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.