Effect of Graded Aerobic Exercise in Mild Traumatic Brain Injury

Background: TBI is a public health challenge of considerable, but insufficiently recognized proportions. Therefore, a concerted effort should be made to reduce the burden and impact of TBI. Health care providers are in need of standardization of the medical examination and targeted individual interventions with potential to treat PCS. Main purpose: The main purpose of this study is to evaluate whether a progressive, sub-symptom threshold aerobic exercise program in addition to ordinary rehabilitation will lead to clinically meaningful reduction in symptom burden, normalize exercise tolerance and improve health-related quality of life compared to a control group that only receives ordinary rehabilitation. In addition, changes in ANS function will be assessed in both the intervention and the control group. Design: Randomized, controlled, single-blind parallel-group study with two measurement points; T0 at baseline and T1 after the intervention. Method: The Buffalo Concussion Treadmill Test (BCTT) will be used to expose exercise intolerance, and participants with exercise intolerance will be randomized to the intervention group or the control group. Both groups will receive ordinary rehabilitation. The intervention group will in addition receive an individualized (based on BCTT) sub-symptom threshold aerobic exercise program for 12 weeks. To assess ANS function, Arterial spin labeling (ASL) MRI and Cold Pressor Test (CPT) will be performed at T0 and T1. Symptom burden will be assessed by Rivermead Post-concussion Symptom Questionnaire (RPQ) and other patient reported outcomes measurements including self-reported autonomic symptoms (the Composite Autonomic Symptom Score 31) will also be used. Clinical relevance: Self-reported ANS, exercise intolerance testing, the CPT and ASL-MRI could prove to be useful clinical assessment tools to confirm the PCS-diagnosis and to determine readiness to return to preinjury level of day-to-day activities.