The Role of Aerobic Exercise in Reducing Persistent Sport-related Concussion Symptoms

Concussion and the Autonomic, Immune, and Endocrine Systems: An Introduction to the Field and a Treatment Framework for Persisting Symptoms

A significant proportion of patients who sustain a concussion/mild traumatic brain injury endorse persisting, lingering symptoms. The symptoms associated with concussion are nonspecific, and many other medical conditions present with similar symptoms. Medical conditions that overlap symptomatically with concussion include anxiety, depression, insomnia, chronic pain, chronic fatigue, fibromyalgia, and cervical strain injuries. One of the factors that may account for these similarities is that these conditions all present with disturbances in the optimal functioning of the autonomic nervous system and its intricate interactions with the endocrine system and immune system-the three primary regulatory systems in the body. When clinicians are working with patients presenting with persisting symptoms after concussion, evidence-based treatment options drawn from the literature are limited. We present a framework for the assessment and treatment of persisting symptoms following concussion based on the available evidence (treatment trials), neuroanatomical principles (research into the physiology of concussion), and clinical judgment. We review the research supporting the premise that behavioral interventions designed to stabilize and optimize regulatory systems in the body following injury have the potential to reduce symptoms and improve functioning in patients. Foundational concussion rehabilitation strategies in the areas of sleep stabilization, fatigue management, physical exercise, nutrition, relaxation protocols, and behavioral activation are outlined along with practical strategies for implementing intervention modules with patients.

Identifying the Cerebral Physiologic Response to Aerobic Exercise Following Concussion: A Scoping Review

OBJECTIVE

The purpose of this study was to identify the cerebral physiologic response to aerobic exercise in individuals with a symptomatic concussion, highlighting available knowledge and knowledge gaps in the literature.

DESIGN

A systematic scoping review was conducted and reported in keeping with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. A search of EMBASE, MEDLINE, SCOPUS, BIOSIS, and Cochrane libraries was conducted on June 15, 2023 (from database inception). An online systematic/scoping review management system was used to remove duplicates, and the remaining articles were screened for inclusion by 2 researchers. Inclusion criteria required articles to be original research published in peer-reviewed journals. Additionally, studies were required to have an aerobic exercise component, include a measure of cerebral physiology during a bout of aerobic exercise, exclude moderate and/or severe traumatic brain injury (TBI) populations, and be in the English language. Both human and animal studies were included, with participants of any age who were diagnosed with a mild TBI/concussion only (ie, Glasgow Coma Scale score ≥ 13). Studies could be of any design as long as a measure of cerebral physiologic response to a bout of aerobic exercise was included.

RESULTS

The search resulted in 1773 articles to be screened and data from 3 eligible studies were extracted.

CONCLUSIONS

There are currently too few studies investigating the cerebral physiologic response to aerobic exercise following concussion or mild TBI to draw definitive conclusions. Further research on this topic is necessary since understanding the cerebral physiologic response to aerobic exercise in the concussion and mild TBI populations could assist in optimizing exercise-based treatment prescription and identifying other targeted therapies.

Response of Central Nervous System Biomolecules and Systemic Biomarkers to Aerobic Exercise Following Concussion: A Scoping Review of Human and Animal Research

The purpose of this study was to identify the response of biomolecules and biomarkers that are associated with the central nervous system to aerobic exercise in human and pre-clinical models of concussion or mild traumatic brain injury (TBI), and to highlight the knowledge gaps in the literature. A systematic scoping review was conducted following a search of EMBASE, MEDLINE, SCOPUS, BIOSIS, and Cochrane Libraries performed on September 8, 2023 (from data base inception). The scoping review was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Duplicates were removed and article screening was performed using an online systematic review management system. The search resulted in a total of 2,449 articles being identified, with 14 articles meeting the inclusion/exclusion criteria and having their data extracted. One study was conducted in humans, while the remainder of identified studies utilized murine models. The current literature is limited and evaluated many different biomolecules and biomarkers with brain-derived neurotrophic factor being the most researched. Further studies on this topic are needed to better understand the biomarker response to exercise after concussion and mild TBI, especially in the human population.

Exercising More Than 150 min/wk After Concussion Is Associated With Sleep Quality Improvements

OBJECTIVE

To examine whether a high volume of aerobic exercise after concussion (>150 min/wk) is associated with improved sleep quality over a 1-month period. We hypothesized that more than 150 min/wk of exercise would be associated with improved sleep quality across concussion recovery.

DESIGN

Prospective cohort observational study.

SETTING

Sports medicine clinic.

PARTICIPANTS

Adolescents initially tested 8.4 ± 3.5 (range, 2-18) days postconcussion who returned for a follow-up assessment 34.3 ± 7.7 (range: 20-49) days postconcussion.

MAIN OUTCOME MEASURES

Participants completed the Pittsburgh Sleep Quality Index and the Post-Concussion Symptom Inventory. No specific exercise or sleep recommendations were given beyond what their treating physician provided. Between study visits, participants recorded exercise performed via wrist-worn actigraphy. We calculated average exercise minutes per week and grouped participants as those who exercised more than 150 min/wk versus those who exercised 150 min/wk or less.

RESULTS

Thirty-six adolescents participated. Fifteen (42%) recorded more than 150 min/wk of aerobic exercise (age = 14.0 ± 1.7 years; 47% female; mean = 5.6 ± 1.2 d/wk of exercise; mean = 49.2 ± 17.5 min/session), and 21 recorded 150 min/wk or less of aerobic exercise (age = 15.0 ± 1.9 years; 76% female; mean = 2.7 ± 1.6 d/wk of exercise; mean = 30.2 ± 7.8 min/session). There were no significant group differences in the proportion of those who self-reported beginning physical activity prior to enrollment (47% vs 33%; P = .42) or for initial sleep quality rating (8.0 ± 3.7 vs 8.6 ± 4.1; P = .67) or initial concussion symptom severity rating (34.9 ± 28.0 vs 42.6 ± 25.9; P = .40). The group that exercised more than 150 min/wk between visits demonstrated significantly greater median PSQI rating improvements than those who exercised 150 min/wk or less, with a large effect size noted (median change [interquartile range] = 5 [3, 7] vs 1 [0, 4]; P = .008; Cohen d = 0.96).

