Biomagnetic profiles of verbal memory success in patients with mesial temporal lobe epilepsy

• Published in: Epilepsy & behavior Vol. 16; no. 3; pp. 527 - 533
• Main Authors: Maestú, F, Campo, P, García-Morales, I, del Barrio, A, Paul, N, del Pozo, F, Ortiz, T, Gil-Nagel, A
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2009
• Subjects: Adult; Analysis of Variance; Brain Mapping; Case-Control Studies; Cerebral Cortex - physiopathology; Epilepsy; Epilepsy, Temporal Lobe - complications; Epilepsy, Temporal Lobe - pathology; Epilepsy, Temporal Lobe - surgery; Female; Functional imaging; Functional Laterality; Hippocampus - pathology; Humans; Magnetoencephalography; Male; Memory Disorders - diagnosis; Memory Disorders - etiology; Mesial temporal lobe; Neurology; Neuropsychological Tests; Reaction Time - physiology; Reorganization; Sclerosis - pathology; Subsequent memory; Verbal Learning - physiology; Magnetoencephalography; Mesial temporal lobe; Epilepsy; Subsequent memory; Reorganization; Functional imaging
• ISSN: 1525-5050; 1525-5069
• DOI: 10.1016/j.yebeh.2009.09.007

Abstract The risk of cognitive decline after mesial temporal lobe (MTL) resection in the dominant hemisphere for treatment of epilepsy has been assessed with the intracarotid amytal procedure and functional neuroimaging. In this study we used magnetoencephalography (MEG) to analyze memory profiles in patients with left hippocampal sclerosis (HS). Biomagnetic brain activity related to successful memory was compared in nine patients with left HS and nine age-matched controls. Patients manifested a higher number of activity sources over the right inferior parietal lobe in the late portion of the time window, and higher activity in the right than in the left MTL between 400 and 800 ms. This was reinforced by a −0.46 MTL laterality index, which indicates right MTL dominance. Controls showed a higher number of dipoles in the left anterior ventral prefrontal region, between 400 and 600 ms, and in the left MTL across the whole time window. Three patients who underwent a left temporal lobectomy, were seizure free, and who did not exhibit memory impairment after left temporal lobectomy, showed no activity in the left MTL presurgically. These results could support the ability of MEG to describe the time-modulated brain activity related to memory success in patients with epilepsy with left HS.