Mild traumatic brain injury (mTBI) often presents with symptoms of dizziness, headache, and brain fog. Prior work has linked these symptoms to impaired autonomic nervous system function and associated changes in cerebral blood flow after mTBI. Arterial baroreflex function is central to the regulation of cerebral perfusion—modulating heart rate (HR) and blood pressure (BP) in response to postural changes and daily activity—and thus, of particular interest in understanding symptoms resulting from head trauma. This study sought to characterize sympathetic and parasympathetic baroreflex function in individuals with mTBI (≤14 days post injury) using standardized autonomic testing, and to assess the relationship between autonomic impairment and symptom severity. Seventy participants (35 mTBI, 35 age- and sex-matched controls) completed symptom questionnaires and a standardized autonomic battery that included heart rate variability during deep breathing, Valsalva maneuver, and 10-min head-up tilt (HUT) testing with beat-to-beat HR and BP monitoring. Outcome measures included HR/BP variability (SD), along with low frequency (LF) and high frequency power during supine and HUT phases. LF power during HUT was designated as the primary outcome of interest. Correlation and regression analyses assessed the relationship between autonomic outcome measures and postconcussion related symptom severity scores (Rivermead Post-Concussion Symptom Questionnaire-13), while controlling for potential confounders. Group-wise comparisons revealed significantly lower HR and BP variability, as well as reduced LF power of mean BP during HUT in the mTBI cohort compared to controls ( p = 0.002); LF power of HR was also significantly lower in mTBI compared to controls ( p = 0.011). Associations between autonomic metrics and symptom severity scores were weak. Individuals with mTBI (≤14 days since injury) exhibited blunted sympathetic baroreflex responses to orthostatic challenge as well as reduced HR/BP variability. These findings suggest physiological impairment in sympathetic activation post-mTBI, which may contribute to stressor-response based clinical symptomatology, but does not fully explain global symptom burden. Future studies should employ domain-specific symptom assessments (e.g., differentiating orthostatic from vertiginous or proprioceptive dizziness) and targeted physiological testing to further elucidate these relationships.

INTRODUCTION:The Vestibular/Ocular Motor Screening (VOMS) was created as a brief clinical screening tool for identifying vestibular and ocular motor symptoms and impairments post-concussion. It was found to have predictive validity in correctly identifying concussed athletes from healthy controls. In 2018, the Military Acute Concussion Evaluation 2 (MACE2) replaced the original Military Acute Concussion Evaluation (MACE); the most prominent change between the MACE and MACE2 was the addition of the VOMS. Despite its adoption into military medicine, it is not known if the addition of the VOMS to the MACE2 is acutely helpful, and if it provides additional information for diagnosis, prognosis, and/or management. The purposes of this systematic review were: (1) to determine the utility of the VOMS in correctly identifying concussed individuals, particularly as it pertains to military medicine; (2) to explore the extent to which the VOMS can inform concussion prognosis; and (3) to establish the value of the VOMS as a measure for monitoring the evolution of symptoms throughout a service member's course of care. MATERIALS AND METHODS:A comprehensive search of PubMed was performed from January 1, 2014 through August 16, 2023. Articles were included if they researched concussion or a related health condition or healthy controls and administered the VOMS. Articles were excluded if they discussed health conditions other than concussion; did not administer the VOMS; or were written in languages other than English. The tools used to assess methodological quality and risk of bias varied according to study design. Articles were classified into three primary domains: diagnosis, prognosis, and/or rehabilitation/recovery over time. RESULTS:A total of 231 articles were retrieved and 3 were duplicates, leaving 228 articles for review. Of the 228 articles screened, 100 relevant full-text articles were assessed for eligibility. Fifty-nine articles met our inclusion and exclusion criteria while the other 41 articles were rejected. Thirty-two articles helped to inform diagnosis, 15 prognosis, and 16 rehabilitation/recovery over time. CONCLUSIONS:The VOMS had excellent internal consistency and moderate to good test-retest reliability; however, a false-positive rate of 21.9% was found. Most studies indicated that a positive VOMS was associated with a delayed recovery. Several studies indicated that VOMS scores improved with targeted, active interventions and/or a symptom-guided progressive return to activity. The greatest limitation was the paucity of published evidence in the military population. More research is needed on the use of the VOMS in service members.