CONCLUSION

Current recommendations suggest that subsymptom aerobic exercise can be beneficial after concussion. Our findings indicate that an exercise volume of more than 150 min/wk led to greater sleep quality improvements than those who exercised below this level.

Concussion symptom presentation and clinical recovery among pediatric athletes: comparing concussions sustained during school and summer months

OBJECTIVE

We examined post-concussion symptom presentation, exercise, and sleep among pediatric athletes who sustained concussion during the school year vs. summer months.

METHODS

We evaluated athletes 6-18 years old within 21-days of concussion. They reported symptoms (Health and Behavior Inventory), with cognitive/somatic domain sub-scores calculated, and indicated if they had exercised or experienced sleep problems since injury. We grouped patients by injury season: summer months (June-August) vs. school year (September-May).

RESULTS

350 patients (14.4 ± 2.4 years old; 37% female; initial visit 8.8 ± 5.3 days post-concussion) were seen for care: 24% sustained a concussion during summer months, 76% during the school year. Lower cognitive (median = 7 [IQR = 1, 15] vs. 9.5 [4, 17]; p = 0.01), but not somatic (7 [2.5, 11] vs. 8 [4, 13]; p = 0.06), HBI scores were observed for patients injured during the summer. Groups were similar in proportion exercising (16% vs 17%) and endorsing sleep problems (29% vs 31%). After adjustments, sustaining a concussion during the summer predicted total (β=-3.43; 95%CI = -6.50, -0.36; p = 0.029) and cognitive (β = -2.29; 95%CI = -4.22, -0.36; p = 0.02), but not somatic (β=-1.46; 95%CI = -2.84, -0.08; p = 0.04), symptom severity.

CONCLUSION

Pediatric patients with concussion may present with greater cognitive symptoms during the school year, compared to summer months.

Factors Associated with Symptom Resolution after Aerobic Exercise Intervention in Adolescent and Young Adults with Concussion

BACKGROUND

Aerobic exercise facilitates postconcussion symptom resolution at the group level, but patient-level characteristics may affect the likelihood of treatment efficacy.

PURPOSE

This study aimed to investigate demographic and clinical characteristics, which differentiate postconcussion aerobic exercise treatment efficacy from nonefficacy in the intervention arm of a randomized clinical trial.

METHODS

Adolescent and young adult participants initiated a standardized aerobic exercise intervention within 14 d of concussion, consisting of self-selected exercise for 100 min·wk -1 at an individualized heart rate (80% of heart rate induced symptom exacerbation during graded exercise testing). Treatment efficacy was defined as symptom resolution within 28-d postconcussion. Treatment efficacy and nonefficacy groups were compared on demographics, clinical characteristics, intervention adherence, and persistent symptom risk using the Predicting Persistent Postconcussive Problems in Pediatrics (5P) clinical risk score.

RESULTS

A total of 27 participants (16.1 ± 2.3 yr old; range, 11-21 yr; 52% female) began the intervention, with a mean of 9.5 ± 3.7 d after concussion; half ( n = 13; 48%) demonstrated treatment efficacy (symptom resolution within 28 d postconcussion). Those whose symptoms resolved within 28 d had significantly lower preintervention postconcussion symptom inventory scores (21.2 ± 13.2 vs 41.4 ± 22.2; P < 0.01), greater adherence to the intervention (77% vs 36%; P = 0.05), and longer average exercise duration (median [interquartile range], 49.7 [36.8-68.6] vs 30.4 [20.7-34.7] min; P < 0.01) than those whose symptoms lasted more than 28 d. Groups were similar in age, sex, timing of intervention, and preintervention 5P risk score.

CONCLUSIONS

A standardized aerobic exercise intervention initiated within 14 d of concussion demonstrated efficacy for approximately half of participants, according to our definition of treatment efficacy. This multisite aerobic exercise intervention suggests that lower symptom severity, higher intervention adherence, and greater exercise duration are factors that increase the likelihood of symptoms resolving within 28 d of concussion.

Postconcussion Moderate to Vigorous Physical Activity Predicts Anxiety Severity among Adolescent Athletes

PURPOSE

This study aimed to examine how moderate-to-vigorous physical activity (MVPA) during concussion recovery influences self-reported anxiety symptoms at follow-up assessment. We hypothesized that more MVPA after concussion would be associated with lower anxiety rating at follow-up.

METHODS

We performed a prospective study of participants aged 13-18 yr initially assessed within 14 d of diagnosed concussion. Participants rated concussion symptoms using the Post-Concussion Symptom Inventory and were provided a wrist-worn actigraphy device to track activity for 1 wk after assessment. At follow-up assessment, participants rated anxiety symptoms using the four-question Patient-Reported Outcomes Measurement Information System (PROMIS) anxiety subscale. Each question ranged from 1 (never) to 5 (almost always), with an overall score range of 4-20. For univariable analysis, we calculated correlation coefficients between MVPA and PROMIS anxiety subscale scores. We then created a multiple linear regression model with follow-up PROMIS anxiety subscale score as the outcome and MVPA, sex, initial symptom severity, and preconcussion anxiety as predictors.

RESULTS

We enrolled and initially tested 55 participants, and 48 were included in the final analysis (age, 14.6±2.7 yr; 56% female; initial assessment, 7.3± 3.1 d; follow-up assessment, 42.0±29.7 d). We observed an inverse and low correlation between MVPA and follow-up PROMIS anxiety subscale T-scores ( r = -0.30, P = 0.04). Multivariable regression results indicated that MVPA ( β = -5.30; 95% confidence interval (CI), -10.58 to -0.01), initial Post-Concussion Symptom Inventory score ( β = 0.11; 95% CI, 0.03 to 0.19), and preconcussion anxiety ( β = 5.56; 95% CI, 0.12 to 11.0), but not sex ( β = -2.60; 95% CI, -7.14, to 1.94), were associated with follow-up PROMIS anxiety subscale T-scores.

