Autonomic system -- concussion and sport

CONTEXT: Early physical activity (PA) after concussion may promote symptom resolution. Prior studies have investigated exercise frequency/duration, yet precise PA intensity or volume required for optimal recovery requires further investigation. moderate to vigorous physical activity (MVPA) is beneficial for physical health. We investigated whether sedentary time, light activity time, MVPA time, or activity frequency in the weeks following concussion are associated with time to symptom resolution among adolescents...

OBJECTIVE: This systematic review aims to investigate the adaptations of the autonomic nervous system (ANS) after a concussion by measuring HRV in athletes over the age of 16 after injury. METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Web of Science, Pubmed, SCOPUS, and Sport Discus were searched using predefined search terms to identify relevant original cross-sectional, longitudinal, and cohort epidemiological studies published before December 2021...

BACKGROUND: Growing evidence indicates early exercise may improve symptoms and reduce clinical recovery time after concussion, but research examining collegiate student-athletes is scarce. OBJECTIVE: The aim of this study was to compare symptom recovery time, clinical recovery time, and persisting post-concussion symptom (i.e., symptoms ≥ 28 days) prevalence by the timing of light exercise initiation before the graded return to play (RTP) protocol among concussed participants...

BACKGROUND: Persistent post-concussion symptoms (PPCS) affect between 34 and 46% after a mild traumatic brain injury (mTBI). Many also experience exercise intolerance. Sub-symptom threshold aerobic exercise, SSTAE (exercise at an intensity level that does not increase symptoms) is proposed as a treatment to both reduce the symptom burden and increase the exercise tolerance after the injury. It is unclear if this also applies in a more chronic phase after mTBI. MAIN PURPOSE: The main purpose of this study is to evaluate whether SSTAE in addition to ordinary rehabilitation will lead to clinically meaningful improvement of symptom burden, normalize exercise tolerance, increase physical activity, improve health-related quality of life, and reduce patient-specific activity limitations compared to a control group that only receives ordinary rehabilitation...

OBJECTIVE: Autonomic nervous system dysregulation is a common consequence of traumatic brain injury (TBI). Heart rate variability (HRV) is a cost-effective measure of autonomic nervous system functioning, with studies suggesting decreased HRV following moderate-to-severe TBI. HRV biofeedback treatment may improve post-TBI autonomic nervous system functioning and post-injury emotional and cognitive functioning. We provide a systematic evidence-based review of the state of the literature and effectiveness of HRV biofeedback following TBI...

OBJECTIVE: To assess the performance on the Buffalo Concussion Treadmill and Bike Tests in nonathletic people following a mild-to-moderate traumatic brain injury. SETTING: An outpatient rehabilitation clinic. PARTICIPANTS: Forty-nine patients with mild-to-moderate traumatic brain injury who underwent the Buffalo Concussion Treadmill or Bike Test as usual clinical care. DESIGN: A retrospective clinical audit. MAIN MEASURES: Demographics and brain injury-specific clinical data, Depression Anxiety Stress Scale; Rivermead Post-Concussion Symptom Questionnaire, and performance outcomes on the Buffalo Concussion Treadmill or Bike Test...

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...

There is no single gold standard test to diagnose sport-related concussion (SRC). Concussion-related exercise intolerance, i.e., inability to exercise to the individual's appropriate level due to exacerbation of concussion-like symptoms, is a frequent finding in athletes early after SRC that has not been systematically evaluated as a diagnostic test of SRC. We performed a systematic review and proportional meta-analysis of studies that evaluated graded exertion testing in athletes after SRC. We also included studies of exertion testing in healthy athletic participants without SRC to assess specificity...

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...

CONTEXT: The Buffalo Concussion Treadmill Test (BCTT) is a standard assessment of exercise tolerance utilized for exercise prescription following concussion and to inform decisions regarding return to play. One limitation of the BCTT is that interpretation of test results is dependent on individuals' self-report of symptom exacerbation with exertion. Symptoms following concussion are significantly underreported or unreported. Combining objective neurocognitive assessment with exercise tolerance testing may enable clinicians to objectively identify those requiring further assessment or rehabilitation before return to play...

