Abstracts

Epilepsy surgery in central regions is difficult because the risk of motor deficit. Epileptogenic network involving central regions with or without brain lesions may be accompanied by reorganization of the sensorimotor areas. The aim of this study was to explore this plasticity by noninvasive methods We explored 8 epileptic patients with focal motor seizures. We used 3 different electrophysiological methods to perform a cortical mapping of sensorimotor areas: the transcranial magnetic stimulation (TMS); the somatosensory evoked potentials (SEP); and the cortical event-related (de)synchronization (ERD/ERS) of central rhythms during a self-paced movement. Electroencephalogram (EEG) was recorded from 128 channels. SEP and ERD/ERS were computed from the deblurred EEG. Clinically, no patients displayed motor or sensory deficit out of epileptic seizures. Compared to the healthy cortical hemisphere, sensory and motor functions were shifted to cortical regions contiguous to epileptogenic region. In most of patients, results obtained with different electrophysiological methods showed a good concordance. We conclude that abnormal excitability of epileptogenic region induces a reorganization of motor and sensory functions within adjacent cortical regions. This plasticity can be investigated by noninvasive electrophysiological methods. It could allow treating these patients by surgery even in rolandic regions. (Supported by Fondation Fran[ccedil]aise de la Recherche sur l[apos]Epilepsie (FFRE))