CONCLUSIONS

After adjusting for covariates, more MVPA early after concussion predicted lower PROMIS anxiety subscale scores at follow-up. Although initial concussion symptom severity and preconcussion anxiety were also associated with follow-up PROMIS anxiety subscale score, MVPA represents a modifiable factor that may contribute to lower anxiety symptoms.

Brain changes: aerobic exercise for traumatic brain injury rehabilitation

Introduction

Traumatic Brain Injury (TBI) accounts for millions of hospitalizations and deaths worldwide. Aerobic exercise is an easily implementable, non-pharmacological intervention to treat TBI, however, there are no clear guidelines for how to best implement aerobic exercise treatment for TBI survivors across age and injury severity.

Methods

We conducted a PRISMA-ScR to examine research on exercise interventions following TBI in children, youth and adults, spanning mild to severe TBI. Three electronic databases (PubMed, PsycInfo, and Web of Science) were searched systematically by two authors, using keywords delineated from "Traumatic Brain Injury," "Aerobic Exercise," and "Intervention."

Results

Of the 415 papers originally identified from the search terms, 54 papers met the inclusion criteria and were included in this review. The papers were first grouped by participants' injury severity, and subdivided based on age at intervention, and time since injury where appropriate.

Discussion

Aerobic exercise is a promising intervention for adolescent and adult TBI survivors, regardless of injury severity. However, research examining the benefits of post-injury aerobic exercise for children and older adults is lacking.

Exercise Parameters for Postconcussion Symptom Rehabilitation: A Systematic Review

CONTEXT

Exercise rehabilitation for postconcussion symptoms (PCS) has shown some benefits in adolescent athletes; but a synthesis of evidence on exercise per se has been lacking.

OBJECTIVE

This systematic review aimed to determine if unimodal exercise interventions are useful to treat PCS and if so, to identify a set of clearly defined and effective exercise parameters for further research.

EVIDENCE ACQUISITION

Relevant health databases and clinical trial registries were searched from inception to June 2022. The searches used a combination of subject headings and keywords related to mild traumatic brain injury (mTBI), PCSs, and exercise. Two independent reviewers screened and appraised the literature. The Cochrane Collaboration's Risk of Bias-2 tool for randomized controlled trials was used to assess methodological quality of studies.

EVIDENCE SYNTHESIS

Seven studies were included in the review. Four studies were assessed to have a low overall risk of bias, 2 with low risk and 1 with some concerns. Participants in the studies comprised mostly adolescents with sports-related concussion. The review found exercise to be more beneficial than control conditions in 2 studies investigating acute PCS and 2 studies investigating persistent PCS. Within-group differences showing symptom improvement over time were observed in all 7 studies. In general, the review found support for programmatic exercise that commences after an initial period of rest for 24 to 48 hours. Recommendations for exercise parameters that can be explored in subsequent research include progressive aerobic exercise starting from 10 to 15 minutes at least 4 times a week, at a starting intensity of 50% HR of the subsymptom threshold, with length of program depending on recovery.

CONCLUSION

The evidence in support of exercise rehabilitation for PCSs is moderate based on the small pool of eligible studies. Further research can be guided by the exercise parameters identified in this review.

Efficacy of aerobic exercise following concussion: a narrative review

Concussion is a type of mild traumatic brain injury which results in symptoms within the physical, cognitive, emotional, and sleep domains. Historically, guidelines established by expert opinion have recommended rest during the initial stages of recovery following a concussion until symptom resolution. However, recent recommendations have shifted to advise an initial period of 24-48 h of rest immediately following concussion with the gradual introduction of light-to-moderate intensity aerobic exercise thereafter. Given the relatively recent transition in recommendations, the aim of this review is to provide an overview of the current literature on the efficacy of aerobic exercise following concussion. The current literature is limited to studies assessing the impact of standardized aerobic exercise following concussion. Upon review, literature suggests participating in aerobic exercise below the point of symptom exacerbation is safe in both the acute and chronic post-concussion symptom stages of recovery and does not delay time to medical clearance. Future large-scale randomized controlled trials assessing the impact of aerobic exercise and differences between males and females would help support the current evidence suggesting aerobic exercise could improve time to recovery following concussion and identify any sex differences in response. As well, future studies with the purpose of identifying optimal aerobic exercise volume and intensity in the treatment of concussion could improve the specificity of the current guidelines.

SWOT analysis of a physical activity intervention delivered to outpatient adults with a mild traumatic brain injury

Objectives

Physical activity interventions are effective to reduce the symptoms and recovery time after a mild traumatic brain injury; such interventions are not always embedded in all interdisciplinary outpatient settings. Service providers of a specialized rehabilitation program recognized the need to implement emerging evidence-based approaches to improve physical activity delivery. Understanding the perceptions of managers, clinicians, and users regarding the strengths, weaknesses, opportunities, and threats of the current physical activity intervention delivered to outpatient adults with a mild traumatic brain injury could inform local and widespread intervention development, enhancement, and implementation of evidence-based physical activity interventions.

Methods

This study used a descriptive qualitative design using a strength, weakness, opportunity, and threat analysis framework. Managerial staff (n = 3), clinicians (n = 6), and program users (n = 5) with persisting symptoms following a mild traumatic brain injury from an outpatient specialized public rehabilitation program in Québec (Canada) participated. Individual semi-structured interviews were performed, recorded, transcribed verbatim, and analyzed using a qualitative content analysis approach.

Results

Participants were generally positive about the intervention but expressed that improvement was required. Strengths (n = 15), weaknesses (n = 17), opportunities (n = 12), and threats (n = 6) related to eight overarching categories: physical activity intervention, health-related outcomes, clinical expertise, knowledge translation, communication, user engagement, resources, and accessibility. Category descriptions, convergent and divergent perspectives, and salient quotes of participants are provided.

Conclusions

Participants were generally positive about the intervention (e.g., format) but identified weaknesses (e.g., need for service providers to better describe the physical activity intervention using theoretically driven approaches). Consultations of stakeholders will inform future intervention enhancement efforts and assist in ensuring interventions meet user needs.

