Aerobic exercise and cognitive function in chronic severe traumatic brain injury survivors: a within-subject A-B-A intervention study

Background Following acute and sub-acute rehabilitation from severe traumatic brain injury (TBI), minimal to no efficacious interventions to treat ongoing cognitive deficits are available. Aerobic exercise is a non-invasive behavioral intervention with promise to treat cognitive deficits in TBI populations. Methods Six individuals, aged 24-62 years, with chronic (> 8 months since injury) severe (Glasgow Coma Scale of 3-8) TBI were recruited from two outpatient rehabilitation centers. In an A-B-A study design, 20-weeks of supervised aerobic exercise interventions were delivered three times per week (phase B) in addition to participants typical rehabilitation schedules (phases A). The effect of phase B was tested on a trail making test part B (primary outcome measure of executive function) as well as objective daily physical activity (PA), using both group level (linear mixed effect models) and single subject statistics. Results Five of six participants increased trail-making test part B by more than 10% pre-to-post phase B, with three of six making a clinically meaningful improvement (+ 1SD in normative scores). A significant main effect of time was seen with significant improvement in trail-making test part B pre-to-post exercise (phase B). No significant effects in other planned comparisons were found. Statistically significant increases in daily moderate-to-vigorous PA were also seen during phase B compared to phase A with three of six individuals making a significant behaviour change. Conclusions The addition of supervised aerobic exercise to typical rehabilitation strategies in chronic survivors of severe TBI can improve executive set shifting abilities and increase voluntary daily PA levels. Trial registration Retrospective trial registration on July 11 2024 with trial number: ISRCTN17487462.