OBJECTIVE:After mild traumatic brain injury (mTBI), autonomic nervous system dysfunction is thought to contribute to exercise intolerance and self-reported postconcussive symptoms (e.g. dizziness, lightheadedness, brain fog) but little has been done to establish this relationship in the literature. METHODS:Through recent literature review, it appears that few studies have assessed both autonomic function and exercise intolerance, and for those that have utilized varying methodologies making comparison across studies difficult. Some emerging research has identified potential impairment within the sympathetic nervous system after mTBI but no relationship between exercise tolerance testing and postconcussive symptoms has been established. CONCLUSION:For neuropsychologists, a physiologic understanding of the scope of autonomic dysfunction and appropriate assessment is vitally important, as autonomic nervous system impairment has the potential to impact sleep and mood, and subsequently cognitive function and mental health. When working in collaboration with other disciplines, referrals to exercise intolerance testing and laboratory based autonomic assessments may occur. However, given the lack of an established evidence, the use of exercise intolerance and/or related symptoms to clinically insinuate dysfunction of the autonomic nervous system function is likely premature, and a more thorough assessment of autonomic function via established batteries is more appropriate.

BackgroundPostural orthostatic tachycardia syndrome (POTS) is a chronic condition associated with a high symptom burden and decreased quality of life (QOL). Exercise is currently considered to be a first line non-pharmacological treatment for POTS. The purpose of this systematic review was to evaluate the impact of exercise on cardiovascular and patient-centered outcomes in patients with POTS.PurposeTo evaluate whether exercise benefits patients with POTS by synthesizing data from published clinical studies.MethodsElectronic databases, including Medline, Embase, CINAHL Complete, Cochrane CENTRAL, and others were searched and results were exported on May 2, 2023. Study inclusion: those that utilized an exercise program as an intervention for POTS and were conducted as experimental or quasi-experimental design. Exclusions: Non-English language papers and opinion-based/theoretical/non-empirical studies/case reports. Data extraction was based on Cochrane Handbook guidance and summarized according to Synthesis Without Meta-analysis (SWiM) guidelines; methodological quality and risk of bias was evaluated using the JBI Critical Appraisal tools. Standardized effects were calculated and summarized based on the direction of effect.ResultsSeven studies included in the final review are described in the data summary and synthesis. Improvements in heart rate were reported across all studies reviewed, while stroke volume and QOL improvements were also found. Notably, not all studies reported on the latter two outcomes. Methodological variability across studies precluded meta-analysis, and risk of bias was considered moderate-high in all but a single study.ConclusionWhile currently available evidence supports exercise as beneficial to QOL and cardiovascular features of POTS, we identified a major need for additional studies assessing the effect of exercise on symptom burden and daily function, including studies that consider patients with specific comorbidities that impact exercise tolerability and/or dosing.

