CONCLUSIONS: Dynamic balance during gait was more impaired in people with PD who had abnormal cognition than those with normal cognition, for both clinical and instrumented measures. All other balance domains did not differ between groups, for both instrumented and clinical measures.

Volitional Head Movement Deficits and Alterations in Gait Speed Following Mild Traumatic Brain Injury.

OBJECTIVE: Unconstrained head motion is necessary to scan for visual cues during navigation, for minimizing threats, and to allow regulation of balance. Following mild traumatic brain injury (mTBI) people may experience alterations in head movement kinematics, which may be pronounced during gait tasks. Gait speed may also be impacted by the need to turn the head while walking in these individuals. The aim of this study was to examine head kinematics during dynamic gait tasks and the interaction between kinematics and gait speed in people with persistent symptoms after mTBI. SETTING: A clinical assessment laboratory. DESIGN: A cross-sectional, matched-cohort study. PARTICIPANTS: Forty-five individuals with a history of mTBI and 46 age-matched control individuals. MAIN MEASURES: All participants were tested at a single time point and completed the Functional Gait Assessment (FGA) while wearing a suite of body-mounted inertial measurement units (IMUs). Data collected from the IMUs were gait speed, and peak head rotation speed and amplitude in the yaw and pitch planes during the FGA-1, -3, and -4 tasks. RESULTS: Participants with mTBI demonstrated significantly slower head rotations in the yaw ( P = .0008) and pitch ( P = .002) planes. They also demonstrated significantly reduced amplitude of yaw plane head rotations ( P < .0001), but not pitch plane head rotations ( P = .84). Participants with mTBI had significantly slower gait speed during normal gait (FGA-1) ( P < .001) and experienced a significantly greater percent decrease in gait speed than healthy controls when walking with yaw plane head rotations (FGA-3) ( P = .02), but not pitch plane head rotations (FGA-4) ( P = .11). CONCLUSIONS: Participants with mTBI demonstrated smaller amplitudes and slower speeds of yaw plane head rotations and slower speeds of pitch plane head rotations during gait. Additionally, people with mTBI walked slower during normal gait and demonstrated a greater reduction in gait speed while walking with yaw plane head rotations compared with healthy controls.

A Hybrid Assessment of Clinical Mobility Test Items for Evaluating Individuals With Mild Traumatic Brain Injury.

BACKGROUND AND PURPOSE: The Functional Gait Assessment (FGA) and High Level Mobility Assessment Tool (HiMAT) are clinical batteries used to assess people with mild traumatic brain injury (mTBI). However, neither assessment was specifically developed for people with mTBI; the FGA was developed to evaluate vestibular deficits, and the HiMAT was developed for individuals with more severe TBI. To maximize the sensitivity and reduce the time burden of these assessments, the purpose of this study was to determine the combination of FGA and HiMAT items that best discriminates persons with persistent symptoms from mTBI from healthy controls. METHODS: Fifty-three symptomatic civilians with persistent symptoms from mTBI (21% male, aged 31 (9.5) years, 328 [267] days since concussion) and 57 healthy adults (28% male, aged 32 (9.6) years) participated across 3 sites. The FGA and HiMAT were evaluated sequentially as part of a larger study. To determine the best combination of items, a lasso-based generalized linear model (glm) was fit to all data. RESULTS: The area under the curve (AUC) for FGA and HiMAT total scores was 0.68 and 0.66, respectively. Lasso regression selected 4 items, including FGA Gait with Horizontal Head Turns and with Pivot Turn, and HiMAT Fast Forward and Backward Walk, and yielded an AUC (95% confidence interval) of 0.71 (0.61-0.79) using standard scoring. DISCUSSION AND CONCLUSIONS: The results provide initial evidence supporting a reduced, 4-Item Hybrid Assessment of Mobility for mTBI (HAM-4-mTBI) for monitoring individuals with mTBI. Future work should validate the HAM-4-mTBI and investigate its utility for tracking progression throughout rehabilitation.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A409 ).

