Reduced inhibition within primary motor cortex in patients with poststroke focal motor seizures

Abstract

To the Editor: We read with interest the article by Kessler et al.,1 who selected a subgroup of six patients with ischemic stroke in which the cortical silent period (CSP) after transcranial magnetic stimulation (TMS) was shortened by at least 25% in either the upper-or lower-affected limb compared with the unaffected side. Focal motor seizures occurred in five of these patients, whereas none of 76 control patients with normal or prolonged CSP developed poststroke seizures. As the CSP likely reflects GABAB-mediated inhibitory mechanisms within the primary motor cortex,2 the authors suggest that seizures following ischemic stroke may be due to a selective impairment of GABAergic interneurons at the epileptic focus. There are, however, some weaknesses in these findings. 1) From Table 2, it seems that significant intraindividual differences of CSP duration were found by using single trials as data samples. In …