CONTEXT:Wearable sensors are increasingly popular in concussion research because of their objective quantification of subtle balance deficits. However, normative data and minimal detectable change (MDC) values are necessary to serve as references for diagnostic use and tracking longitudinal recovery. OBJECTIVE:To identify normative and MDC values for instrumented static- and reactive-balance tests, an instrumented static mediolateral (ML) root mean square (RMS) sway standing balance assessment and the instrumented, modified push and release (I-mP&R), respectively. DESIGN:Cross-sectional study. SETTING:Clinical setting. PATIENTS OR OTHER PARTICIPANTS:Normative static ML RMS sway and I-mP&R data were collected on 377 (n = 184 female) healthy National Collegiate Athletic Association Division I athletes at the beginning of their competitive seasons. Test-retest data were collected in 36 healthy control athletes based on standard recovery timelines after concussion. MAIN OUTCOME MEASURE(S):Descriptive statistics, intraclass correlation coefficients (ICCs), and MDC values were calculated for primary outcomes of ML RMS sway in a static double-limb stance on firm ground and a foam block, and time to stability and latency from the I-mP&R in single- and dual-task conditions. RESULTS:Normative outcomes across static ML RMS sway and I-mP&R were sensitive to sex and type of footwear. Mediolateral RMS sway demonstrated moderate reliability in the firm condition (ICC = 0.73; MDC = 2.7 cm/s2) but poor reliability in the foam condition (ICC = 0.43; MDC = 11.1 cm/s2). Single- and dual-task times to stability from the I-mP&R exhibited good reliability (ICC = 0.84 and 0.80, respectively; MDC = 0.25 and 0.29 seconds, respectively). Latency from the I-mP&R had poor to moderate reliability (ICC = 0.38 and 0.55; MDC = 107 and 105 milliseconds). CONCLUSIONS:Sex-matched references should be used for instrumented static- and reactive-balance assessments. Footwear may explain variability in static ML RMS sway and time to stability of the I-mP&R. Moderate-to-good reliability suggests time to stability from the I-mP&R and ML RMS static sway on firm ground can be used for longitudinal assessments.

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.

Context Current clinical concussion evaluations assess balance deficits using static or dynamic balance tasks while largely ignoring reactive balance. Including a reactive balance assessment might provide a more comprehensive concussion evaluation. Objectives To identify redundancy in current clinical baseline assessments of concussion and determine whether reactive balance adds unique information to these evaluations. Design Cross-sectional study. Setting Clinical assessment. Patients or Other Participants A total of 279 healthy National Collegiate Athletic Association Division I athletes. Intervention(s) Two cohorts of data were collected at the beginning of the athletic season. For cohort 1 (n = 191), the Immediate Post-Concussion Assessment and Cognitive Tool, instrumented modified push and release (I-mP&R), and Balance Error Scoring System (BESS) were administered. For cohort 2 (n = 88), the I-mP&R, BESS, timed tandem gait, walking with eyes closed, and clinical reaction time were administered. Main Outcome Measure(s) The strengths of the relationships between the Immediate Post-Concussion Assessment and Cognitive Tool cognitive indices, mP&R clinical score, instrumented measures (BESS sway; I-mP&R time to stability, latency, and step length), BESS score, timed tandem gait, walking time to completion, and clinical reaction time were characterized. Results The strongest interinstrument correlation value was between single-task time to stability from the I-mP&R and clinical reaction time but was considered weak (r = 0.35, P = .001). The mP&R and I-mP&R clinical scores were weakly associated with the other assessments. Conclusions Weak correlations between interassessment variables indicated that little redundancy was present in the current clinical evaluations. Furthermore, reactive balance represents a unique domain of function that may improve the comprehensiveness of clinical assessments.

Exercise is a well-documented, nonpharmacologic treatment for individuals with autonomic dysfunction and associated orthostatic intolerance, such as postural tachycardia syndrome and related disorders. Exercise has been shown to increase blood volume, reverse cardiovascular deconditioning, and improve quality of life. Current first-line standard of care treatment for autonomic dysfunction combines graded approaches to exercise with medications and lifestyle modifications. However, current exercise rehabilitation protocols for postural orthostatic tachycardia syndrome contain rigid timelines and progression paradigms that often threaten tolerability and adherence. In addition, they fail to account for clinical variables potentially critical to care and lack guidance for individualization, limiting accessibility to patients with co-morbidities that affect exercise appropriateness and safety. Therefore, we introduce an adaptive approach to exercise prescription for orthostatic intolerance that allows patient-specific modifications to meet functional goals for a wider spectrum of patients, thus improving adherence. The proposed approach integrates iterative physiological and symptomatic assessments to provide flexible, yet structured, exposure to aerobic exercise and strength training to improve functional capacity and tolerance of daily activities for patients with postural tachycardia syndrome and related autonomic disorders.