Assessment of balance in people with mild traumatic brain injury using a balance systems model approach.

PURPOSE: Measuring persistent imbalance after mTBI is challenging and may include subjective symptom-reporting as well as clinical scales. Clinical assessments for quantifying balance following mTBI have focused on sensory orientation. It is theorized that balance control goes beyond sensory orientation and also includes subdomains of anticipatory postural adjustments, reactive postural control, and dynamic gait. The Mini Balance Evaluation Systems Test (Mini-BESTest) is a validated balance test that measures balance according to these subdomains for a more comprehensive assessment. The purpose of this study was to compare Mini-BESTest total and subdomain scores after subacute mTBI with healthy controls. METHODS: Symptomatic mTBI (n = 90, 20 % male, age=36.0 ± 12.0, 46.3.4 ± 22.1 days since injury) and healthy control (n = 45, 20 % male, age=35.4 ± 12.5) participants completed the Mini-BESTest for balance. Mini-BESTest between-group differences were evaluated using Wilcoxon rank-sum tests. RESULTS: The mTBI group (Median[minimum,maximum]) had a significantly worse Mini-BESTest total score than the healthy controls (24[18,28] vs 27[23-28], p < 0.001). The mTBI group performed significantly worse in 3 of the 4 subdomains compared to the healthy controls: reactive postural control: 5[2-6] vs 6[3-6], p = 0.003; sensory orientation: 6[5,6] vs 6[6], p = 0.005; dynamic gait: 8[5-10] vs 9[8-10], p < 0.001. There was no significance difference between groups in the anticipatory postural adjustments domain (5[3-6] vs 5[3-6], p = 0.12). CONCLUSIONS: The Mini-BESTest identified deficits in people with subacute mTBI in the total score and 3 out of 4 subdomains, suggesting it may be helpful to use in the clinic to identify balance subdomain deficits in the subacute mTBI population. In combination with self-reported assessments, the mini-BESTest may identify balance domain deficits in the subacute mTBI population and help guide treatment for this population.

Symptoms and Central Sensory Integration in People With Chronic mTBI: Clinical Implications.

INTRODUCTION: Balance deficits in people with chronic mild traumatic brain injury (mTBI; ≥3 months post-mTBI), thought to relate to central sensory integration deficits, are subtle and often difficult to detect. The purpose of this study was to determine the sensitivity of the instrumented modified clinical test of sensory integration for balance (mCTSIB) in identifying such balance deficits in people with symptomatic, chronic mTBI and to establish the associations between balance and mTBI symptom scores in the chronic mTBI group. METHODS: The Institutional Review Board approved these study methods. Forty-one people with chronic mTBI and balance complaints and 53 healthy controls performed the mCTSIB (eyes open/closed on firm/foam surfaces; EoFi, EcFi, EoFo, and EcFo) with a wearable sensor on their waist to quantify sway area (m2/s4). Sensory reweighting variables were calculated for the firm and foam stance conditions. A stopwatch provided the clinical outcome for the mCTSIB (time). Each participant completed the Neurobehavioral Symptom Inventory (NSI), which quantifies mTBI-related symptoms and provides a total score, as well as sub-scores on affective, cognitive, somatic, and vestibular domains. RESULTS: The mTBI group reported significantly higher symptom scores across each NSI sub-score (all Ps < .001). The mTBI group had a significantly larger sway area than the control group across all mCTSIB conditions and the mTBI group had significantly higher sensory reweighting scores compared to the control group on both the firm (P = .01) and foam (P = .04) surfaces. Within the mTBI group, the NSI vestibular score significantly related to the mCTSIB sway area EcFi (r = 0.38; P = .02), sway area EcFo (r = 0.43; P = .006), sensory reweighting firm (r = 0.33; P = .04), and sensory reweighting foam (r = 0.38; P = .02). The average sway area across the 4 mCTSIB conditions was significantly (area under the curve: 0.77; P < .001) better at differentiating groups than the mCTSIB clinical total score. The average sway area across the 4 mCTSIB conditions had a sensitivity of 73% and a specificity of 71%. The clinical mCTSIB outcome scores were not different between groups. CONCLUSION: People with chronic mTBI appear to have central sensory integration deficits detectable by instrumented measures of postural assessment. These findings suggest that central sensory integration should be targeted in rehabilitation for people with chronic mTBI.

