Early targeted heart rate exercise is safe and May hasten return-to-duty in service members with acute concussion, a preliminary study.

OBJECTIVE: To evaluate the feasibility of an exercise tolerance assessment and intervention added to the Progressive Return to Activity Clinical Recommendations (PRA-CR) in acutely concussed service members (SMs). METHODS: This non-randomized, pilot trial was performed at one center. SMs in the experimental group (ERG) performed the Buffalo Concussion March-in-place Test (BCMT) at every clinic visit and were prescribed at least 20 minutes/day of targeted exercise in addition to PRA-CR. Data for the control group (SCG) were extracted from the same clinic immediately prior to ERG. SMs in both groups were assessed by the same clinician to determine return-to-duty. RESULTS: BCMT identified concussion-related exercise intolerance in 100% (n = 14) at screening visit (mean 3.4 days after injury) and in 0% (n = 7) who had recovered. No adverse effects were associated with BCMT. The estimated recovery time for ERG who performed the exercise intervention (n = 12) was 17.0 (12.8, 21.2) days and for SCG (n = 15) was 23.7 (19.9, 27.5) days (p = 0.039). CONCLUSION: Assessment of exercise tolerance was feasible and could be incorporated into the PRA-CR. Future definitive, randomized controlled trials should be performed to assess the effectiveness of exercise reset program for SMs after concussion.

Association of Concussion History and Prolonged Recovery in Youth.

OBJECTIVE: To determine the number of prior concussions associated with increased incidence of persistent postconcussive symptoms (PPCS) in a cohort of acutely concussed pediatric patients. DESIGN: Prospective observational cohort study. SETTING: Three university-affiliated concussion clinics. PARTICIPANTS: Two hundred seventy participants (14.9 ± 1.9 years, 62% male, 54% with prior concussion) were assessed within 14 days of concussion and followed to clinical recovery. Participants with a second head injury before clinical recovery were excluded. MEASURES AND MAIN OUTCOME: Concussion history, current injury characteristics, recovery time, and risk for prolonged recovery from current concussion. RESULTS: There was no statistically significant change in PPCS risk for participants with 0, 1 or 2 prior concussions; however, participants with 3 or more prior concussions had a significantly greater risk of PPCS. Twelve participants sustained a subsequent concussion after clinical recovery from their first injury and were treated as a separate cohort. Our secondary analysis found that these participants took longer to recover and had a greater incidence of PPCS during recovery from their latest concussion. CONCLUSION: Pediatric patients with a history of 3 or more concussions are at greater risk of PPCS than those with fewer than 3 prior concussions.

Sex differences in the Buffalo Concussion Treadmill Test in adolescents with acute sport-related concussion.

OBJECTIVES: The Buffalo Concussion Treadmill Test (BCTT) is a safe and validated tool to assess exercise tolerance after sport-related concussion (SRC). Sex differences may affect the interpretation of this systematic exertion test in the concussed population, which is important for clinicians. The purpose of this study was to examine sex differences in BCTT performance in adolescents with acute SRC. DESIGN: Prospective cohort. METHODS: Male (n = 103, 15.3 ±â€¯2 years) and female (n = 87, 15.1 ±â€¯2 years) adolescents with SRC performed the BCTT within 10 days of injury. Heart rate (HR), HR threshold (HRt), Delta HR (difference between resting HR and HRt), symptom severity on Visual Analog Scale (VAS) and symptoms exacerbated on the BCTT were collected and compared. RESULTS: Males had lower resting HR (M: 70.9 ±â€¯12 vs F: 75.7 ±â€¯13 bpm, p < 0.01) and reached a lower HRt than females (M: 134.7 ±â€¯23 vs F: 141.5 ±â€¯25 bpm, p = 0.05). Sexes did not differ on Delta HR (M: 63.8 ±â€¯26 vs F: 65.9 ±â€¯24 bpm, p = 0.57), total treadmill time (M: 9.3 ±â€¯5 vs F: 8.4 ±â€¯4 min, p = 0.20), maximum VAS (M: 5.0 ±â€¯2 vs F: 5.4 ±â€¯2, p = 0.18) or incidence of a change in VAS (M: 91% vs F: 94%, p = 0.43) on the BCTT. CONCLUSIONS: Although males may reach symptom exacerbation at a slightly lower mean HRt than females on the BCTT within 10 days of SRC, the BCTT provides comparable information and both sexes reach symptom exacerbation at similar Delta HR.

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.

Blunted Cardiac Parasympathetic Activation in Student Athletes With a Remote History of Concussion: A Pilot Study.

Introduction: Blunted cardiac autonomic nervous system (ANS) responses, quantified using heart rate variability (HRV), have been reported after sport-related concussion (SRC). Research suggests this persists beyond clinical recovery. This study compared cardiac parasympathetic responses in student athletes with a remote history of SRC (> 1-year ago, Concussion History: CH) with those who reported no lifetime history of SRC (Concussion Naïve: CN). Design: Retrospective nested case-control. Setting: University laboratory. Patients or Other Participants: CH (n = 9, 18.3 ± 2 years, 44% male, median 2 years since injury) were student athletes with a remote history of concussion(s) from more than 1 year ago. CN (n = 21, 16.7 ± 3 years, 67% male) were student athletes with no lifetime history of concussion. Exclusion criteria included taking medications that could affect ANS function, history of concussion within the past year, persistent concussion symptoms, lifetime history of moderate to severe brain injury, and lifetime history of more than 3 concussions. Material and Methods: Participants performed the Face Cooling (FC) test for 3-min after 10-min of supine rest while wearing a 3-lead electrocardiogram in a controlled environment. Outcome Measures: Heart rate (HR), R-R interval (RRI), root mean square of the successive differences (RMSSD) of RRI, high frequency (HF) and low frequency to HF (LF:HF) ratios. Results: At baseline, CH had a lower resting HR than CN (62.3 ± 11 bpm vs. 72.9 ± 12, p = 0.034). CH had a different HR response to FC than CN (+8.9% change from baseline in CH vs. -7.5% in CN, p = 0.010). CH also had a smaller RMSSD increase to FC than CN (+31.8% change from baseline in CH vs. +121.8% in CN, p = 0.048). There were no significant group differences over time in RRI (p = 0.106), HF (p = 0.550) or LF:HF ratio (p = 0.053). Conclusion: Asymptomatic student athletes with a remote history of concussion had a blunted cardiac parasympathetic response to FC when compared with athletes with no lifetime history of concussion. These data suggest that an impaired autonomic response to a physiological stressor persists after clinical recovery from SRC for longer than previously reported.