Sports-Related Concussions in Adults Presenting to Canadian Emergency Departments

OBJECTIVE

To document the occurrence and recovery outcomes of sports-related concussions (SRCs) presenting to the Emergency Department (ED) in a community-based sample.

DESIGN

A prospective observational cohort study was conducted in 3 Canadian hospitals.

SETTING

Emergency Department.

PATIENTS

Adults (≥17 years) presenting with a concussion to participating EDs with a Glasgow Coma Scale score ≥13 were recruited.

INTERVENTIONS

Patient demographics (eg, age and sex), clinical characteristics (eg, history of depression or anxiety), injury characteristics (eg, injury mechanisms and loss of consciousness and duration), and ED management and outcomes (eg, imaging, consultations, and ED length of stay) were collected.

MAIN OUTCOME MEASURES

Patients' self-reported persistent concussion symptoms, return to physical activity status, and health-related quality of life at 30 and 90 days after ED discharge.

RESULTS

Overall, 248 patients were enrolled, and 25% had a SRC. Patients with SRCs were younger and reported more physical activity before the event. Although most of the patients with SRCs returned to their normal physical activities at 30 days, postconcussive symptoms persisted in 40% at 90 days of follow-up. After adjustment, there was no significant association between SRCs and persistent symptoms; however, patients with concussion from motor vehicle collisions were more likely to have persistent symptoms.

CONCLUSION

Although physically active individuals may recover faster after a concussion, patients returning to their physical activities before full resolution of symptoms are at higher risk of persistent symptoms and further injury. Patient-clinician communications and tailored recommendations should be encouraged to guide appropriate acute management of concussions.

Postconcussion Dizziness Severity Predicts Daily Step Count during Recovery among Adolescent Athletes

PURPOSE

Physical activity (PA) after concussion is an important aspect of appropriate clinical management. However, symptoms or functional deficits may reduce patient propensity toward PA, thereby negatively affecting recovery. Our purpose was to examine whether postconcussion dizziness, total symptom severity, or postural stability predicts PA level in the 2 wk after initial evaluation.

METHODS

We evaluated adolescent athletes within 14 d of concussion on assessments of symptoms, dizziness, and postural stability. Athletes were provided an activity monitor to track PA for 2 wk after the evaluation. Our primary outcome was step count (mean steps per day). Potential predictor variables included sex, Post-Concussion Symptom Inventory (PCSI) total symptom severity, individual PCSI ratings of dizziness and balance impairment, and postural stability assessments (single- and dual-task tandem gait, modified Balance Error Scoring System). To examine predictors of PA, we calculated correlation coefficients between steps per day and each potential predictor and included significantly correlated variables in a multivariable regression model.

RESULTS

Participants were ages 12-18 yr (n = 35, 15.2 ± 1.7 yr, 49% female) and initially evaluated 7.3 ± 3.0 d after concussion. Upon univariable evaluation, PCSI dizziness rating (Pearson R = -0.49, P = 0.003) and sex (mean difference, 2449 steps per day; P = 0.05) were associated with steps per day. Within the multivariable regression analysis, PCSI dizziness rating (β = -1035; 95% confidence interval, -191 to -1880; P = 0.018), but not sex, predicted average steps per day in the 2 wk after initial evaluation.

CONCLUSIONS

Self-reported dizziness, but not overall symptom severity or postural stability, assessed within 14 d of concussion predicted daily step count in the subsequent 2 wk. Given the importance of PA for concussion recovery, treating acute postconcussion dizziness can potentially reduce a barrier to PA and improve recovery trajectories.

Recovery of symptoms, neurocognitive and vestibular-ocular-motor function and academic ability after sports-related concussion (SRC) in university-aged student-athletes: a systematic review

BACKGROUND

Physiological differences between a maturing and matured brain alters how Sports-Related Concussion (SRC) affects different age groups; therefore, a review specific to university-aged student-athletes is needed.

OBJECTIVES

Determine time to recovery for symptom burden, neurocognitive and Vestibular-Ocular-Motor (VOM) function and academic impact in university-aged student-athletes.

METHODS

Searches were conducted in PubMed, SpringerLink, PsycINFO, Science Direct, Scopus, Cochrane, Web of Science and EMBASE. Articles were included if they contained original data collected within 30 days in university-aged student-athletes, analysed SRC associated symptoms, neurocognitive or VOM function or academic ability and published in English. Two reviewers independently reviewed sources, using the Oxford Classification of Evidence-Based Medicine (CEBM) and the Downs and Black checklist, and independently extracting data before achieving consensus.

RESULTS

58 articles met the inclusion criteria. Recovery of symptoms occurred by 7 and 3-5.3 days for neurocognition. The evidence base did not allow for a conclusion on recovery time for VOM function or academic ability. Few papers investigated recovery times at specified re-assessment time-points and have used vastly differing methodologies.

CONCLUSIONS

To fully understand the implication of SRC on the university-aged student-athlete' studies using a multi-faceted approach at specific re-assessments time points are required.Systematic review registration number: CRD42019130685.

Physical Activity Following Sport-Related Concussion in Adolescents: A Systematic Review

OBJECTIVE

To evaluate the evidence related to how physical activity (PA) affects recovery following a sport-related concussion (SRC) in adolescents.

DESIGN

Systematic review Data Source: PUBMED, MEDLINE, and SPORTDiscus Eligibility criteria for selecting study:(1) original research article (e.g., randomized controlled trials (RCT), quasi-experimental designs, cohort, case-control studies), (2) 66% or greater of the sample has to have a SRC diagnosed by a clinician, (4) human research, (5) evaluate the effect of a SRC on PA in adolescents only (<18 years). Participants were seen within 1-2 weeks post-SRC for acute studies and 4 weeks post-SRC for studies focused on prolonged recoveries.

