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Identifying risk factors for musculoskeletal (MSK) injury is critical to maintain the health and safety of athletes. While current tests consider isolated assessments of function or subjective ratings, objective tests of reactive postural responses, especially when in cognitively demanding scenarios, may better identify risk of MSK injury than traditional tests alone.ObjectivesTo examine if objective assessments of reactive postural responses, quantified using wearable inertial measurement units, are associated with the risk for acute lower extremity MSK injuries in collegiate athletes.DesignProspective survival analysisMethods191 Division I NCAA athletes completed an instrumented version of a modified Push and Release (I-mP&R) test at the beginning of their competitive season. The I-mP&R was performed with eyes closed under single- and dual-task (concurrent cognitive task) conditions. Inertial measurement units recorded acceleration and angular velocity data that was used to calculate time to stability (TTS). Acute lower extremity MSK injuries were tracked from first team activity for six months. Cox proportional hazard models were used to determine if longer times to stability were associated with faster time to injury.ResultsLonger TTS was associated with increased risk of injury; every 250 ms increase in dual-task median TTS was associated with a 37% increased risk of acute, lower-extremity MSK injury.ConclusionTests of reactive balance, particularly under dual-task conditions, may be able to identify athletes at risk of acute lower extremity MSK injury. Clinically-feasible, instrumented tests of reactive should be considered in assessments for prediction and prevention of MSK injury in collegiate athletes.

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.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.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.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 available at: http://links.lww.com/JNPT/A409).

Background and ObjectivesRecent team-based models of care use symptom subtypes to guide treatments of individuals with chronic effects of mild traumatic brain injury (mTBI). However, these subtypes, or phenotypes, may be too broad, particularly for balance (e.g., vestibular subtype). To gain insight into mTBI-related imbalance, we (1) explored whether a dominant sensory phenotype (e.g., vestibular impaired) exists in the chronic mTBI population, (2) determined the clinical characteristics, symptomatic clusters, functional measures, and injury mechanisms that associate with sensory phenotypes for balance control in this population, and (3) compared the presentations of sensory phenotypes between individuals with and without previous mTBI.MethodsA secondary analysis was conducted on the Long-Term Impact of Military-Relevant Brain Injury Consortium—Chronic Effects of Neurotrauma Consortium. Sensory ratios were calculated from the sensory organization test, and individuals were categorized into 1 of the 8 possible sensory phenotypes. Demographic, clinical, and injury characteristics were compared across phenotypes. Symptoms, cognition, and physical function were compared across phenotypes, groups, and their interaction.ResultsData from 758 Service Members and Veterans with mTBI and 172 individuals with no lifetime history of mTBI were included. Abnormal visual, vestibular, and proprioception ratios were observed in 29%, 36%, and 38% of people with mTBI, respectively, with 32% exhibiting more than 1 abnormal sensory ratio. Within the mTBI group, global outcomes (p < 0.001), self-reported symptom severity (p < 0.027), and nearly all physical and cognitive functioning tests (p < 0.027) differed across sensory phenotypes. Individuals with mTBI generally reported worse symptoms than their non-mTBI counterparts within the same phenotype (p = 0.026), but participants with mTBI in the vestibular-deficient phenotype reported lower symptom burdens than their non-mTBI counterparts (e.g., mean [SD] Dizziness Handicap Inventory = 4.9 [8.1] for mTBI vs 12.8 [12.4] for non-mTBI, group × phenotype interaction p < 0.001). Physical and cognitive functioning did not differ between the groups after accounting for phenotype.DiscussionIndividuals with mTBI exhibit a variety of chronic balance deficits involving heterogeneous sensory integration problems. While imbalance when relying on vestibular information is common, it is inaccurate to label all mTBI-related balance dysfunction under the vestibular umbrella. Future work should consider specific classification of balance deficits, including specific sensory phenotypes for balance control.

OBJECTIVE: Balance testing after concussion or mild traumatic brain injury (mTBI) can be useful in determining acute and chronic neuromuscular deficits that are unapparent from symptom scores or cognitive testing alone. Current assessments of balance do not comprehensively evaluate all three classes of balance: maintaining a posture, voluntary movement, and reactive postural response. Despite the utility of reactive postural responses in predicting fall risk in other balance impaired populations, the effect of mTBI on reactive postural responses remains unclear. This review sought to (1) examine the extent and range of available research on reactive postural responses in people post-mTBI and (2) determine if reactive postural responses (balance recovery) are affected by mTBI. DESIGN: Scoping review METHODS: Studies were identified using Medline, Embase, CINAHL, Cochrane Library, Dissertations and Theses Global, PsycINFO, SportDiscus, and Web of Science. Inclusion criteria were: injury classified as mTBI with no confounding central or peripheral nervous system dysfunction beyond those stemming from the mTBI, quantitative measure of reactive postural response, and a discrete, externally driven perturbation was used to test reactive postural response. RESULTS: A total of 4,747 publications were identified and a total of three studies (5 publications) were included in the review. CONCLUSION: The limited number of studies available on this topic highlight the lack of investigation on reactive postural responses after mTBI. This review provides a new direction for balance assessments after mTBI and recommends incorporating all three classes of postural control in future research.

