β-Oscillations Reflect Recovery of the Paretic Upper Limb in Subacute Stroke.

Only 22 stroke survivors were enrolled, and only 15 were analysed at week 5 and 16 at week 12, so the sample was small and follow-up data were incomplete. The study was observational, so it shows associations between brain activity and motor scores, not that beta oscillations caused recovery. All stroke survivors received the same 2-week intensive physiotherapy, so the design cannot separate the effect of rehabilitation from natural recovery. The participants had mild to moderate subcortical middle cerebral artery strokes and were right-handed, so findings may not apply to more severe strokes, cortical strokes, or left-handed people. At week 12, ceiling effects of motor scores may have weakened correlations with baseline beta activity. The non-paretic hand showed early beta changes but no behavioural correlations, so the findings are specific to paretic movement. The main brain measure was magnetoencephalography, which required a magnetically shielded room and individual MRI co-registration.

Do not conclude that early beta activity can independently predict recovery. The week-3 lesion-side post-movement beta activity correlated with the 3-month arm score, but that correlation was no longer significant when the week-3 arm score was controlled for.