RESULTS

Twenty-two studies met the inclusion criteria (i.e., 8 regarding PA (PA-daily aerobic activity including light-moderate intensities), 8 evaluating active rehabilitation/exercise programs (20 minutes of daily aerobic exercise below symptom threshold), 6 examining a single bout of exertion). The methodological quality of the literature was assessed using the Downs and Black risk of bias (ROB) checklist. The ROB scores ranged from 7-24, with only two RCTs included. Studies demonstrated single bouts of exertion testing were safe and feasible. Daily PA or active rehabilitation/exercise programs led to a reduction in symptoms present and a decrease in number of days to medical clearance.

CONCLUSION

Following a brief period of rest (24-48 hours), individuals can gradually and safely return to PA below their physical symptom exacerbation thresholds. Further research is warranted to delineate how to optimize the timing, intensity, duration, and modality of PA impacts symptom resolution and physiological recovery following SRC.

Symptom and clinical recovery outcomes for pediatric concussion following early physical activity

OBJECTIVE

Recent research supports initiating physical activity as soon as 24 to 48 hours after concussion to reduce persistent postconcussive symptoms. However, this practice has not been widely adopted. The objective of this study was to evaluate the association of early physical activity with patient-reported and functional outcomes for pediatric patients following a concussion.

METHODS

A retrospective cohort of patients who presented to a pediatric sports medicine clinic (48% female, mean age14.3 ± 2.6 years, and mean 9.8 ± 5.7 days postconcussion) were evaluated. Patients were grouped based on whether they reported engaging in physical activity prior to presenting to the clinic. Patient- and parent-reported symptom frequency (Health and Behavior Inventory), 11 different clinical outcomes (including missed school, memory recall, and balance assessments), the presence of symptoms persisting beyond 28 days, and a subgroup analysis of those patients receiving exercise versus symptom-limiting activity prescriptions were examined. Outcomes were compared between physical activity groups using the Mann-Whitney U-test and the chi-square test. To adjust for the effect of potential confounders, a logistic binary regression model was constructed.

RESULTS

In total, 211 pediatric patients were included, 35 (17%) of whom reported early physical activity. A greater proportion of the no physical activity group reported a headache (85% vs 60%, p = 0.001). The no physical activity group also reported higher patient-reported (23.1 ± 13.4 vs 15.0 ± 13.4, p < 0.001) and parent-reported (19.4 ± 12.7 vs 11.2 ± 10.3, p = 0.001) symptom frequency at the initial visit. The early physical activity group had a lower proportion of patients with persistent symptoms (44% vs 22%, p = 0.02) and a shorter time to symptom resolution (15.6 ± 12.4 days vs 27.2 ± 24.2 days, p = 0.02). After adjusting for potential confounders, early physical activity was associated with 5.8 lower odds of experiencing persistent symptoms (adjusted OR 5.83, 95% CI 2.05-16.61; p = 0.001).

CONCLUSIONS

A significant association between early physical activity and decreased symptom burden was observed. A lower proportion of those patients who engaged in early physical activity experienced persistent symptoms 28 days postinjury. However, low rates of early physical activity prior to the initial clinic visit were also observed, indicating that this approach may not be well known by acute care or primary care providers, or is not widely adopted by patients and families.

More Physical Activity after Concussion Is Associated with Faster Return to Play among Adolescents

Concussion management has evolved to de-emphasize rest in favor of early introduction of post-injury physical activity. However, the optimal quantity, frequency and intensity of physical activity are unclear. Our objective was to examine the association between objective physical activity metrics and clinical recovery after concussion. We prospectively enrolled a cohort of 32 youth athletes with concussion, evaluated within 14 days of injury and after return-to-play (RTP) clearance. For two weeks after enrollment, we quantified steps/day and exercise frequency, duration, and intensity via wrist-worn actigraphy. We grouped participants by RTP clearance timing (<28 days vs. ≥28 days). Seventeen (53%) participants required ≥28 days post-concussion for RTP clearance. Groups were similar in age (14.9 ± 1.9 vs. 15.4 ± 1.5 years; p = 0.38), proportion of females (47% vs. 40%; p = 0.69), and concussion history (59% vs. 47%; p = 0.49). During the study period, the RTP ≥ 28 days group took fewer steps/day (8158 ± 651 vs. 11,147 ± 4013; p = 0.02), exercised fewer days/week (2.9 ± 2.4 vs. 5.0 ± 1.9 days/week; p = 0.01), and exercised fewer total minutes/week (117 ± 122 vs. 261 ± 219 min/week; p = 0.03). Furthermore, we observed ≥10,251 average steps/day, ≥4 exercise sessions/week, and exercising ≥134 total minutes/week were optimal cutpoints to distinguish between groups. These findings support the benefit of physical activity during concussion recovery.

The impact of exercise, sleep, and diet on neurocognitive recovery from mild traumatic brain injury in older adults: A narrative review

Mild traumatic brain injury (mTBI) accounts for a large majority of traumatic brain injuries sustained globally each year. Older adults, who are already susceptible to age-related declines to neurocognitive health, appear to be at an increased risk of both sustaining an mTBI and experiencing slower or impaired recovery. There is also growing evidence that mTBI is a potential risk factor for accelerated cognitive decline and neurodegeneration. Lifestyle-based interventions are gaining prominence as a cost-effective means of maintaining cognition and brain health with age. Consequently, inter-individual variations in exercise, sleep, and dietary patterns could influence the trajectory of post-mTBI neurocognitive recovery, particularly in older adults. This review synthesises the current animal and human literature centred on the mechanisms through which lifestyle-related habits and behaviours could influence acute and longer-term neurocognitive functioning following mTBI. Numerous neuroprotective processes which are impacted by lifestyle factors have been established in animal models of TBI. However, the literature is characterised by a lack of translation to human samples and limited appraisal of the interaction between ageing and brain injury. Further research is needed to better establish the therapeutic utility of applying lifestyle-based modifications to improve post-mTBI neurocognitive outcomes in older adults.

Influence of Aerobic Exercise Volume on Postconcussion Symptoms

BACKGROUND

Aerobic exercise has emerged as a useful treatment to improve outcomes among individuals who experience a concussion. However, compliance with exercise recommendations and the effect of exercise volume on symptom recovery require further investigation.