Context: Current clinical concussion evaluations assess balance deficits using static or dynamic balance tasks while largely ignoring reactive balance. Including a reactive balance assessment in current evaluations might provide a more comprehensive concussion evaluation. Objective: The purpose of this study was to determine if redundancy exists within current clinical baseline assessments of concussion and whether reactive balance adds unique information to these evaluations. Design: Cross Sectional Study Setting: Clinical Assessment Patients or Other Participants: Two cohorts of data were collected at the beginning of the athletic season from healthy NCAA Division I athletes. Within the first cohort (n = 191), correlation analyses with clinical scores and inertial measurements were run between the ImPACT (Immediate Post-Concussion Assessment and Cognitive Tool), the BESS (Balance Error Scoring System), the modified Push and Release (mP&R), and instrumented mP&R (I-mP&R) to determine the strength of a relationship between these concussion tests. Within the second cohort (n = 88), correlation analyses were run between the BESS, the mP&R, Timed Tandem Gait, Walking with eyes closed, and clinical reaction time to determine the strength of the relationship between these concussion evaluation tests. Main Outcome Measures: ImPACT cognitive indices, BESS and mP&R clinical score and instrumented measures (BESS sway; I-mP&R time to stability, latency, and step length), TTG and Walking time to completion, and clinical reaction time. Results: The strongest inter-instrument correlation value was r= 0.347, which was considered a weak correlation, between clinical reaction time and single task time to stability from the I-mP&R. The I-mP&R and mP&R clinical scores were weakly associated with the other assessments. Conclusion: The weak correlations between inter-assessment variables indicates that there is little redundancy within the current clinical evaluations. Furthermore, reactive balance represents a unique domain of function that may improve the comprehensiveness of clinical assessments.

Background Turning is a component of gait that requires planning for movement of multiple body segments and the sophisticated integration of sensory information from the vestibular, visual, and somatosensory systems. These aspects of turning have led to growing interest to quantify turning in clinical populations to characterize deficits or identify disease progression. However, turning may be affected by environmental differences, and the degree to which turning assessments are comparable across research or clinical sites has not yet been evaluated. Research question The aim of this study was to determine the extent to which peak turning speeds are equivalent between two sites for a variety of mobility tasks. Methods Data were collected at two different sites using separate healthy young adult participants (n = 47 participants total), but recruited using identical inclusion and exclusion criteria. Participants at each site completed three turning tasks: a one-minute walk (1 MW) along a six-meter walkway, a modified Illinois Agility Test (mIAT), and a custom clinical turning course (CCTC). Peak yaw turning speeds were extracted from wearable inertial sensors on the head, trunk, and pelvis. Between-site differences and two one-sided tests (TOST) were used to determine equivalence between sites, based on a minimum effect size reported between individuals with mild traumatic brain injury and healthy control subjects. Results No outcomes were different between sites, and equivalence was determined for 6/21 of the outcomes. These findings suggest that some turning tasks and outcome measures may be better suited for multi-site studies. The equivalence results are also dependent on the minimum effect size of interest; nearly all outcomes were equivalent across sites when larger minimum effect sizes of interest were used. Significance Together, these results suggest some tasks and outcome measures may be better suited for multi-site studies and literature-based comparisons.

Background People with multiple sclerosis (PwMS) frequently experience dizziness and imbalance that may be caused by central vestibular system dysfunction. Vestibular rehabilitation may offer an approach for improving dysfunction in these people. Objective To test the efficacy of a gaze and postural stability (GPS) retraining intervention compared to a strength and endurance (SAE) intervention in PwMS. Methods About 41 PwMS, with complaints of dizziness or history of falls, were randomized to either the GPS or SAE groups. Following randomization participants completed 6-weeks of 3×/week progressive training, delivered one-on-one by a provider. Following intervention, testing was performed at the primary (6-weeks) and secondary time point (10-weeks). A restricted maximum likelihood estimation mixed effects model was used to examine changes in the primary outcome of the Dizziness Handicap Inventory (DHI) between the 2 groups at the primary and secondary time point. Similar models were used to explore secondary outcomes between groups at both timepoints. Results Thirty-five people completed the study (17 GPS; 18 SAE). The change in the DHI at the primary time point was not statistically different between the GPS and SAE groups (mean difference = 2.33 [95% CI −9.18, 12.85]). However, both groups demonstrated significant improvement from baseline to 6-weeks (GPS −8.73; SAE −7.31). Similar results were observed for secondary outcomes and at the secondary timepoint. Conclusions In this sample of PwMS with complaints of dizziness or imbalance, 6-weeks of GPS training did not result in significantly greater improvements in dizziness handicap or balance compared to 6-weeks of SAE training.