Central sensorimotor integration assessment reveals deficits in standing balance control in people with chronic mild traumatic brain injury.

Imbalance is common following mild Traumatic Brain Injury (mTBI) and can persist months after the initial injury. To determine if mTBI subjects with chronic imbalance differed from healthy age- and sex-matched controls (HCs) we used both the Central SensoriMotor Integration (CSMI) test, which evaluates sensory integration, time delay, and motor activation properties and the standard Sensory Organization Test (SOT). Four CSMI conditions evoked center-of-mass sway in response to: surface tilts with eyes closed (SS/EC), surface tilts with eyes open viewing a fixed visual surround (SS/EO), visual surround tilts with eyes open standing on a fixed surface (VS/EO), and combined surface and visual tilts with eyes open (SS+VS/EO). The mTBI participants relied significantly more on visual cues during the VS/EO condition compared to HCs but had similar reliance on combinations of vestibular, visual, and proprioceptive cues for balance during SS/EC, SS/EO, and SS+VS/EO conditions. The mTBI participants had significantly longer time delays across all conditions and significantly decreased motor activation relative to HCs across conditions that included surface-tilt stimuli with a sizeable subgroup having a prominent increase in time delay coupled with reduced motor activation while demonstrating no vestibular sensory weighting deficits. Decreased motor activation compensates for increased time delay to maintain stability of the balance system but has the adverse consequence that sensitivity to both internal (e.g., sensory noise) and external disturbances is increased. Consistent with this increased sensitivity, SOT results for mTBI subjects showed increased sway across all SOT conditions relative to HCs with about 45% of mTBI subjects classified as having an "Aphysiologic" pattern based on published criteria. Thus, CSMI results provided a plausible physiological explanation for the aphysiologic SOT pattern. Overall results suggest that rehabilitation that focuses solely on sensory systems may be incomplete and may benefit from therapy aimed at enhancing rapid and vigorous responses to balance perturbations.

The effects of augmenting traditional rehabilitation with audio biofeedback in people with persistent imbalance following mild traumatic brain injury.

Complaints of non-resolving imbalance are common in individuals with chronic mild traumatic brain injury (mTBI). Vestibular rehabilitation therapy may be beneficial for this population. Additionally, wearable sensors can enable biofeedback, specifically audio biofeedback (ABF), and aid in retraining balance control mechanisms in people with balance impairments. In this study, we described the effectiveness of vestibular rehabilitation therapy with and without ABF to improve balance in people with chronic mTBI. Participants (n = 31; females = 22; mean age = 40.9 ± 11 y) with chronic (>3 months) mTBI symptoms of self-reported imbalance were randomized into vestibular rehabilitation with ABF (n = 16) or without ABF (n = 15). The intervention was a standard vestibular rehabilitation, with or without ABF, for 45 min biweekly for 6 weeks. The ABF intervention involved a smartphone that provided auditory feedback when postural sway was outside of predetermined equilibrium parameters. Participant's completed the Post-Concussion Symptom Scale (PCSS). Balance was assessed with the sensory organization test (SOT) and the Central Sensorimotor Integration test which measured sensory weighting, motor activation, and time delay with sway evoked by surface and/or visual surround tilts. Effect sizes (Hedge's G) were calculated on the change between pre-and post-rehabilitation scores. Both groups demonstrated similar medium effect-sized decreases in PCSS and large increases in SOT composite scores after rehabilitation. Effect sizes were minimal for increasing sensory weighting for both groups. The with ABF group showed a trend of larger effect sizes in increasing motor activation (with ABF = 0.75, without ABF = 0.22) and in decreasing time delay (with ABF = -0.77, without ABF = -0.52) relative to the without ABF group. Current clinical practice focuses primarily on sensory weighting. However, the evaluation and utilization of motor activation factors in vestibular rehabilitation, potentially with ABF, may provide a more complete assessment of recovery and improve outcomes.