PURPOSE

To examine (1) if an 8-week aerobic exercise prescription, provided within 2 weeks of concussion, affects symptom severity or exercise volume; (2) whether prescription adherence, rather than randomized group assignment, reflects the actual effect of aerobic exercise in postconcussion recovery; and (3) the optimal volume of exercise associated with symptom resolution after 1 month of study.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Individuals randomized to an exercise intervention (n = 17; mean age, 17.2 ± 2.0 years; 41% female; initially tested a mean of 11.3 ± 2.8 days after injury) or standard of care (n = 20; mean age, 16.8 ± 2.2 years; 50% female; initially tested a mean of 10.7 ± 3.2 days after injury) completed an aerobic exercise test within 14 days of injury. They returned for assessments 1 month and 2 months after the initial visit. The aerobic exercise group was instructed to exercise 5 d/wk, 20 min/d (100 min/wk), at a target heart rate based on an exercise test at the initial visit. Participants reported their exercise volume each week over the 8-week study period and reported symptoms at each study visit (initial, 1 month, 2 months). Because of low compliance in both groups, there was no difference in the volume of exercise between the 2 groups.

RESULTS

There were no significant symptom severity differences between the intervention and standard-of-care groups at the initial (median Post-Concussion Symptom Inventory, 15 [interquartile range = 10, 42] vs 20 [11, 35.5]; P = .26), 1-month (4 [0, 28] vs 5.5 [0.5, 21.5]; P = .96), or 2-month (6.5 [0, 27.5] vs 0 [0, 4]; P = .11) study visits. Exercise volume was similar between groups (median, 115 [54, 225] vs 88 [28, 230] min/wk for exercise intervention vs standard of care; P = .52). Regardless of group, those who exercised <100 min/wk reported significantly higher symptom severity at the 1-month evaluation compared with those who exercised ≥100 min/wk (median, 1.5 [0, 7.5] vs 12 [4, 28]; P = .03). Exercising ≥160 min/wk successfully discriminated between those with and those without symptoms 1 month after study commencement (classification accuracy, 81%; sensitivity, 90%; specificity, 78%).

CONCLUSION

Greater exercise volume was associated with lower symptom burden after 1 month of study, and an exercise volume >160 min/wk in the first month of the study was the threshold associated with symptom resolution after the first month of the study. Because our observation on the association between exercise volume and symptom level is a retrospective and secondary outcome, it is possible that participants who were feeling better were more likely to exercise more, rather than the exercise itself driving the reduction in symptom severity.

Physical Activity Interventions for Individuals With a Mild Traumatic Brain Injury:: A Scoping Review

OBJECTIVE

To document the characteristics, measured outcomes, and effectiveness of physical activity (PA) interventions designed to improve health-related outcomes in individuals with a mild traumatic brain injury (mTBI) to assist in rehabilitation quality improvement efforts of a TBI rehabilitation program.

METHODS

A scoping review following a 6-step iterative framework search across 5 databases (MEDLINE, CINAHL, PsycINFO, SPORTDiscuss, and EMBASE) and the gray literature (Google) was performed. Selected PA interventions were designed for individuals of all ages and any mechanism of injury (eg, sports-related and falls). Data were charted, collated, and summarized according to the Consensus on Exercise Reporting Template checklist and domains of the International Classification of Functioning, Disability and Health. Involvement of clinical experts ensured tailoring of the knowledge synthesis to meet clinical needs.

RESULTS

Thirty-five articles and 14 gray literature records were retained. Five types of PA interventions were identified with the majority being multimodal. Reporting of PA intervention characteristics was highly variable across studies; many details necessary for intervention replication are missing. Study outcomes focused primarily on improving body functions and symptoms of mTBI, and less frequently on activities, participation, and health-related quality of life. The methodological quality of studies varies.

CONCLUSIONS

Identified PA intervention types offer various management options for healthcare providers. PA interventions may improve a wide range of health-related outcomes supporting the inclusion of PA in the management of individuals of all ages with mTBI. Higher-quality research and better reporting about intervention characteristics is however needed.

Cerebrovascular Neuroprotection after Acute Concussion in Adolescents

OBJECTIVE

To assess acute cerebrovascular function in concussed adolescents (14-21 years of age), whether it is related to resting cerebral hemodynamics, and whether it recovers chronically.

METHODS

Cerebral vasoreactivity and autoregulation, based on middle cerebral artery blood flow velocity, was assessed in 28 concussed participants (≤14 days of injury) and 29 matched controls. The participants in the concussion group returned for an 8-week follow-up assessment. Over the course of those 8-weeks, participants recorded aerobic exercise frequency and duration.

RESULTS

Between groups, demographic, clinical, and hemodynamic variables were not significantly different. Vasoreactivity was significantly higher in the concussed group (p = 0.02). Within the concussed group, 60% of the variability in resting cerebral blood flow velocity was explained by vasoreactivity and two components of autoregulation - falling slope and effectiveness of autoregulation (adjusted R²  = 0.60, p < 0.001). Moreover, lower mean arterial pressure, lower responses to increases in arterial pressure, and lower vasoreactivity were significantly associated with larger symptom burden (adjusted R²  = 0.72, p < 0.01). By the 8-week timepoint, symptom burden, but not vasoreactivity, improved in all but four concussed participants (p < 0.01). 8-week change in vasoreactivity was positively associated with aerobic exercise volume (adjusted R²  = 0.19, p = 0.02).

INTERPRETATION

Concussion resulted in changes in cerebrovascular regulatory mechanisms, which in turn explained the variability in resting cerebral blood flow velocity and acute symptom burden. Furthermore, these alterations persisted chronically despite symptom resolution, but was positively modified by aerobic exercise volume. These findings provide a mechanistic framework for further investigation into underlying cerebrovascular related symptomatology. ANN NEUROL 2021;90:43-51.