Dizziness after mild traumatic brain injury (mTBI) is commonly attributed to impairment within the vestibular system. However, oculomotor, mobility, and autonomic dysfunction can also contribute to patient-reported dizziness. The purpose of this preliminary study was to examine whether a multimodal battery of assessments could help explain patient-reported dizziness after mTBI. Twenty-three participants with concussion-related symptoms completed the Dizziness Handicap Inventory (DHI) to evaluate burden imposed by dizziness on daily activities and a battery of tests designed to incorporate domains that have been shown to contribute to dizziness (e.g., vestibular, oculomotor, balance and mobility, and autonomic dysfunction). Specific outcomes included quantitative variables obtained from: Vestibular Ocular Motor Screening (VOMS); standing for 30 seconds with feet together, eyes closed, with hands on their hips on both firm and foam surfaces; walking for one minute at a comfortable pace; and a Head-up Tilt (HUT) Test. Univariate associations between DHI and individual measures were assessed, and a backwards-stepwise regression model determined the multi-variable association. There were no strong associations and only a few moderate associations between individual functional measure and DHI total score. A total of eight variables had univariate correlation coefficients larger than 0.20 in magnitude. The final model from the backwards-stepwise procedure explained 69% of the variance in DHI and retained only three variables: peak turning speed from the one-minute walk; mean blood pressure (MBP) during the HUT; and the total VOMS score. Isolated assessments of individual domains of function have weak-to-moderate associations with post-mTBI dizziness. Conversely, a multivariable model that contained measures of mobility, autonomic function, and symptomatic complaints to vestibular and ocular provocation explained 69% of the variance in dizziness. These results suggest that dizziness is physiologically heterogeneous in nature and support the use of multi-domain assessments in patients with dizziness after mTBI.

Globally, there are 3 million people living with multiple sclerosis (PLW-MS). A large proportion of PLW-MS have abnormal vestibular function tests that suggest central vestibular lesions. Yet, data regarding vestibular-ocular control in PLW-MS is limited. Thus, we aimed to further characterize compensatory saccade (CS) behavior in PLW-MS.We analyzed video head impulse data from four groups of six age- and sex-matched adults: people living with mild MS (PLW-mild-MS, people living with moderate MS (PLW-moderate-MS), people living with unilateral vestibular deafferentation (PLW-UVD), and healthy controls (HC).PLW-moderate-MS had lower lateral canal vestibulo-ocular reflex (VOR) gain bilaterally compared to PLW-mild MS (p 0.001), HC (p 0.001), and PLW-UVD (p 0.001). CS frequency was higher for impulses towards the less affected side in PLW-moderate-MS versus the more (p = 0.01) and less (p 0.001) affected sides in PLW-mild-MS. CS latency was shorter (p 0.001) and CS peak velocity was lower (p 0.001) with impulses towards the more affected side versus the less affected side in PLW-moderate-MS. However, CS peak velocity with impulses towards each side was similar in PLW-mild-MS (p = 0.12). Gaze position error (GPE) was larger after impulses towards the more affected side versus the less affected side in PLW-moderate-MS (p 0.001) and PLW-mild-MS (p 0.001). MS-related disability was moderately associated with VOR gain (p 0.001) and GPE (p 0.001). Additionally, we identified micro-saccades and position correcting saccades that were uniquely employed by PLW-MS as compensatory gaze stabilizing strategies.In PLW-MS, the characteristics of compensatory oculomotor behavior depend on the extent of residual VOR gain.

OBJECTIVE: The purpose of this study was to (1) explore differences in vestibular ocular motor screening (VOMS) symptoms between healthy adults and adults with persistent symptoms after mild traumatic brain injury (mTBI), and (2) explore the relationships between VOMS symptoms and other measures (self-reported vestibular symptoms, clinical measures of balance and gait, and higher-level motor ability tasks). SETTING: Research laboratory setting. PARTICIPANTS: Fifty-three persons with persistent symptoms (>3 weeks) following mTBI and 57 healthy controls were recruited. Eligibility for participation included being 18 to 50 years of age and free of medical conditions that may affect balance, with the exception of recent mTBI for the mTBI group. DESIGN: Cross-sectional. MAIN MEASURES: The primary outcomes were the VOMS symptom scores and near point of convergence (NPC) distance. Secondary outcomes included the Dizziness Handicap Inventory (DHI) total and subdomain scores, sway area, Functional Gait Analysis total score, gait speed, and modified Illinois Agility Task completion time, and Revised High-Level Mobility Assessment Tool total score. RESULTS: The mTBI group reported more VOMS symptoms (z range, -7.28 to -7.89) and a further NPC (t = -4.16) than healthy controls (all Ps < .001). DHI self-reported symptoms (total and all subdomain scores) were strongly associated with the VOMS symptom scores (rho range, 0.53-0.68; all Ps < .001). No significant relationships existed between VOMS symptoms and other measures. CONCLUSION: Significant group differences support the relevance of the VOMS for mTBI in an age-diverse sample with persistent symptoms. Furthermore, strong association with DHI symptoms supports the ability of the VOMS to capture vestibular complaints in this population.

