[Relation between inter-critical and critical stereoelectroencephalographic elements: consequences on the results of...

Surgical results in 31 cases of cortectomy for epilepsy are reported with stereoelectroencephalographic recordings. The relationships between the cortical area characterized by inter-ictal spikes (irritative area) and the site of the ictal discharge (epileptogenic focus) lead to define two situations: the two areas were considered similar in 11/21 temporal lobe epilepsy and 3/10 frontal lobe epilepsy. Surgical results were then excellent; when the irritative area was not totally included in the cortectomy, surgical results were less good. This situation was more frequent in frontal lobe (70 p. 100) than in temporal lobe epilepsy (47.5 p. 100). However in 7/17 of theses cases, the seizures disappeared or decreased by 90 p. 100. Therefore the irritative area can be considered hetereogeneous. Ictal and interictal stereo-EEG data contain non-redundant information. The inter-ictal EEG patterns contributing to the definition of the epileptogenic area are discussed.