MEG, EEG AND MRI CORRELATION IN A [quot]PURE CULTURE[quot] OF TEMPORAL LOBE EPILEPTIC PATIENTS
Abstract number :
1.412
Submission category :
Year :
2003
Submission ID :
2248
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Tom[aacute]s Ortiz, Felipe Quesney, Rafael Garc[iacute]a de Sola, Alberto Fern[aacute]ndez, Fernando Maest[uacute], Carlos Amo Centro MEG, Universidad Complutense de Madrid, Madrid, Spain; Montreal Neurological Institute, McGill University, Montreal, QC,
We investigated the localizing effectiveness of MEG in a group of patients with temporal lobe epilepsy (TLE) who remained seizure free for at least a year after anterior temporal lobectomy ([ldquo]pure culture[rdquo]).
19 patients (7 females, mean age: 30 years) were submitted to anterior temporal lobectomy including amygdalectomy and partial hippocampectomy following extensive presurgical investigations which included: long-term video-EEG monitoring (34/64 channels) with extracranial and foramen ovale (13 patients) electrodes, 3D-MRI (1,5-3 Tesla), interictal SPECT, PET (18-FDG) and MEG (148 channels) without anticonvulsant withdrawal. MRI findings were: mesial temporal sclerosis (MTS)= 12 (one with dual pathology), neoplasm= 4, cortical gliosis= 1, diffuse temporal lobe gliosis= 1 and cavernoma= 1.
Patients were classified in two groups.
a) [underline]MTS group (12 patients):[/underline] MEG interictal epileptic discharges were recorded in 6/12 patients (50%). In 4 of these (33%) the epileptic activity was regional involving both mesial and neocortical temporal lobe structures. In 2 additional patients (16%) the epileptic anormality had a diffuse temporal neocortical distribution. Bilateral independent epileptiform discharges were seen in 3 of the former patients (25%). No isolated MEG epileptic activity was recorded from mesial temporal lobe structures.
b) [underline]Temporal neocortical group (7 patients):[/underline] Interictal epileptiform discharges were recorded in all 7 patients with neocortical MRI lesions. Its distribution was strictly neocortical without mesial temporal involvement and in 3 of them it was bilateral.
Our results show that MEG is a useful complementary technique in the presurgical evaluation of patients with TLE. Admittedly MEG has a higher yield in patients with temporal neocortical epilepsy as compared to patients with MTS. This probably represents a lower resolution of MEG in recording epileptiform potencials from mesial temporal structures, which are distant from the MEG sensors.