Context: Traditional assessments of reactive balance require sophisticated instrumentation to ensure objective, highly repeatable paradigms. This instrumentation is clinically impractical. The Push and Release test (P&R) is a well-validated clinical test that examines reactive balance, and the application of wearable inertial measurement units (IMU) enables sensitive and objective assessment of this clinically feasible test. The P&R relies on administrator experience and may be susceptible to interadministration reliability concerns. The purpose of this study was to evaluate the interadministrator reliability of objective outcomes from an instrumented, modified version of the P&R test. Design: Crossover interadministrator design. Methods: Twenty healthy adults (20–35 y) completed the P&R in 4 directions with 2 different administrators. Measures quantified using IMUs included step latency, step length, and time to stability. Lean angle (LA) at release was used as a measure of administration consistency. The intraclass correlation coefficient (ICC) estimate was used to assess interadministrator reliability in each direction. To determine consistency of LA within and across administrators, we calculated the SDs for each rater by direction and the interadministrator reliability of LA using ICC. Results: Across individual directions, the ICC for agreement between raters ranged from .16 to .39 for step latency, from .52 to .62 for time to stability, and from .48 to .84 for step length. Summary metrics across all 4 directions produced higher ICC values. There was poor to moderate consistency in administration based on LA, but LA did not significantly affect any of the outcomes. Conclusion: The modified P&R yields moderate interadministrator reliability and high validity. Summary metrics over all 4 directions (the maximum step latency, the median time to stability, and the median step length) are likely more reliable than direction-specific scores. Variations in body size should also be considered when comparing populations.

Background and Purpose:Cognition has been linked to rehabilitation outcomes in stroke populations, but this remains unexplored in individuals with Parkinson's disease (PD). The purpose of this secondary data analysis from a recent clinical trial (NCT02600858) was to determine if global cognition was related to skill performance after motor training in individuals with PD.Methods:Twenty-three participants with idiopathic PD completed 3 days of training on an upper-extremity task. For the purposes of the original clinical trial, participants trained either “on” or “off” their dopamine replacement medication. Baseline, training, and 48-h retention data have been previously published. Global cognition was evaluated using the Montreal Cognitive Assessment (MoCA). Linear regression examined whether MoCA score predicted longer-term retention at nine-day follow-up; baseline motor task performance, age, PD severity, depressive symptoms, and group (medication “on”/“off”) were included as covariates. Baseline and follow-up motor task performance were assessed for all participants while “on” their medication.Results:MoCA score was positively related to follow-up motor task performance, such that individuals with better cognition were faster than those with poorer cognition. Baseline task performance, age, PD severity, depressive symptoms, and medication status were unrelated to follow-up performance.Discussion and Conclusions:Results of this secondary analysis align with previous work that suggest cognitive impairment may interfere with motor learning in PD and support the premise that cognitive training prior to or concurrent with motor training may enhance rehabilitative outcomes for individuals with PD. Findings also suggest that assessing cognition in individuals with PD could provide prognostic information about their responsiveness to motor rehabilitation.

Objective Previous short duration studies have demonstrated that high-intensity aerobic exercise improves aspects of motor and non-motor function in people with Parkinson disease (PwPD); however, the effectiveness of a long-term exercise intervention on slowing disease progression is unknown. The primary aim of this study is to determine the disease-altering effects of high-intensity aerobic exercise, administered on an upright stationary cycle, on the progression of PD. A secondary aim is to develop a prognostic model for 12-month changes in the Movement Disorder Society Unified Parkinson's Disease Rating Scale III (MDS-UPDRS III) of PwPD undergoing an aerobic exercise intervention. Methods This pragmatic, multisite, single-rater blinded, randomized controlled trial will recruit PwPD from 2 large, urban, academic medical centers. Participants (N = 250 PwPD) will be randomized to (1) home-based aerobic exercise or (2) usual and customary care. Those in the aerobic exercise arm will be asked to complete in-home aerobic exercise sessions at 60% to 80% of heart rate reserve 3 times per week for 12 months utilizing a commercially available upright exercise cycle. The usual and customary care group will continue normal activity levels. Daily activity will be monitored for both groups throughout the 12-month study period. The primary outcome, both to assess disease-modifying response to aerobic exercise and for prognostic modeling in the aerobic exercise arm, is 12-month rate of change in the MDS-UPDRS III. Clinical and biomechanical measures will also be used to assess upper and lower extremity motor function as well as non-motor functions. Impact Should long-term aerobic exercise demonstrate disease-modifying capability, this study will provide evidence that “Exercise is Medicine” for PwPD. Further, the derived prognostic model will inform a patient-specific exercise prescription for PwPD and expected effects on PD progression.

Background: Psychometric properties of tests that assess the angular vestibulo-ocular reflex (aVOR) and vestibulospinal reflex function are currently unknown. This study investigated the test-retest reliability and response stability of gaze stabilization, postural sway, and dynamic balance measures in persons with multiple sclerosis (MS) and controls. Methods: Nineteen adults with MS and 14 controls performed passive horizontal head impulses, quiet standing, and dynamic balance tests on two separate occasions. Gaze stabilization measures included aVOR gain, number of compensatory saccades (CSs) per head rotation, CS latency, and gaze position error. Postural sway included sway amplitude and total sway path. Dynamic balance measure included the Functional Gait Assessment. Intraclass correlation coefficient, standard error of measurement (SEM, SEM%), and minimal detectable difference at 95% confidence level were calculated. Results: Test-retest reliability for aVOR gain, CSs per head rotation, and gaze position error was moderate and for each postural sway and dynamic balance measure was good. Low error (SEM, SEM%) for aVOR gain, CS latency, postural sway, and dynamic balance variables and low minimal detectable difference values for aVOR gain and Functional Gait Assessment scores were seen, suggestive of acceptable response stability. Conclusions: These results support the utility of some of the gaze and postural measures for examination and treatment efficacy purposes in people with MS.

