Magnetoencephalographic and electroencephalographic evaluation in patients with cryptogenetic partial epilepsy

Magnetoencephalography (MEG) has been applied for more than 20 years to the localization of the epileptic focus in partial epilepsies, but correlation with electroencephalographic (EEG) data in homogeneous groups of patients is scarce. Objective. - The aim of our work was to use EEG and MEG for the study of a group of adults and children affected by cryptogenetic partial epilepsy. Methods. - We analyzed the traces obtained from electroencephalographic and magnetoencephalographic recordings of 10 patients of ages ranging, from 7 to 38 years affected by cryptogenetic partial epilepsy. We evaluated the presence of commonly detected or uniquely detected spikes, and, whenever possible, we used MEG for localization of the epileptic focus. Results. - Three patients showed no epileptic activity during the EEG and MEG sessions. Overall agreement between EEG and MEG (presence of concordant spikes with the same localization shown by both techniques) was obtained in five patients. In one patient the spikes detected by EEG and MEG were different, and in another patient interictal activity was demonstrated exclusively by EEG. Conclusions. - EEG in this series was not inferior to MEG in terms of spike detection. Combination of EEG and MEG is feasible, better than each technique alone, and may be useful for non-invasive diagnosis and monitoring of pediatric and adult patients with partial epilepsies. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.