Effects of a Cognitively Challenging Agility Boot Camp Program on Balance and Gait in People With Parkinson's Disease: Does Freezing of Gait Status Matter?

BACKGROUND AND AIM: Individuals with Parkinson's disease (PD) with and without freezing of Gait (FoG) may respond differently to exercise interventions for several reasons, including disease duration. This study aimed to determine whether both people with and without FoG benefit from the Agility Boot Camp with Cognitive Challenges (ABC-C) program. METHODS: This secondary analysis of our ABC-C trial included 86 PD subjects: 44 without FoG (PD-FoG) and 42 with FoG (PD + FoG). We collected measures of standing sway balance, anticipatory postural adjustments, postural responses, and a 2-minute walk with and without a cognitive task. Two-way repeated analysis of variance, with disease duration as covariate, was used to investigate the effects of ABC-C program. Effect sizes were calculated using standardized response mean (SRM) for PD-FoG and PD + FoG, separately. RESULTS: The ABC-C program was effective in improving gait performance in both PD-FoG and PD + FoG, even after controlling for disease duration. Specifically, dual-task gait speed (P < .0001), dual-cost stride length (P = .012), and these single-task measures: arm range of motion (P < .0001), toe-off angle (P = .005), gait cycle duration variability (P = .019), trunk coronal range of motion (P = .042), and stance time (P = .046) improved in both PD-FoG and PD + FoG. There was no interaction effect between time (before and after exercise) and group (PD-FoG/PD + FoG) in all 24 objective measures of balance and gait. Dual-task gait speed improved the most in PD + FoG (SRM = 1.01), whereas single-task arm range of motion improved the most in PD-FoG (SRM = 1.01). CONCLUSION: The ABC-C program was similarly effective in improving gait (and not balance) performance in both PD-FoG and PD + FoG.

Exploring Age and Sex Patterns for Rehabilitation Referrals After a Concussion: A Retrospective Analysis.

Objective: To explore patterns of postconcussion care at a level 1 trauma center. Design: Retrospective cohort study. Setting: U.S. level 1 trauma center and local satellite units. Participants: Patients of any age with a concussion diagnosis that reported to level 1 trauma center and local satellite units between 2016 and 2018 (N=2417). Intervention: Not applicable. Main Outcome Measures: Age, sex, point of entry, rehabilitation referrals, and pre-existing comorbidity diagnosis. Results: Patient age (mean [SD]) significantly differed among points of entry, from youngest to oldest: 26.0 (14.0) years in sports medicine, 29.3 (23.0) years in the emergency department, 34.6 (23.6) years at primary care providers, and 46.0 (19.7) years at specialty care departments. Sex also significantly differed among points of entry; emergency departments reported more men (55.6%), whereas the other points of entry reported more women (59.3%-65.6%). Patients were more likely to receive a referral from sports medicine (odds ratio [OR]unadjusted=75.05, P<.001), primary care providers (ORunadjusted=7.98, P<.001), and specialty care departments (ORunadjusted=7.62, P<.001) than from the emergency department. Women were more likely to receive a referral (ORunadjusted=1.92, P<.0001), regardless of point of entry. Lastly, patients with a preexisting comorbidity were more likely (ORadjusted=2.12, P<.001) to get a rehabilitation referral than patients without a comorbidity. Conclusions: Point of entry, age, sex, and preexisting comorbidities are associated with postconcussion care rehabilitation referral patterns. Improving concussion education dissemination across all entry points of a level 1 trauma center may standardize the postconcussion rehabilitation referral patterns, potentially improving the time to recovery from a concussion.

Implementation and Adoption of Telerehabilitation for Treating Mild Traumatic Brain Injury.