Introduction. Treatment of Parkinson’s disease (PD) with exogenous dopamine (ie, levodopa) may positively affect motor symptoms, but may negatively affect other functions such as the learning of motor skills necessary for rehabilitation. This study aimed to determine whether levodopa medication affects general and sequence-specific learning of a stepping task and the transfer of movement skill to untrained balance tasks in people with PD. Methods. Participants with PD were randomized to practice “on” (n = 14) or “off” (n = 13) levodopa medication. Participants practiced 6 blocks of 6 trials of 24 steps of a stepping task over an acquisition period of 3 consecutive days, followed by single retention blocks of 6 trials 2 and 9 days later. Participants were also assessed on untrained balance (ie, transfer) tasks “on” levodopa before practice and following late retention. Results. There were no between-group differences in general learning, sequence-specific learning, or transfer of skill to untrained balance tasks ( P > .05). Both groups demonstrated general and sequence-specific learning ( P < .001) and trends for improvement in untrained tasks ( P < .001 to P = .26) following practice. Detailed analysis of early acquisition revealed no difference between medication groups. Conclusion. People with PD improved performance on the stepping task with practice. The between-group effect sizes were small, suggesting that levodopa medication status (“on” versus “off”) during practice did not significantly affect general or sequence-specific learning of the task or components of early acquisition. The practice dose required to optimally result in functional improvements in untrained balance tasks, including reductions in falls, remains to be determined.

Background and PurposeCognitive impairment has been linked to poor motor learning and rehabilitation outcomes in older adult and stroke populations, but this remains unexplored in individuals with Parkinson disease (PD). The purpose of this secondary data analysis from a recent clinical trial (NCT02600858) was to determine if global cognition was related to nine-day skill retention after upper-extremity motor training in individuals with PD.MethodsTwenty-three participants with idiopathic PD completed three consecutive days of training on an upper-extremity task. For the purposes of the original clinical trial, participants trained either “on” or “off” their dopamine replacement medication. Baseline, training, and shorter-term (48-hour) retention data have been previously published. Global cognition was evaluated using the Montreal Cognitive Assessment (MoCA). Participant age, baseline performance, MoCA score, and group (medication “on”/”off”) were included in a multivariate linear regression model to predict longer-term (nine day) follow-up performance. Baseline and follow-up performance were assessed for all participants while “on” their medication.ResultsMoCA score was positively related to follow-up performance, such that individuals with better cognition performed better than those with poorer cognition. Participant age, baseline performance, and medication status were unrelated to follow-up performance.Discussion and ConclusionsResults of this secondary analysis align with previous work that suggest cognitive impairment may interfere with motor learning in PD, and that assessing cognition could provide prognostic information about an individual’s responsiveness to motor rehabilitation for a number of clinical populations.

Background Motor learning has been investigated using various paradigms, including serial reaction time tasks (SRTT) that examine upper extremity reaching and pointing while seated. Few studies have used a stepping SRTT, which could offer additional insights into motor learning involving postural demands. For a task to measure motor learning, naive participants must demonstrate a) improved performance with task practice, and b) a dose-response relationship to learning the task. Research question Is a stepping SRTT feasible and efficacious for measuring motor learning? Methods In this prospective study, 20 participants stood on an instrumented mat and were presented with stimuli on a computer screen. They stepped to the corresponding positions on the mat as quickly as possible. Presented stimuli included random sequences and a blinded imbedded repeating sequence. Three days after completing the randomly assigned practice dose [high dose group (n = 10) performed 4320 steps; low dose group (n = 10) performed 144 steps], a retention test of 72 steps was performed. Feasibility was measured as the proportion of participants who completed the assigned practice dose without adverse events. Efficacy was measured as within-group performance improvement on the random sequences and on the repeating sequence (paired t-tests), as well as a dose-response relationship to learning both types of sequences (independent t-tests). Results All participants (mean age 26.8 years) completed all practice sessions without adverse events, indicating feasibility. High dose practice resulted in performance improvement while low dose did not; a dose-response relationship was found, with high dose practice resulting in greater learning of the task than low dose practice, indicating efficacy. Significance This stepping SRTT is a feasible and efficacious way to measure motor learning, which could provide critical insights into anticipatory stepping, postural control, and fall risk. Future research is needed to determine feasibility, efficacy, and optimal practice dosages for older and impaired populations.

Advances in medical management of Parkinson's disease (PD) have resulted in living longer with disability. Although disability worsens over the course of the disease, there are signs of disability even in the early stages. Several studies reveal an early decline in gait and balance and a high prevalence of nonmotor signs in the prodromal period that contribute to early disability. There is a growing body of evidence revealing the benefits of physical therapy and exercise to mitigate motor and nonmotor signs while improving physical function and reducing disability. The presence of early disability coupled with the benefits of exercise suggests that physical therapy should be initiated earlier in the disease. In this review, we present the evidence revealing early disability in PD and the effectiveness of physical therapy and exercise, followed by a discussion of a secondary prevention model of rehabilitation to reduce early disability and optimize long-term outcomes.

