Motor cortex disinhibition of the unaffected hemisphere after acute stroke.

We studied motor cortex excitability in the nonlesioned hemisphere of patients with a large cortical infarction. Patients with a severe hemiparesis due to a stroke were compared with age-matched, healthy controls. Paired transcranial magnetic stimuli were applied over the unaffected hemisphere to investigate intracortical inhibition and facilitation. In the patient group, intracortical inhibition was reduced. We suggest that this disinhibition is due to an impairment of transcallosal fibers and may affect recovery. Copyright 2000 John Wiley & Sons, Inc.