Aerobic Exercise for Sport-related Concussion: A Systematic Review and Meta-analysis

INTRODUCTION

Approximately 25% of people with sport-related concussion (SRC) experiences persistent symptoms. The 2016 Berlin consensus on SRC recommends symptom-limited aerobic exercise as a rehabilitation option for persistent symptoms after concussion. However, this recommendation is based on a limited body of knowledge because there is uncertainty about the effectiveness of such interventions. The objective of this systematic review is to assess the effects of symptom-limited aerobic exercise programs compared with control interventions on symptom intensity in individuals with SRC.

METHODS

A structured search was conducted in MEDLINE, EMBASE, CINHAL, and EBM reviews. Randomized clinical trials (RCT) including aerobic exercise programs as an intervention for SRC were included. After selection, the risk of bias and Grading of Recommendations, Assessment, Development and Evaluation recommendations were applied to pooled studies for quantitative analysis. Standard mean differences (SMD) and 95% confidence interval (CI) were calculated. A descriptive analysis was also performed.

RESULTS

Seven RCT (326 participants) in adolescent populations were included. Three of seven RCT had a high risk of bias. Symptom-limited aerobic exercise programs have a significant beneficial effect on the perception of symptoms (6 studies, 277 participants, low-quality evidence; pooled SMD, -0.44; 95% CI, -0.68 to -0.19). When introduced in the acute phase, symptom-limited aerobic exercise programs have a significant beneficial effect on symptomatic recovery compared with control interventions (3 studies, 206 participants, moderate quality evidence, pooled SMD, -0.43; 95% CI, -0.71 to -0.15).

CONCLUSIONS

Symptom-limited aerobic exercise programs are beneficial in improving symptoms of adolescents after an SRC. Good-quality studies are needed to determine effects on adults and on other outcomes.

Post-concussion symptoms in sports-related mild traumatic brain injury compared to non-sports-related mild traumatic brain injury

OBJECTIVES

To compare post-concussion symptoms in patients who sustained a sports-related mild traumatic brain injury (TBI) to those with non-sports-related mild TBI at 7 and 90 days post-injury.

METHODS

This prospective multicentre cohort study took place in seven Canadian Emergency Departments (ED). Non-hospitalized patients aged ≥ 14 years with a documented mild TBI that occurred ≤ 24 h of ED visit and a Glasgow Coma Scale score ≥ 13 were included. Main outcome measure was the presence of ≥ 3 symptoms on the Rivermead Post-concussion Questionnaire at 90 days post-injury. Secondary outcomes were the prevalence of (1) individual Rivermead Post-concussion Questionnaire symptom, (2) total Rivermead Post-concussion Questionnaire score ≥ 21 and (3) return to normal daily activities. Adjusted risk ratios (RR) were calculated.

RESULTS

1727 patients were included, 363 (21.0%) sustained a sports-related mild TBI. Similar proportions of patients with ≥ 3 symptoms, a Rivermead Post-concussion Questionnaire score ≥ 21 and those who returned to their normal daily activities were observed at 7 and 90 days post-injury. Sports-related mild TBI patients were at higher risk of poor concentration [RR: 1.3 (95% CI 1.05-1.54)] and non-return to sports activities [RR: 2.2 (95% CI 1.69-2.94)] at 7 days post-injury. At 90 days, sports-relate -mild TBI patients reported less fatigue [RR: 0.7 (95% CI 0.51-0.98)] and feeling of dizziness [RR: 0.6 (95% CI 0.35-0.99)].

CONCLUSION

Patients who sustained sports-related mild TBI could be at lower risk of experiencing symptoms such as fatigue and dizziness 90 days post-injury. Clinicians should be mindful that non-sports-related mild TBI patients may experience more post-concussion symptoms and that the level of physical activity may influence the patient's rehabilitation.

Pilot Study of Telehealth Delivered Rehabilitative Exercise for Youth With Concussion: The Mobile Subthreshold Exercise Program (MSTEP)

Background: Concussion is common, and up to 30% of youth develop persistent symptoms. Preliminary data suggests treatment with rehabilitative exercise is beneficial, but most programs require frequent in-person visits, which is challenging for youth in rural areas, and has been made more difficult for all youth during the COVID-19 pandemic. We have adapted an exercise intervention to be delivered via telehealth using Zoom and personal fitness devices, which could ensure access to this type of treatment. Objective: The goal of this study was to assess feasibility and acceptability of a telehealth delivered exercise intervention for concussion, the Mobile Subthreshold Exercise Program (MSTEP), and collect pilot data regarding efficacy. Materials and Methods: All youth received the 6-week MSTEP intervention which included wearing a Fitbit and setting exercise heartrate and duration goals weekly over Zoom with the research assistant. Youth completed standardized measures of concussive symptoms (Health Behavior Inventory, HBI), fear-avoidance (Fear of Pain Questionnaire, FOPQ) and health-related quality of life (Pediatric Quality of life Assessment, PedsQL), as well as a structured qualitative exit interview. We examined change in measures over time using mixed effects modeling, controlling for age, sex, prior concussion and duration of symptoms. We coded qualitative interviews using Thematic analysis. Results: We recruited 19 subjects, 79% female with average age 14.3 (SD 2.2) and mean duration of symptoms 75.6 days (SD 33.7). Participants wore the Fitbit on 80% of days, and completed 94% of surveys and 96% of Zoom calls. Concussive symptoms (HBI) decreased significantly over the 6 week intervention (-10.6, 95%CI: -16.0 to -5.1) as did fear-avoidance (-21.6, 95%CI: -29.8 to -13.5). PedsQL improved significantly during the same time period (+15.1, 95%CI: 8.6-21.6). Approximately three-quarters (76%) of youth rated their care as "excellent." Participants appreciated the structure of the guided exercise program and the support of the RA. They also enjoyed being able to track their progress with the Fitbit. Conclusion: This study provides evidence for the feasibility and acceptability of a telehealth delivered rehabilitative exercise intervention for youth with concussion. Further research utilizing a randomized controlled trial is needed to assess efficacy. Clinical Trial Registration: https://clinicaltrials.gov, identifier: NCT03691363. https://clinicaltrials.gov/ct2/show/NCT03691363.