Rehabilitation therapies are critical for optimizing quality-of-life and daily functions for individuals living with Parkinson's disease (PD). Thus, understanding the patterns of and under what conditions physicians make rehabilitation referrals is important for optimizing care.We analyzed data from 5020 participants (4 countries) collected from 1/3/2016 to 4/20/2018 as part of the Parkinson's Foundation Quality Improvement Initiative (PF QII). Data were analyzed for single discipline and multidiscipline referrals to speech language pathology (SLP), physical therapy (PT), and occupational therapy (OT). Group comparisons (referred vs. not-referred) and regression procedures were implemented to determine demographic and clinical variables that were associated with an increased likelihood of rehabilitation referral.35.3% of participants were referred to rehabilitation services. Of these, 25.1% received a multidiscipline referral. There was a statistically significant effect of disease stage on both single discipline (χDespite evidence supporting multidiscipline and proactive rehabilitation in PD, the majority of referrals were made to a single service and may be reactions to falls or advancing disease. Data suggest there may be missed opportunities for optimizing care through proactive rehabilitation interventions.

Background Multiple sclerosis (MS) is a debilitating, neurodegenerative disorder causing considerable gait and balance dysfunction. Reactive balance (i.e., quick movements in response to a loss of balance) is particularly important for fall risk and is impaired in people with MS compared to neurotypical peers. Therefore, improving reactive balance among those with MS is critical. However, for maximum ecological validity, improvements in reactive balance through training would be demonstrable upon first loss-of-balance, rather than an average of several trials as is typically reported. This study evaluated changes in performance on the first stepping trial in people with MS after one day of practice. Methods Fourteen people with MS underwent two, consecutive days of support-surface perturbations from stance. On day 1, participants underwent a single backward-stepping trial, followed by 35 practice trails (forward and backward). Approximately 24 h later, participants were again exposed to a single backward stepping perturbation. Protective stepping outcomes were step length, step latency, and margin of stability at first foot contact. The backward step performance on the first trial of days one and two were compared, and difference scores were evaluated for relationships with correlates based on theoretical considerations. Findings First-trial margin of stability increased (improved) from day 1 to day 2 (P = .016). Steps were also faster on average by approximately 5 ms on day 2, although this improvement was not significant (P = .062). Interpretations Although preliminary, these findings provide evidence that individuals with MS may be able to experience first-trial improvements after a low dose of perturbation training.

Motor performance is classically described as improving nonlinearly with practice, demonstrating rapid improvements early in practice with stabilization later, which is commonly modeled by exponential decay functions. However, retrospective analyses of our previously collected data challenge this theoretical model of motor skill acquisition, suggesting that a majority of individual learners actually demonstrate patterns of motor improvement different from this classical model. A convenience sample of young adults, older adults, and people with Parkinson disease trained on the same functional upper-extremity task. When fitting three-parameter exponential decay functions to individual participant data, the authors found that only 13.3% of young adults, 40.9% of older adults, and 66.7% of adults with Parkinson disease demonstrated this “classical” skill acquisition pattern. Thus, the three-parameter exponential decay pattern may not well-represent individuals’ skill acquisition of complex motor tasks; instead, more individualized analysis methods may be warranted for advancing a theoretical understanding of motor skill acquisition.

Determining readiness for duty after mild traumatic brain injury (mTBI) is essential for the safety of service members and their unit. Currently, these decisions are primarily based on self-reported symptoms, objective measures that assess a single system, or standardized physical or cognitive tests that may be insensitive or lack ecological validity for warrior tasks. While significant technological advancements have been made in a variety of assessments of these individual systems, assessments of isolated tasks are neither diagnostically accurate nor representative of the demands imposed by daily life and military activities. Emerging evidence suggests that complex tasks, such as dual-task paradigms or turning, have utility in probing functional deficits after mTBI. Objective measures from turning tasks in single- or dual-task conditions, therefore, may be highly valuable for clinical assessments and return-to-duty decisions after mTBI. The goals of this study are to assess the diagnostic accuracy, predictive capacity, and responsiveness to rehabilitation of objective, dual-task turning measures within an mTBI population. These goals will be accomplished over two phases. Phase 1 will enroll civilians at three sites and active-duty service members at one site to examine the diagnostic accuracy and predictive capacity of dual-task turning outcomes. Phase 1 participants will complete a series of turning tasks while wearing inertial sensors and a battery of clinical questionnaires, neurocognitive testing, and standard clinical assessments of function. Phase 2 will enroll active-duty service members referred for rehabilitation from two military medical treatment facilities to investigate the responsiveness to rehabilitation of objective dual-task turning measures. Phase 2 participants will complete two assessments of turning while wearing inertial sensors: a baseline assessment prior to the first rehabilitation session and a post-rehabilitation assessment after the physical therapist determines the participant has completed his/her rehabilitation course. A variable selection procedure will then be implemented to determine the best task and outcome measure for return-to-duty decisions based on diagnostic accuracy, predictive capacity, and responsiveness to rehabilitation. Overall, the results of this study will provide guidance and potential new tools for clinical decisions in individuals with mTBI.Clinical Trial Registration:clinicaltrials.gov, Identifier NCT03892291.

