Abstracts

Material specific memory deficits are often seen in temporal lobe epilepsy. Patients show verbal learning and confrontation naming deficits. These data were obtained lateralizing patients exclusively by MRI or interictal EEG (iEEG) data. Unilateral mesial temporal sclerosis (uMTS) is often a bilateral disease, with contralateral EEG abnormalities, which may impact on cognitive functioning. We compared neuropsychological scores (NP) in pure unilateral and bilateral uMTS patients. MRI-diagnosed uMTS, ages (17-55), education [gt]8 yrs, without other MRI lesions or significant psychiatric/neurologic disease. Patients underwent video-EEG monitoring (VEEG), iEEG, WADA test and a NP battery [digit span, vocabulary and object assembly subtests (WAIS III), Stroop I,II,III, Trail Making Test, Wisconsin Card Sorting Test, Rey Auditory Verbal Learning Test (RAVLT), Boston Naming Test (BNT), Verbal Fluency (FAS), Rey Figure (Immediate and Late Recall)]. Patients were divided in four groups: right and left, unilateral or bilateral (RU, LU, RB and LB) by a laterality index obtained from a summated score of iEEG, VEEG and WADA, compared to MRI findings. Normal controls were matched by age and education. Scores on individual neuriopsychological tests were compared among all groups and controls. 54 patients (30 or 56% men), 29 (or 54%) left MTS, education (10.6+/-2.1yrs.) and 18 controls (4 or 22% men) education (11.1+/-1.1yrs). 13 were RU, 20 LU, 12 RB and 9 LB.When comparing neuropsychological scores using MRI or iEEG isolatedly, classified as left or right, left MTS patients performed significantly worse in RAVLT (VI, VII and total score) and in FAS than controls and worse than controls and right MTS in BNT (p[lt]0.05, all tests) for both MRI or iEEG. When the 4 groups were compared, RU and LU differences disappeared. BL patients performed significantly worse than controls in RAVLT (VI, VII, total score), worse than controls, LU and RB in Stroop II and than RU in BNT. (p[lt]0.05, all tests). When iEEG was analyzed among the four groups, BL patients performed significantly worse than controls in RAVLT (VI, VII and total score) and worse than BR in BNT. Although it is widely accepted that left MTS patients show deficits in verbal learning and recall as well as confrontation naming, our data suggests that only patients with left MTS on MRI, but with bilateral involvement by other eletrophysiologic criteria (VEEG and iEEG) and cognitive functioning measures (WADA) perform significantly worse in episodic verbal memory and confrontation naming tasks. In this sample, pure left MTS patients do not show cognitive impairment in relation to right MTS patients (unilateral and bilateral) or controls. Bilateral temporal involvement with anatomic and/or functional involvement may be crucial for memory dysfunction in left temporal lobe epilepsy. (Supported by FAPESP.)