Objective: This proof-of-concept study was to investigate the relationship between photobiomodulation (PBM) and neuromuscular control.Background: The effects of concussion and repetitive head acceleration events (RHAEs) are associated with decreased motor control and balance. Simultaneous intranasal and transcranial PBM (itPBM) is emerging as a possible treatment for cognitive and psychological sequelae of brain injury with evidence of remote effects on other body systems.Methods: In total, 43 (39 male) participants, age 18-69 years (mean, 49.5; SD, 14.45), with a self-reported history of concussive and/or RHAE and complaints of their related effects (e.g., mood dysregulation, impaired cognition, and poor sleep quality), completed baseline and posttreatment motor assessments including clinical reaction time, grip strength, grooved pegboard, and the Mini Balance Evaluation Systems Test (MiniBEST). In the 8-week interim, participants self-administered itPBM treatments by wearing a headset comprising four near-infrared light-emitting diodes (LED) and a near-infrared LED nasal clip.Results: Posttreatment group averages in reaction time, MiniBEST reactive control subscores, and bilateral grip strength significantly improved with effect sizes of g = 0.75, g = 0.63, g = 0.22 (dominant hand), and g = 0.34 (nondominant hand), respectively.Conclusion: This study provides a framework for more robust studies and suggests that itPBM may serve as a noninvasive solution for improved neuromuscular health.

ABSTRACT Objective This study aimed to assess common barriers to adherence to the Physical Therapy Concussion/Mild Traumatic Brain Injury Clinical Practice Guidelines (PTCPG) and design an action plan to address these barriers. Setting Single University Health System Participants Electronic medical record (EMR) data were collected over an initial 6-month period and then a follow-up 6-month period after the interventions. The initial period yielded an average of 129 patients with a concussion diagnosis, and the follow-up period yielded an average of 331 patients. Design Through the knowledge-to-action framework, it was identified that providers were often unaware of current practice guidelines, and some had a low comfort level with the diagnosis. Subsequent action items to address these barriers included education sessions, modification of a concussion documentation template to better align with PTCPG recommendations, and the design of a pop-up within the electronic medical records that allowed providers to create a referral to a concussion treatment network. Main Measures Frequency calculations were performed based on whether the outcome measure was performed at any time during a concussion episode of care. Selection of outcome measures was determined by what outcome measures were available for use within the EMR and aligned with the PTCPG recommended system domains. Data was collected from the following providers: physical therapists, occupational therapists, sports medicine physicians and physical medicine & rehab physicians. Results From the initial EMR query to the follow-up, the following increases in use of outcome measures were seen with each outcome measure, Post-Concussion Symptom Scale (PCSS) = 10.0%, Cervical & Thoracic Screen = 6.0%, Vestibular Ocular Motor Screen (VOMS) = 12.6%, Modified Orthostatic Vital Signs (MOVS) = 18.9%, Buffalo Concussion Treadmill Test (BCTT) = 3.5%, Balance Error Scoring System (BESS) = -4.8%, Sensory Organization Test (SOT) = 0.9%. Conclusion The improvement in adherence to recommendations was attributed to a knowledge to action approach that combined education along with structural changes to electronic medical record documentation.

Identifying risk factors for musculoskeletal 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 musculoskeletal injury than traditional tests alone.

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 ).