To use clinically available inertial measurement units to quantify the control of linear accelerations at the head and trunk during gait in different sensory conditions in individuals with unilateral vestibular loss.Observational study.Outpatient research laboratory.Individuals (n=13; mean age, 47.6±13.7y; 69% women) 6 weeks after vestibular schwannoma resection surgery and vestibular healthy participants (n=16; mean age, 29.7±5.9y; 56% women).Not applicable.Walking speed normalized, root mean square values of cranial-caudal, medial-lateral, and anterior-posterior directed linear accelerations at the head and the trunk while walking in 2 visual sensory conditions (eyes open and eyes closed).Linear mixed models for each root mean square value were fit on the effects of group, condition, and group by condition. The group by condition effect was used to examine the primary hypothesis that individuals with vestibular loss would experience greater change in triplanar root mean square values at the head and trunk from the eyes open to eyes closed condition compared with the vestibular healthy group. The group by condition effect was found to be significant at the head in the cranial-caudal (β=0.39; P=.002), medial-lateral (β=0.41; P.001), and anterior-posterior (β=0.43; P.001) directions. The group by condition effect was also significant in the cranial-caudal (β=0.39; P=.002), medial-lateral (β=0.39; P.001), and anterior-posterior (β=0.23; P=.002) directions at the trunk.Participants who underwent vestibular schwannoma resection were more impaired in their ability to control accelerations at the head and trunk without visual sensory information than vestibular healthy participants. These impairments were detectable using clinically available inertial measurement units.

Objective To determine whether improvements in protective stepping experienced after repeated support surface translations generalize to a different balance challenge in people with multiple sclerosis (PwMS) Background MS affects almost 1 million people in the United States and impairs balance and mobility. Perturbation practice can improve aspects of protective stepping in PwMS, but whether these improvements generalize is unknown. Methods Fourteen PwMS completed two visits, 24hrs apart. The balance tasks included tether-release trials and support surface translations on a treadmill eliciting backward protective stepping. Margin of stability, step length, and step latency were calculated. Generalization was assessed via multilevel mediation models (MLMM) with bootstrapping to produce percentile and bias corrected confidence intervals Results There were no mediated effects for margin of stability or step latency; however, mediation was observed for step length, indicating that participants increased step length throughout the treadmill trials, and this generalized to tether-release trials Discussion MLMM may be useful for evaluating generalization of motor training to novel balance situations, particularly in small sample sizes. Using these analyses, we observed PwMS generalized improvements in step length, suggesting that aspects of protective step training may translate to improvements in other reactive balance tasks in PwMS.

Background and Purpose: Adherence to physical therapy (PT) and secondary prevention programs (SPPs) is particularly low for individuals with Parkinson's disease. Preliminary research has linked perceptions of caring climates as well as enhanced tripartite efficacy perceptions to adherence during rehabilitation programs. In light of such preliminary research, the purpose of this study was threefold: (1) to examine relationships between perceptions of a caring climate and the 3 efficacy constructs within the tripartite model, (2) to examine the relationship between the tripartite efficacy constructs and adherence to PT/SPP exercises, and (3) to determine whether tripartite efficacy beliefs mediated the relationship between caring climate perceptions and adherence. Method: A total of 77 individuals with Parkinson's disease who were currently or recently enrolled in PT or an SPP were recruited and surveyed about their perceptions of the caring climate of their rehabilitation clinic, their tripartite efficacy perceptions, and their adherence to rehabilitation. Correlations and a multiple mediation analysis were conducted to address the purposes of this study. Results and Discussion: Results showed significant positive associations between all variables; however, all paths within the proposed mediation model were not significant. Specifically, the c paths linking the tripartite efficacy constructs with adherence were not significant. A follow-up analysis was undertaken to address potential suppression effects within the mediating variables, and this analysis revealed a statistically significant model with relation-inferred self-efficacy (RISE) as a sole mediator of the relationship between caring perceptions and adherence to rehabilitation. Conclusions: Several practical implications can be gleaned from the current study. First, practitioners should strive to enhance the caring climate of their clinic by employing techniques reported in previous literature, such as creating a supportive atmosphere, displaying benevolence, and paying attention. In addition, the results suggest that individuals' RISE perceptions, in particular, could be a viable target for enhancing adherence.

Despite the common complaints of dizziness and demyelination of afferent or efferent pathways to and from the vestibular nuclei which may adversely affect the angular vestibulo-ocular reflex (aVOR) and vestibulo-spinal function in persons with multiple sclerosis (PwMS), few studies have examined gaze and dynamic balance function in PwMS. (1) Determine the differences in gaze stability, dynamic balance and participation measures between PwMS and controls, (2) Examine the relationships between gaze stability, dynamic balance and participation. Nineteen ambulatory PwMS at fall-risk and 14 age-matched controls were recruited. Outcomes included (1) gaze stability (angular aVOR gain [ratio of eye to head velocity]; number of compensatory saccades [CS] per head rotation; CS latency; gaze position error; coefficient of variation [CV] of aVOR gain), (2) dynamic balance (functional gait assessment, FGA; four square step test), and (c) participation (dizziness handicap inventory; activities-specific balance confidence scale). Separate independent t-tests and Pearson's correlations were calculated. PwMS were age = 53 ± 11.7 years and had 4.2 ± 3.3 falls/year. PwMS demonstrated significant (P < 0.05) impairments in gaze stability, dynamic balance and participation measures compared to controls. CV of aVOR gain and CS latency were significantly correlated with FGA. Deficits and correlations across a spectrum of disability measures highlight the relevance of gaze and dynamic balance assessment in PwMS. Anat Rec, 301:1852-1860, 2018. © 2018 Wiley Periodicals, Inc.