OBJECTIVE: The objective of this study was to identify the main determinants of heart rate variability (HRV) in male athletes aged 14 to 21 years who practice competitive contact sports and to integrate these determinants with the aim of defining normative values of short-term HRV in the time and frequency domains. METHODS: Participants ( n  = 369) were aged 14 to 21 years and included 221 football players and 148 ice hockey players. HRV was measured for 5 min at rest, and standard HRV parameters in the time and frequency domains were calculated...

OBJECTIVE: This prospective study investigated and analyzed the clinical characteristics and prognosis of paroxysmal sympathetic hyperactivity (PSH) in patients with severe nontraumatic brain injury. METHODS: Patients presenting with severe nontraumatic brain injury with PSH from July 2018 to June 2019 were enrolled. A PSH assessment measure ≥ 8 points was used as the criterion for PSH. Clinical data, indicators related to PSH, treatment effects and the prognosis were prospectively collected and analyzed...

OBJECTIVE: To examine the effect of a readily accessible, structured aerobic exercise intervention on days to asymptomatic status and days to medical clearance compared to usual care exercise prescription in a cohort of adolescents and young adults following sport-related concussion (SRC). METHODS: A longitudinal, randomized, non-blinded clinical trial consisting of a structured aerobic exercise protocol (SAEP) group and a usual care exercise prescription (UCEP) group...

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 hours of rest immediately following concussion with the gradual introduction of light-to-moderate intensity aerobic exercise thereafter...

(1) Background: Cerebral autoregulation is altered during acute mild traumatic brain injury, or concussion. However, it is unknown how a history of concussion can impact cerebral haemodynamic activity during a task that elicits an autoregulatory response. (2) Methods: We assessed cerebral haemodynamic activity in those with a history of three or more concussions. The study included 44 retired athletes with concussion history and 25 control participants. We recorded participants' relative changes in right and left pre-frontal cortex oxygenation collected by near-infrared spectroscopy and continuous beat-to-beat blood pressure measured by finger photoplethysmography...

CONTEXT: After a sport-related concussion, many athletes experience persisting neurophysiological alterations. These alterations may be absent at rest but emerge during moments of physiological stress. Unnoticed and untreated neurophysiological dysfunction may negatively affect long-term neurologic health in adolescent athletes, as they are at a critical point in development. OBJECTIVE: To assess cardio-autonomic functioning in athletes with and those without a history of concussion by quantifying measures of heart rate variability (HRV) during times of physical and mental exertion...

OBJECTIVE: The aims of this systematic review and meta-analyses were to evaluate the effects of exercise on the functional capacity and quality of life (QoL) of people with acquired brain injury (ABI) and to analyze the influence of training variables. METHODS: Five electronic databases (MEDLINE, Cochrane Library, CINAHL, SportDiscus, and Web of Science) were searched until October 2021 for clinical trials or experimental studies examining the effects of exercise on the functional capacity and QoL in adults with ABI and comparing exercise interventions to nonexercise (usual care)...

The purpose of this retrospective chart review was to compare sports-related concussion (SRC) recovery time in protracted recovery (≥28 days) patients who were prescribed physical therapy (PPT) with those who were only provided a home exercise program (HEP). We hypothesized PPT would be associated with shorter recovery times relative to HEP. Associations were evaluated with multivariable zero-truncated negative binomial regressions. Among the 48 (30.2%) PPT and 111 (69.8%) HEP patients, the majority were female (57...

Current methods to diagnose concussions are subjective and difficult to confirm. A variety of physiological biomarkers have been reported, but with conflicting results. This study assessed heart rate variability (HRV), spontaneous baroreflex sensitivity (BRS), and systolic blood pressure variability (BPV) in concussed athletes. The assessment consisted of a 5-min seated rest followed by a 5-min (0.1 Hz) controlled breathing protocol. Thirty participants completed baseline assessments. The protocol was repeated during the post-injury acute phase (days one to five)...

Concussion induces the rapid onset of a short-lived neurophysiological disturbance that often results in autonomic nervous system dysfunction. This dysfunction affects both cardiovascular functioning and higher cognitive processing, inducing post-concussion clinical symptoms (somatic, cognitive, and/or emotional) and functional disturbances (impaired balance, cognition, and visual-vestibular performance). Current concussion rehabilitation paradigms using aerobic exercise may improve concussion symptoms. Additionally, cognitive training-focused rehabilitation interventions may improve cognitive function post-injury...