title: Stereoelectroencephalography in presurgical assessment of MRI-negative epilepsy.
abstract: According to most existing literature, the absence of an MRI lesion is generally associated with poorer prognosis in resective epilepsy surgery. Delineation of the epileptogenic zone (EZ) by intracranial recording is usually required but is perceived to be more difficult in 'MRI negative' cases. Most previous studies have used subdural recording and there is relatively less published data on stereoelectroencephalography (SEEG). The objective of this study was to report the experience of our group in using SEEG in presurgical evaluation, comparing its effectiveness in normal and lesional MRI cases. One hundred consecutive patients undergoing SEEG for presurgical assessment were studied. Forty-three patients out of one hundred (43%) had normal MRI and 57 (57%) had lesional MRI. Successful localization was achieved with no difference between these two groups, in 41/43 (95%) normal MRI and in 55/57 (96%) lesional MRI cases (P = 1.00). Surgery was proposed in 84/100 patients and contraindicated in 16/100 with no significant difference between lesional and MRI-negative groups (P > 0.05). At 1 year follow-up, 11/20 (55%) of those having undergone cortectomy in the MRI-negative group and 21/40 (53%) in the lesional MRI group were entirely seizure free (P > 0.05) and these proportions were maintained at 2 years follow-up. Significant improvement in seizure control (ILAE outcome groups 1-4) was achieved in >90% cases with no difference between groups (P > 0.05). Of MRI-negative cases that underwent surgery, 10/23 (43%) had focal cortical dysplasia. This series showed that SEEG was equally effective in the presurgical evaluation of MRI-negative and lesional epilepsies.
authors.affiliation: INSERM, U 751, Laboratoire de Neurophysiologie et Neuropsychologie, Marseille, F-13000, France.
authors.forename: Aileen
authors.initials: A
authors.lastname: McGonigal
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.forename: Jean
authors.initials: J
authors.lastname: Régis
authors.forename: Maxime
authors.initials: M
authors.lastname: Guye
authors.forename: Martine
authors.initials: M
authors.lastname: Gavaret
authors.forename: Agnès
authors.initials: A
authors.lastname: Trébuchon-Da Fonseca
authors.forename: Henry
authors.initials: H
authors.lastname: Dufour
authors.forename: Dominique
authors.initials: D
authors.lastname: Figarella-Branger
authors.forename: Nadine
authors.initials: N
authors.lastname: Girard
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Péragut
authors.forename: Patrick
authors.initials: P
authors.lastname: Chauvel
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002648:Child; D004569:Electroencephalography / Q000009:adverse effects / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011300:Preoperative Care / Q000379:methods*; D013238:Stereotaxic Techniques; D016896:Treatment Outcome