Implementing a structured exercise program for persistent concussion symptoms: a pilot study on the effects on salivary brain-derived neurotrophic factor, cognition, static balance, and symptom scores

Non-invasive fluid biomarkers in the diagnosis of mild traumatic brain injury (mTBI): a systematic review

BACKGROUND

Despite approximately 55.9 million annual mild traumatic brain injuries (mTBIs) worldwide, the accurate diagnosis of mTBI continues to challenge clinicians due to symptom ambiguity, reliance on subjective report and presentation variability. Non-invasive fluid biomarkers of mTBI offer a biological measure to diagnose and monitor mTBI without the need for blood draws or neuroimaging. The objective of this study is to systematically review the utility of such biomarkers to diagnose mTBI and predict disease progression.

METHODS

A systematic review performed in PubMed, Scopus, Cochrane and Web of Science followed by a manual search of references without a specified timeframe. Search strings were generated and run (27 June 2022) by a research librarian. Studies were included if they: (1) included human mTBI subjects, (2) assessed utility of a non-invasive biomarker and (3) published in English. Exclusion criteria were (1) non-mTBI subjects, (2) mTBI not assessed separately from moderate/severe TBI, (3) required intracranial haemorrhage or (4) solely assesses genetic susceptibility to mTBI.

RESULTS

A total of 29 studies from 27 subject populations (1268 mTBI subjects) passed the inclusion and exclusion criteria. Twelve biomarkers were studied. Salivary RNAs, including microRNA, were assessed in 11 studies. Cortisol and melatonin were assessed in four and three studies, respectively. Eight salivary and two urinary biomarkers contained diagnostic or disease monitoring capability.

DISCUSSION

This systematic review identified several salivary and urinary biomarkers that demonstrate the potential to be used as a diagnostic, prognostic and monitoring tool for mTBI. Further research should examine miRNA-based models for diagnostic and predictive utility in patients with mTBI.

PROSPERO REGISTRATION NUMBER

CRD42022329293.

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.

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.

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.

The Role of Active Rehabilitation in Concussion Management: A Systematic Review and Meta-analysis

PURPOSE

This study aimed to conduct a systematic review and meta-analysis of active rehabilitation on concussion management. We also examined moderator variables that may contribute to differences across studies: symptom scale, physical activity type, time of injury to recruitment, and mechanism of injury.

METHODS

The standardized effect size of physical activity on concussion management was computed for 23 studies (29 effect sizes). Effect sizes were coded as positive when studies reported an improvement in symptom scores, which was represented by a decrease in postconcussive symptom scores.

RESULTS

The overall effect size of physical activity on concussion recovery was large and positive (g = 1.03). Subthreshold aerobic activity provided the largest effect size (g = 1.71), whereas multimodal interventions had a moderate effect size (g = 0.70). All other moderator variables produced positive effect sizes ranging from g = 0.59 to g = 1.46.

CONCLUSIONS

This systematic review and meta-analysis demonstrates that current evidence supports the notion that physical activity is beneficial in decreasing postconcussive symptoms in both the acute and chronic phases after concussion. The results indicate that unimodal subthreshold aerobic activity may be the best course of action compared with multimodal interventions. Despite this growing body of evidence, additional research is needed to determine the optimal intensity, duration, and time to initiation of aerobic exercise after concussion.

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.

Exercise for Sport-Related Concussion and Persistent Postconcussive Symptoms

CONTEXT

Emerging research supports the use of mild to moderate aerobic exercise for treating sport-related concussion (SRC) and persistent postconcussive symptoms (PPCS), yet the current standard of care remains to be strict rest. The purpose of this review is to summarize the existing literature on physical activity and prescribed exercise for SRC and PPCS.

EVIDENCE ACQUISITION

PubMed and Embase were searched in April of 2019 for studies assessing rest or prescribed exercise for SRC and PPCS. No specific search syntax was used.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

A majority of studies show that spontaneous physical activity is safe after SRC and that subsymptom threshold aerobic exercise safely speeds up recovery after SRC and reduces symptoms in those with PPCS. Exercise tolerance can safely be assessed using graded exertion test protocols within days of injury, and the degree of early exercise tolerance has diagnostic and prognostic value.

CONCLUSION

Subsymptom threshold aerobic exercise is safe and effective for the treatment of SRC as well as in athletes with PPCS. Further research is warranted to establish the most effective method and dose of aerobic exercise for the active treatment of SRC and whether early exercise treatment can prevent PPCS in athletes.

STRENGTH OF RECOMMENDATION TAXONOMY

2.