Exertional Tolerance Assessments After Mild Traumatic Brain Injury: A Systematic Review

Use of physical exertion to enhance objective testing following mild traumatic brain injury: a systematic review

Background

Assessment of recovery from mild traumatic brain injury (mTBI) is complex and challenging. Post-exertion testing, where individuals undergo objective testing following physical exercise, has shown promise in identifying mTBI-related impairments that may not be evident at rest, but could hinder a safe return to sport.

Objectives

To conduct a systematic review to determine if physical exertion affects objective physiological or sensorimotor tests differently in individuals with mTBI compared with healthy controls.

Methods

A systematic search of 11 databases and five trial registries on 30 May 2024 identified reports that: (i) compared individuals aged 12-65 years within 12 months of mTBI against healthy control participants, (ii) investigated the effects of a single session of physical exertion and (iii) collected before, during or after exertion, objective measures of physiological or sensorimotor function. Risk of bias was assessed with the Risk Of Bias In Non-randomized Studies of Interventions tool. Results were analysed descriptively.

Results

The review included 22 studies with 536 participants wih mTBI. Risk of bias was deemed high. At rest, 8/22 (36%) studies detected differences in physiological responses between participants wih mTBI and healthy control participants. During or after exertion, 21/22 (96%) studies detected differences in physiological responses, including cardiovascular, respiratory and cerebral autoregulation.

Conclusion

The findings indicate that objective testing during or after physical exertion can enhance the ability to detect mTBI-related impairments in various physiological parameters, and this concept could be considered when monitoring recovery and return to sport. Further studies are needed.

PROSPERO registration number

CRD42023411681.

An Exploratory Analysis of Physical Examination Subtypes in Pediatric Athletes With Concussion

OBJECTIVE

Pediatric athletes with concussion present with a variety of impairments on clinical assessment and require individualized treatment. The Buffalo Concussion Physical Examination is a brief, pertinent clinical assessment for individuals with concussion. The purpose of this study was to identify physical examination subtypes in pediatric athletes with concussion within 2 weeks of injury that are relevant to diagnosis and treatment.

DESIGN

Secondary analysis of a published cohort study and clinician consensus.

SETTING

Three university-affiliated sports medicine centers.

PARTICIPANTS

Two hundred seventy children (14.9 ± 1.9 years).

INDEPENDENT VARIABLES

Orthostatic intolerance, horizontal and vertical saccades, smooth pursuits, vestibulo-ocular reflex, near-point convergence, complex tandem gait, neck range of motion, neck tenderness, and neck spasm.

MAIN OUTCOME MEASURES

Correlations between independent variables were calculated, and network graphs were made. k -means and hierarchical clustering were used to identify clusters of impairments. Optimal number of clusters was assessed. Results were reviewed by experienced clinicians and consensus was reached on proposed subtypes.

RESULTS

Physical examination clusters overlapped with each other, and no optimal number of clusters was identified. Clinician consensus suggested 3 possible subtypes: (1) visio-vestibular (horizontal and vertical saccades, smooth pursuits, and vestibulo-ocular reflex), (2) cervicogenic (neck range of motion and spasm), and (3) autonomic/balance (orthostatic intolerance and complex tandem gait).

CONCLUSIONS

Although we identified 3 physical examination subtypes, it seemed that physical examination findings alone are not enough to define subtypes that are both statistically supported and clinically relevant, likely because they do not include symptoms, assessment of mood or cognitive problems, or graded exertion testing.

Does early exercise intolerance effect time to return to play, symptom burden, neurocognition, Vestibular-Ocular-Motor (VOM) function and academic ability in acutely concussed student-athletes?

INTRODUCTION

Early Exercise Intolerance (EEI) is associated with delayed recovery and longer time to Return To Play (RTP), but this has not been established.Participants; (n = 52, male n = 30) UK university-aged rugby-union student-athletes.

METHODS

Student-athletes completed baseline screening (July-October 2021 and 2022). The test battery was repeated within 48 h, 4, 8 and 14 days after a Sports-Related Concussion (SRC) with the Buffalo Concussion Bike or Treadmill Test to set sub-symptom heart rate threshold. Student-athletes then completed a controlled early exercise protocol in-between reassessment (days 3, 5-7 and 9-13). Those with EEI were compared to those with early-exercise tolerance.

OUTCOME MEASURES

Post-Concussion Symptom Scale, Immediate Post-Concussion and Cognitive Test, Vestibular-Ocular Motor Screening Tool and the Revised Perceived Academic Impact Tool.