Background Sequence-specific learning (SSL); the ability to implicitly integrate repeated sequences compared to random sequences during a motor sequence paradigm, is impaired in healthy elders (HE) compared to healthy young (HY). Prior studies have provided limited practice (small repetitions and only 1 to 3 days). Research question Using a standing, postural control task we sought to assess if more practice (7 days) would remediate the differences observed in SSL for HE. Methods We used a continuous tracking task following a sinusoidal path of randomly presented random and repeated patterns. Root mean square error (RMSE) was the primary dependent variable, and the difference in RMSE between the random and repeated sequences was calculated to determine if SSL occurred. Results Improvement in SSL was documented as a decreasing value of the mean repeated sequence and less or no change in the random sequence. Eight HY and 8 HE practiced the repeated sequences 420 times over 7 days. No differences were observed between the groups on cognition, balance, and mobility. HE did not demonstrate the ability to integrate the repeated sequence on day 1, but with increased practice, they integrated the repeated sequence similar to HY by the end of practice. The results of this study suggest that sustained practice over 7 days remediated differences in performance of a standing, implicit, sequence-specific task between HY and HE. Significance Clinically, it is important to provide individuals with sufficient practice amount to achieve integration of a standing task. Results suggest that older adults need more practice to demonstrate SSL.

Background The ability to adapt postural responses to sensory illusions diminishes with age and is further impaired by Parkinson disease. However, limited information exists regarding training-related adaptions of sensory reweighting in these populations. Methods This study sought to determine whether Parkinson disease or age would differentially affect acute postural recovery or adaptive postural responses to novel or repeated exposure to sensory illusions using galvanic vestibular stimulation during quiet stance. Findings Acutely, individuals with Parkinson disease demonstrated larger center of pressure coefficient of variation compared to controls. Unlike individuals with Parkinson disease and asymptomatic older adults, healthy young adults acutely demonstrated a reduction in Sample Entropy to the sensory illusion. Following a period of consolidation Sample Entropy increased in the healthy young group, which coincided with a decreased center of pressure coefficient of variation. Similar changes were not observed in the Parkinson disease or older adult groups. Interpretation Taken together, these results suggest that young adults learn to adapt to vestibular illusion in a more robust manner than older adults or those with Parkinson disease. Further investigation into the nature of this adaptive difference is warranted.

Addressing muscle deficits within a multi-component exercise fall reduction program is a priority, especially for the highest risk older adults, i.e., those who have fallen previously. Eccentric resistance exercise with its high-force producing potential, at a low energetic cost, may be ideally-suited to address muscle impairments in this population. The purpose of this study was to compare the effects of resistance exercise via negative, eccentrically-induced, work (RENEW) versus traditional (TRAD) resistance exercise on mobility, balance confidence, muscle power and cross sectional area, as well as the number of days high fall risk older adults survived without a fall event over a 1 year period. Randomized, two group, four time point (over 1 year) clinical trial testing RENEW versus TRAD as part of a 3 month multi-component exercise fall reduction program (MCEFRP). Primary outcomes of mobility, balance confidence, muscle power output and cross sectional area were analyzed using mixed effects modeling. The secondary outcomes of days to fall and days to near-fall were analyzed using survival analysis. The MCEFRP did have an effect on fall risk factors considered reversible with exercise interventions though there was no differential effect of RENEW versus TRAD (p = 0.896) on mobility, balance confidence, muscle power and cross sectional area. There were also no group differences in the number of days survived without a fall (p = 0.565) or near-fall (p = 0.678). Despite 100% of participants having at least one fall in the year prior to the MCEFRP, however, after 3 months of exercise and 9 months of follow-up

We investigated the relationships between average gait speed collected with the 10 Meter Walk Test (Comfortable and Fast) and 6 Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10 Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r > 0.70, p < 0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p

Background Dopamine replacement medication has positive effects on existing motor skills for people with Parkinson disease (PD), but may have detrimental effects on the learning of motor skills necessary for effective rehabilitation according to the dopamine overdose hypothesis. Objectives This study aimed to determine whether dopamine replacement medication (i.e. levodopa) affects: learning of a novel upper extremity task, decrements in skill following withdrawal of practice, the rate of learning, and the transfer of movement skill to untrained upper extremity tasks compared to training “off” medication, in people with PD. Methods Participants with mild-moderate PD (Hoehn and Yahr stage 2) were randomized to train “on” (n = 12) or “off” (n = 11) levodopa medication. Participants practiced 10 blocks of five trials of a functional motor task with their non-dominant upper extremity over three consecutive days (acquisition period), followed by a single block of five trials two and nine days later. Participants were also assessed “on” levodopa with two transfer tasks (the nine-hole peg test and a functional dexterity task) prior to any practice and nine days after the end of the acquisition period. Results Participants who practiced “on” levodopa medication learned the upper extremity task to a greater extent that those who practiced “off” medication, as determined by retained performance two days after practice. Skill decrement and skill transfer were not significantly different between groups. Rate of learning was unable to be modelled in this sample. Conclusions Levodopa medication improved the learning of an upper extremity task in people with mild-moderate PD.