Does aerobic exercise affect memory, attention, working memory, and fatigue after acquired brain injury? A single-blinded, randomized controlled pilot study.

Only 12 patients concluded all parts, although 22 started, so the study was underpowered and the authors describe the results as preliminary. The study was planned for 16 patients in each group, but recruitment was limited by MRI access and hospital restrictions during the pandemic. No correction for multiple testing was applied because the sample was small and the study was exploratory. The control group received usual rehabilitation, not a passive control, so the contribution of aerobic exercise was tested against an active rehabilitation programme. Activities after aerobic exercise were not documented, so any effect of what followed the exercise session could not be assessed. Strict exclusions removed patients with moderate depression or anxiety, severe aphasia, and other medical or MRI contraindications, so the findings do not apply to all brain injury patients. Stroke and traumatic brain injury were mixed, and the authors note these groups may have different physiological responses to exercise. Four patients were excluded from the fMRI part because of a technical problem at the MRI unit. The study did not measure endurance or peak oxygen uptake as outcomes, so it cannot say whether aerobic fitness changed.

Do not conclude that aerobic exercise improves cognition because the group receiving aerobic exercise plus usual rehabilitation improved on PASAT (p = 0.042). The between-group comparisons were null, the study had only 12 analysed patients, and the contribution of aerobic exercise alone cannot be separated.