RESULTS

EEI was seen throughout the initial 14-days post-SRC (23.8%, 22.4%, 25.5%. 25.0%). EEI was associated with a slower reaction time within 48 h (-0.01 (-0.030-0.043) Vs 0.06 (0.033-0.24), p = 0.004) and greater VOMS scores within 48 h; (0.00 (0.00-4.00) Vs 5.50 (2.75-9.00), p = 0.016) and 4 days (0.00 (0.00-2.00) Vs 5.00 (0.00-6.00), p = 0.044). RTP was 12.5 days longer in those with EEI at 14-days post-SRC.

CONCLUSION

EEI is prevalent following an SRC in university-aged student-athletes and was associated with delayed recovery and RTP.

Autonomic dysfunction and exercise intolerance in concussion: a scoping review

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.

Psychological Contributions to Symptom Provocation Testing After Concussion

OBJECTIVE

Following concussion, symptoms such as headache, dizziness, and fatigue may transiently worsen or reemerge with increased exertion or activity. Standardized tests have been developed to assess symptom increases following aerobic, cognitive, or vestibular/oculomotor challenge. Although neurophysiological mechanisms are proposed to underlie symptom increases following exertion, psychological factors such as anxiety and misinterpretation of normal bodily sensations may also play a role. In this study, we examined the contribution of psychological factors to symptom provocation testing outcomes.

SETTING

Two outpatient concussion clinics in British Columbia, Canada.

PARTICIPANTS

Adults with persistent symptoms following concussion ( N = 79; 62% women).

DESIGN

In a single session, participants completed self-report questionnaires measuring the psychological factors of interest and underwent symptom provocation testing including aerobic (Buffalo Concussion Bike Test; BCBT), cognitive (National Institutes of Health Toolbox-Cognition Battery; NIHTB-CB), and vestibular/oculomotor (Vestibular/Ocular Motor Screening for Concussion; VOMS) challenge.

MAIN MEASURES

Psychological factors of interest included premorbid and current anxiety (Generalized Anxiety Disorder-7; GAD-7), catastrophizing (Pain Catastrophizing Scale-Adapted; PCS-A), fear avoidance behavior (Fear Avoidance Behavior after Traumatic Brain Injury; FAB-TBI), and somatization (Patient Health Questionnaire-15; PHQ-15). Our primary outcome variables were self-reported symptom change during each symptom provocation test.

RESULTS

We found that current anxiety ( B = 0.034; 95% CI = 0.003, 0.065), symptom catastrophizing ( B = 0.013; 95% CI = 0.000, 0.026), fear avoidance behavior ( B = 0.029; 95% CI = 0.008, 0.050), and somatization ( B = 0.041; 95% CI = 0.007, 0.075) were associated with increased symptoms during the VOMS in univariate models adjusted for time postinjury but not in a multivariable model that included all covariates. The psychological variables of interest were not significantly related to symptom change during the BCBT or NIHTB-CB.

CONCLUSION

Our findings suggest that symptom provocation test failure should be interpreted with caution because it might indicate psychological maladjustment rather than lingering brain injury or incomplete neurophysiological recovery.

Examining how time from sport-related concussion to initial assessment predicts return-to-play clearance

OBJECTIVE

(i) To analyze data of adolescents who have sustained a sport-related concussion (SRC) through the use of Complete Concussion Management Inc. (CCMI) concussion database system; and (ii) to determine an optimal time to assess and manage an athlete with an SRC by prospectively analyzing data from CCMI concussion database system.

METHOD

A cohort of patients, ages 8-18 years, who sustained an SRC, assessed 30 days or less from injury and were treated at partnered CCMI clinics across Canada were prospectively followed. The primary outcome measure was recovery, defined as CCMI discharge, which includes an athlete having completed all return-to-school and return-to-play steps and passed the Gapski-Goodman test without symptom exacerbation.

RESULTS

1213 athletes (482 female) were included for analysis. Days between injury and initial assessment (p = 0.00), male sex (p = 0.00), and previous concussion history (p = 0.00) were significant predictors of time to discharge. A log-rank test revealed a significant difference (p = 0.00) in time to discharge with athletes assessed <10 days of injury discharged at a mean of 23.5 days (95% CI, 22.5, 24.5) and those assessed at day 10 to 30 were discharged at a mean of 37.1 days (95% CI, 33.7, 40.5). Athletes who were assessed at 0 to 9 days from injury were two times more likely to be discharged sooner compared to those athletes assessed 10 to 30 days from injury (HR 2.03, p = 0.00).