The possible role of hydration in concussions and long-term symptoms of concussion for athletes. A review of the evidence

The purpose of this review is to address what is known, speculated, and hypothesized regarding the issue of hydration and concussions. Based on the question, “What impact does hydration have on the relative risk for suffering concussive injuries along with long-term ramifications that have been associated with concussive (and repeated subconcussive) traumas to the cerebral cortex?,” a search of available literature was performed through June 2019. Deducing from the available literature, we can stipulate that changes in hydration within the cerebral cortex increase the likelihood for disruption of neurofilament proteins, dysregulation of membrane dynamics of the neurons and exacerbate inflammation responses following head trauma. As such, it can be speculated that differences in incidence rates may be attributed to difference in tissue fluid based on athlete demographics, level of whole-body water balance, and degree of tissue dehydration more than selection of sport. Moreover, tissue hydration in combination with other inflammation factors provides the scaffolding for the development of long-term issues (e.g. chronic traumatic encephalopathy) associated with repetitive head trauma in athletes.

Early physical activity and clinical outcomes following pediatric sport-related concussion

OBJECTIVE

The objective of the study was to evaluate the clinical outcomes among patients who did and did not report engaging in early physical activity (PA) following sport-related concussion.

METHODS

We evaluated pediatric patients seen within 21 days of concussion. The independent variable was early PA engagement (since the injury and before initial clinical evaluation). Dependent variables included demographics, injury details, medical history, Health and Behavior Inventory (HBI) score, and balance, vestibular, and oculomotor function tests.

RESULTS

We examined data from 575 pediatric patients: Sixty-nine (12%) reported engaging in early PA (mean age=14.3±2.4 years; 30% female). The no PA group (mean age=14.5±2.4 years; 35% female) had significantly longer symptom resolution times than the early PA group (median= 16 [interquartile range (IQR)=8-24] vs. 10.5 [IQR=4-17] days; p=0.02). When controlling for pre-existing headache history and time from injury-evaluation time, the early PA group demonstrated lower odds of reporting current headache (adjusted odds ratio=0.14; 95% CI=0.07, 0.26), and reported lower symptom frequency ratings than the no PA group (b=-5.58, 95% CI=-8.94, -2.22).

CONCLUSIONS

Patients who did not engage in early PA had longer symptom duration, greater odds of post-injury headache, and greater symptoms at initial clinical evaluation. We cannot determine if patients engaged in early PA due to the lower symptom burden and higher functioning at the time of assessment, or if early PA positively affected outcomes. However, as early PA was associated with better post-injury outcomes, clinicians may consider supervised and structured early PA programs as a method to improve clinical outcomes following concussion.

RELEVANCE FOR PATIENTS

Children and adolescents who were engaged in PA after concussion presented to a clinic with less severe symptoms and had symptoms that resolved sooner compared to those who did not engage in early PA after concussion.

Exercise in the first week following concussion among collegiate athletes: Preliminary findings

OBJECTIVES

Our purpose was to examine the association between exercise after concussion with symptom severity, postural control, and time to symptom-resolution.

DESIGN

Longitudinal cohort.

METHODS

Collegiate athletes (n = 72; age = 20.2 ± 1.3 years; 46% female) with concussion completed a symptom questionnaire at initial (0.6 ± 0.8 days post-injury) and follow-up (2.9 ± 1.4 days post-injury) evaluations, and a postural control assessment at follow-up. Participants were grouped into those who exercised in between the time of injury and the follow-up evaluation and those who did not. Decisions regarding post-concussion exercise were made by a sports medicine team consisting of a single team physician and athletic trainers.

RESULTS

Thirteen athletes were not included in the current study, resulting in an 85% response rate. Thirteen of the athletes who completed the study exercised between evaluations (18%). There was no symptom resolution time difference between groups (median = 13 [IQR = 7-18] days vs. 13 [7-23] days; p = 0.83). Symptom ratings were similar between groups at the acute post-injury assessment (median PCSS = 18.5 [7.5-26] vs. 17 [14-40]; p = 0.21), but a main effect of group after adjusting for time from injury to assessment indicated the exercise group reported lower symptom severity than the no exercise group across both assessments (p = 0.044). The dual-task gait speed of the exercise group was higher than the no exercise group (0.90 ± 0.15 vs. 0.78 ± 0.16 m/s; p = 0.02).

CONCLUSIONS

Athletes who were recommended aerobic exercise after concussion did not have worse outcomes than those who were not. Exercise within the first week after concussion does not appear to be associated with detrimental clinical outcomes.

Pilot Randomized Controlled Trial of an Exercise Program Requiring Minimal In-person Visits for Youth With Persistent Sport-Related Concussion

Objective: To evaluate feasibility and acceptability of a sub-threshold exercise program with minimal in-person visits to treat youth with persistent sport-related concussion, and explore efficacy for improving concussive symptoms, health-related quality of life, and fear-avoidance. Study design: We conducted a pilot randomized controlled trial comparing a 6 week sub-threshold exercise program requiring only two in-person visits to active control (stretching) for 12-18 year old youth with persistent sport-related concussion. We measured moderate-to-vigorous physical activity pre- and post-intervention using accelerometry, and increased goals weekly via phone contact. We examined feasibility and acceptability using qualitative interviews. We used exponential regression to model differences in trajectory of concussive symptoms by experimental group, and linear regression to model differences in trajectory of health-related quality of life and fear-avoidance of pain by experimental group. Results: Thirty-two subjects randomized, 30 completed the study (n = 11 control, n = 19 intervention), 57% female. Youth and parents reported enjoying participating in the study and appreciated the structure and support, as well as the minimal in-person visits. Exponential regression modeling indicated that concussive symptoms declined more rapidly in intervention youth than control (p = 0.02). Health-related quality of life and fear-avoidance of pain improved over time, but were not significantly different by group. Conclusions: This study indicates feasibility and potential benefit of a 6 week subthreshold exercise program with minimal in-person visits for youth with persistent concussion. Potential factors that may play a role in improvement such as fear-avoidance deserve further study.