Motor cortex disinhibition in acute stroke

Objectives: To test whether a disinhibition occurs in the human motor corte x after stroke. Methods: Patients with a mild to moderate hemiparesis after an acute unilat eral ischemic stroke were compared with age-matched healthy controls. We us ed paired transcranial magnetic stimuli (TMS) to investigate intracortical inhibition and facilitation. Single TMS were applied to obtain a cortical s ilent period. Results: Intracortical inhibition was significantly reduced in the affected hemisphere at interstimulus intervals of 2, 3 and 4 ms. The cortical silen t period was significantly prolonged when compared to the unaffected hemisp here of the patients and to the control group. Motor cortex disinhibition o bserved in stroke patients was associated either with minimal impairment at the onset of symptoms or with rapidly improving motor functions. Conclusions: Motor cortex disinhibition occurs in humans after stroke. We s uggest that this disinhibition is indicative of compensatory mechanisms, wh ich are involved in recovery-related reorganization. (C) 2000 Elsevier Scie nce Ireland Ltd. All rights reserved.