CONCLUSION

Time from SRC to initial assessment significantly predicted time to discharge, with those being evaluated earlier experiencing a faster discharge. The results aid in establishing recommended timelines for evaluation following an SRC in order to prevent or mitigate athletes experiencing a prolonged recovery and encourage timely access to care and a quicker return to life post-concussive injury.

Clinical application of the Buffalo Concussion Treadmill Test and the Buffalo Concussion Bike Test: A systematic review

Objective

To identify and synthesise research evidence regarding psychometric properties and clinical utility of the Buffalo Concussion Treadmill Test (BCTT) and Buffalo Concussion Bike Test (BCBT) for use with patients with acute concussion, post-concussion syndrome (PCS) or physiological post-concussion disorder (PPCD).

Data sources

ProQuest (ProQuest Central), PEDro, Medline (Ovid), Emcare (Ovid), EBSCOhost (Health collection) and Google Scholar, searched September 8th-12th, 2020.

Study selection

Two authors independently selected studies that met eligibility criteria. Studies were selected if they were original research of any design, that investigated the properties of the testing protocols in either concussed or uninjured participants. Articles not published in English, that were not original research or that used significantly different testing protocols were excluded. The search yielded 250 articles, 11 of which were eligible and included in this review.

Data extraction

Included studies were critically appraised independently by two authors, using the Mixed Methods Appraisal Tool (MMAT). Data relating to study characteristics and key findings were extracted from the studies, documented in tables, and used to inform a critical narrative synthesis of findings.

Data synthesis

To provide recommendations relating to each aim of the review, a strength of evidence scoring system was used. Available evidence supported use of the BCTT, with strong evidence supporting the safety and construct validity of the test and moderate evidence supporting its prognostic value. There has been very limited research investigating use of the BCBT.

Conclusion

The findings support a recommendation for use of the BCTT in clinical settings for management of acute concussion, PCS and PPCD. There is limited evidence available for the BCBT. Additional studies are needed of both tests to further establish their clinical value.

A pilot study on exertional tasks with physiological measures designed for the assessment of military concussion

Background:

Guidelines for clinicians treating military concussion recommend exertional testing before return-to-duty, yet there is currently no standardized task or inclusion of an objective physiological measure like heart rate variability (HRV).

Methodology & results:

We pilot-tested two clinically feasible exertional tasks that include HRV measures and examined reliability of a commercially available heart rate monitor. Testing healthy participants confirmed that the 6-min step test and 2-min pushup test evoked the targeted physiological response, and the Polar H10 was reliable to the gold-standard electrocardiogram.

Conclusion:

Both tasks are brief assessments that can be implemented into primary care setting including the Polar H10 as an affordable way to access HRV. Additional research utilizing these tasks to evaluate concussion recovery can validate standardized exertional tasks for clinical use.

Assessing Physical Function and Mobility following Pediatric Traumatic Brain Injury with the NIH Toolbox Motor Battery: A Feasibility Study

AIMS

Traumatic brain injury (TBI) can impair physical function in children. The NIH Toolbox Motor Battery (NIHTB-M) was designed to be a brief assessment of physical function, but no studies have examined its use in children with TBI. This study aims to describe the feasibility of using the NIHTB-M to assess children with TBI.

METHODS

The NIHTB-M was administered to children with TBI 2 weeks (n = 22) and/or 6 months (n = 23) following injury. This descriptive study summarizes participant performance, administration challenges, and the association between NIHTB-M scores, participant characteristics, and subjective report of physical function.

RESULTS

Of the NIHTB-M domains, deficits in endurance and balance were most prevalent. Children aged 5 to 16 years could complete the assessment per administration guidelines, except for a few cases (n = 3) where orthopedic injuries limited participation. Younger children (aged 3 to 4) had difficulty following the NIHTB-M directions. Technological issues impacted balance assessment in several cases (n = 6).

CONCLUSION

The NIHTB-M is brief to administer, generally well tolerated by school-aged children and, despite occasional technological challenges, is a feasible performance-based battery for assessment of children with TBI for clinical and research purposes. Additional investigation of psychometric properties and ceiling and floor effects is needed.