BACKGROUND AND PURPOSE: Multimodal physical therapy for mild traumatic brain injury (mTBI) has been shown to improve recovery. Due to the coronavirus disease-2019 (COVID-19) pandemic, a clinical trial assessing the timing of multimodal intervention was adapted for telerehabilitation. This pilot study explored feasibility and adoption of an in-person rehabilitation program for subacute mTBI delivered through telerehabilitation. METHODS: Fifty-six in-person participants-9 males; mean (SD) age 34.3 (12.2); 67 (31) days post-injury-and 17 telerehabilitation participants-8 males; age 38.3 (12.7); 61 (37) days post-injury-with subacute mTBI (between 2 and 12 weeks from injury) were enrolled. Intervention included 8, 60-minute visits over 6 weeks and included subcategories that targeted cervical spine, cardiovascular, static balance, and dynamic balance impairments. Telerehabilitation was modified to be safely performed at home with minimal equipment. Outcome measures included feasibility (the number that withdrew from the study, session attendance, home exercise program adherence, adverse events, telerehabilitation satisfaction, and progression of exercises performed), and changes in mTBI symptoms pre- and post-rehabilitation were estimated with Hedges' g effect sizes. RESULTS: In-person and telerehabilitation had a similar study withdrawal rate (13% vs 12%), high session attendance (92% vs 97%), and no adverse events. The telerehabilitation group found the program easy to use (4.2/5), were satisfied with care (4.7/5), and thought it helped recovery (4.7/5). The telerehabilitation intervention was adapted by removing manual therapy and cardiovascular portions and decreasing dynamic balance exercises compared with the in-person group. The in-person group had a large effect size (-0.94) in decreases in symptoms following rehabilitation, while the telerehabilitation group had a moderate effect size (-0.73). DISCUSSION AND CONCLUSIONS: Telerehabilitation may be feasible for subacute mTBI. Limited ability to address cervical spine, cardiovascular, and dynamic balance domains along with underdosage of exercise progression may explain group differences in symptom resolution.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A392 ).

Do sensorimotor control properties mediate sway in people with chronic balance complaints following mTBI?

BACKGROUND: Up to 40% of mild traumatic brain injuries (mTBI) can result in chronic unresolved symptoms, such as balance impairment, that persist beyond three months. Sensorimotor control, the collective coordination and regulation of both sensory and motor components of the postural control system, may underlie balance deficits in chronic mTBI. The aim of this study was to determine if the relationship between severity of impairment in chronic (> 3 months) mTBI and poorer balance performance was mediated by sensorimotor integration measures. METHODS: Data were collected from 61 healthy controls and 58 mTBI participants suffering persistent balance problems. Participants completed questionnaires (Dizziness Handicap Inventory (DHI), Neurobehavioral Symptom Inventory (NSI), and Sports Concussion Assessment Tool Symptom Questionnaire (SCAT2)) and performed instrumented postural sway assessments and a test of Central Sensory Motor Integration (CSMI). Exploratory Factor Analysis was used to reduce the variables used within the mediation models to constructs of impairment (Impairment Severity - based on questionnaires), balance (Sway Dispersion - based on instrumented postural sway measures), and sensorimotor control (Sensory Weighting, Motor Activation and Time Delay - based on parameters from CSMI tests). Mediation analyses used path analysis to estimate the direct effect (between impairment and balance) and indirect (mediating) effects (from sensorimotor control). RESULTS: Two out of three sensorimotor integration factors (Motor Activation and Time Delay) mediated the relationship between Impairment Severity and Sway Dispersion, however, there was no mediating effect of Sensory Weighting. SIGNIFICANCE: These findings have clinical implications since rehabilitation of balance commonly focuses on sensory cues. Our findings indicate the importance of Motor Activation and Time Delay, and thus a focus on strategies to improve factors related to these constructs throughout the rehabilitative process (i.e., level of muscular contractions to control joint torques; response time to stimuli/perturbations) may improve a patient's balance control.