PURPOSE:Concussion commonly results in exercise intolerance, often limiting return to activities. Improved understanding of the underlying mechanisms of post-concussive exercise intolerance could help guide mechanism-directed rehabilitation approaches. Signs of altered cardiovascular autonomic regulation-a potential contributor to exercise intolerance-have been reported following concussion, although it is not clear how these findings inform underlying mechanisms of post-concussive symptoms. Systematic summarization and synthesis of prior work is needed to best understand current evidence, allowing identification of common themes and gaps requiring further study. The purpose of this review was to (1) summarize published data linking exercise intolerance to autonomic dysfunction, and (2) summarize key findings, highlighting opportunities for future investigation. METHODS:The protocol was developed a priori, and conducted in five stages; results were collated, summarized, and reported according to PRISMA guidelines. Studies including injuries classified as mild traumatic brain injury (mTBI)/concussion, regardless of mechanism of injury, were included. Studies were required to include both autonomic and exercise intolerance testing. Exclusion criteria included confounding central or peripheral nervous system dysfunction beyond those stemming from the concussion, animal model studies, and case reports. RESULTS:A total of 3116 publications were screened; 17 were included in the final review. CONCLUSION:There was wide variability in approach to autonomic/exercise tolerance testing, as well as inclusion criteria/testing timelines, which limited comparisons across studies. The reviewed studies support current clinical suspicion of autonomic dysfunction as an important component of exercise intolerance. However, the specific mechanisms of impairment and relationship to symptoms and recovery require additional investigation.

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.

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.

Abnormal balance is a common clinical sign of mild traumatic brain injury (mTBI). Despite the clinical utility of reactive balance testing in other balance impaired populations, current clinical testing for mTBI does not include reactive postural responses (RPR) which may be more representative of a competitive athletic environment.PURPOSE: To examine differences in RPR in athletes with mTBI compared to healthy controls at three time points: within 48 hours after mTBI (Acute), within 24 hours of beginning return-to-play protocol (PreRTP), within 24 hours of being cleared for full return to competition (PostRTP).METHODS: RPR in 24 collegiate athletes with mTBI (F = 12, age 19.42 ± 1.28 years, BMI 25.18 ± 3.38 kg/m2) and 19 healthy controls (F = 8, age 19.67 ± 1.56 years, BMI 24.36 ± 2.98 kg/m2) were assessed using the Push and Release, with eyes closed, under single (ST) and dual-task (DT; concurrent verbal cognitive task) conditions at three time points after-mTBI (acute, PreRTP, PostRTP). Inertial sensors on the sternum, lumbar, and feet were used to assess time to stabilization (TTS). A sensor on the tester’s hand determined release time. Standardized effect sizes, mean differences, and confidence intervals were calculated for each time point for both tasks. RESULTS: There was a median of six days between PreRTP and PostRTP. The mTBI group had longer ST TTS (1.09 ± 0.315 s) than healthy controls (0.904 ± 0.157 s) at the acute time point by 0.187 s (Cohen’s d (d) = 0.73; 95% CI: [0.179, 0.204]), at PreRTP by 0.069 s (d = 0.32; 95% CI: [0.053, 0.084]) and shorter TTS at PostRTP by 0.034 s (d = -0.166; 95%CI: [-0.048,-0.019]). The mTBI group had longer DT TTS (1.23 ± 0.31 s) than healthy controls (0.984 ± 0.207 s) at the acute time point by 0.248 s (d = 0.92; 95% CI: [0.230, 0.267]), at PreRTP by 0.035 s (d = 0.18 ;95% CI: [0.021, 0.048]) and at PostRTP by 0.036 s (d = 0 .18 ; 95%CI: [0.022, 0.050]). CONCLUSIONS: There was a large difference in RPR between athletes with mTBI and healthy controls at the acute time point for both ST and DT; athletes with mTBI had slower time to stabilization. Differences in RPR were small at PreRTP and PostRTP for both ST and DT. These preliminary results suggest that mTBI affects reactive postural responses acutely following mTBI but these responses recover over time. Supported by PAC 12 Student Athlete Health & Wellbeing

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 3 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 whether 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 4747 publications were identified, and a total of 3 studies (5 publications) were included in the review. CONCLUSION:The limited number of studies available on this topic highlights 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 3 classes of postural control in future research.