Physical Therapy Evaluation and Treatment After Concussion/Mild Traumatic Brain Injury

Over the last decade, numerous concussion evidence-based clinical practice guidelines (CPGs), consensus statements, and clinical guidance documents have been published. These documents have typically focused on the diagnosis of concussion and medical management of individuals post concussion, but provide little specific guidance for physical therapy management of concussion and its associated impairments. Further, many of these guidance documents have targeted specific populations in specific care contexts. The primary purpose of this CPG is to provide a set of evidence-based recommendations for physical therapist management of the wide spectrum of patients who have experienced a concussive event. J Orthop Sports Phys Ther 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301.

Association of Simple Step Test With Readiness for Exercise in Youth After Concussion

OBJECTIVES

We hypothesized that a submaximal step test would be associated with readiness to commence graded exercise in children and adolescents with concussion.

METHODS

Children and adolescents aged 8 to 18 years performed standard concussion clinical assessment for vestibular/ocular and balance impairment, and exercise examination utilizing the 3-minute Kasch Pulse Recovery test (KPR) and a symptom-limited graded exercise test (GXT). Outcome measures included activity readiness and symptom exacerbation.

RESULTS

Forty-five participants (mean age 13.2 ± 2.1 years, 76% male) had a confirmed concussion (73% sports-related). Some participants required follow-up testing giving 75 clinical presentations. Sensitivity and specificity of the KPR were 100% and 95.7%, respectively. Area under the receiver operating characteristics curve was 0.979. Activity readiness to GXT and KPR was strongly associated (χ = 21.672, P < .001), while symptom exacerbation showed a significant correlation between testing methods (r = 0.796, P < .001). Better exercise performance on GXT and KPR was significantly correlated with normal Vestibular/Ocular Motor Screening (rs = -0.380, P = .010, and rs = -0.281, P = .017, respectively) and Modified Balance Error Scoring System (rs = -0.452, P < .001, and rs = -0.301, P = .010, respectively).

CONCLUSION

The KPR is a simple and practical tool to determine whether it is appropriate for a child or adolescent with concussion to commence graded exercise.

Review of the Management of Pediatric Post-Concussion Syndrome-a Multi-Disciplinary, Individualized Approach

PURPOSE OF REVIEW

Post-concussion syndrome (PCS), when the patient's concussion symptoms last longer than 4-6 weeks, affects 10-30% of concussion patients. PCS presents a significant source of morbidity to patients and a management challenge to providers. In this review, we present the current evidence and best management approaches for pediatric PCS.

RECENT FINDINGS

There is limited high-quality evidence in pediatric PCS. There is some evidence supporting pharmaceutical management of post-traumatic headaches, cognitive symptoms, and emotional symptoms. Vestibular-ocular dysfunction should be evaluated and managed appropriately. Neuropsychological recovery is expected, but requires appropriate attention to Return to Learn. Emotional symptoms are common in PCS and the evidence supports treatment with cognitive behavioral therapy. PCS presents a unique therapeutic challenge affecting multiple domains for patients-physical, sleep, cognitive, and emotional. Successful management of PCS requires a multi-disciplinary and individualized approach. There remains a significant need for further research, specifically looking into the outcomes and effective interventions in pediatric PCS.

Active recovery from concussion

PURPOSE OF REVIEW

Recent studies are challenging the utility of prolonged rest as treatment for concussion and postconcussion syndrome (PCS). The purpose of this paper is to review the evidence for active recovery from concussion and PCS.

RECENT FINDINGS

Emerging data identify the central role of autonomic nervous system (ANS) dysfunction in concussion pathophysiology. The exercise intolerance demonstrated by athletes after sport-related concussion may be related to abnormal ANS regulation of cerebral blood flow. As aerobic exercise training improves ANS function, sub-symptom threshold exercise treatment is potentially therapeutic for concussion. A systematic assessment of exercise tolerance using the Buffalo Concussion Treadmill Test has been safely employed to prescribe a progressive, individualized subthreshold aerobic exercise treatment program that can return patients to sport and work. Multiple studies are demonstrating the efficacy of an active approach to concussion management.

SUMMARY

Sustained rest from all activities after concussion, so-called 'cocoon therapy', is not beneficial to recovery. Evidence supports the safety, tolerability, and efficacy of controlled sub-symptom threshold aerobic exercise treatment for PCS patients. Further study should determine the efficacy and optimal timing, dose, and duration of subthreshold aerobic exercise treatment acutely after concussion because early intervention has potential to prevent PCS.