Measurement of improvement on repeat exercise intolerance testing for suspected dysautonomia in protracted concussion recovery: a retrospective cohort study

Background: Research has demonstrated concussion likely causes autonomic dysfunction leading to exercise intolerance. Objective: To measure improvement in exercise intolerance due to suspected dysautonomia associated with protracted concussion recovery, using objective measurements on a Buffalo Concussion Treadmill Test (BCTT) following participation in a prescribed exercise program. Methods: This is a retrospective cohort study of 101 patient charts post-concussion. Exercise intolerance was assessed using a BCTT to identify suspected dysautonomia and an exercise prescription was provided using guidelines for treating concussion-associated exercise intolerance. Patients without symptom improvement and/or inability to achieve 80–85% of age-expected maximum heart rate (HR) without symptom exacerbation received a repeat BCTT. Results: Twelve patient charts met inclusion criteria and were included in data analysis. There were significant improvements from pre-intervention to post-intervention testing in: maximum BCTT stage mean scores (p = .02); maximum HR mean scores (p = .01); prescription HR (RxHR) mean scores (p = .01); and HR delta (HR (Formula presented.)) mean scores (p = .00). Conclusions: Maximum stage, HR threshold, RxHR, and newly identified HR delta (HR (Formula presented.)) are potential objective measurements of progress for dysautonomia treatment post-concussion. Future studies are indicated to create a tailored protocol in the management of protracted concussion-associated dysautonomia.