Abstracts

RATIONALE: The assertion of benignity of Benign Epilepsy with Centro-Temporal Spikes (BECTS) has been challenged by case and group studies showing scholastic or cognitive disorders. Those data however do not allow to tell if the deficits are due to a basic brain dysfunction, or to the effect of the ungoing epileptic activity on developing cognitive functions. In a previous study, our group evidenced subtle neuropsychological impairments associated with BECTS. The aim of this study is to further analyse the relationship of these impairments with EEG abnormalities. METHODS: We collected the assessments of 18 children issued from a clinical, neuropsychological and neurophysiological prospective follow-up. The data concerned each semestrial evaluation from the first seizure, to 18 months. We focused on several WISCR verbal on non verbal subtests more sensitive to epilepsy as shown in our previous study: VIQ, Problems, Digits, PIQ, Koh's cube, Coding test. The neurophysiological measurments consisted in quantification of wake and sleep EEG (Number of spike and waves during 40 mn)localization of abnormalities, spike and waves and/or slow focus. Non parametric statistical methods applied to the data at the beginning and the 18 month of follow up. RESULTS: The first main result concerned the absence of specific effect of focus lateralization on IQ and specific subtets studied. The second result evidenced relationship between the presence of slow focus and the performances on Koh's cube subtest and PIQ wich was significant only after 18 months of evolution. The third result also showed that low peformances on Koh's cube and coding test were correlated with the amount of spike and waves on sleep EEG recorded between 12 and 18 months of evolution. CONCLUSIONS: These results show clear relationship between the localization of slow wave focus and cognitive perforamces. The most predictive neurophysiological abnormality is the persistence of a slow focus. The slow EEG focus appears to be significantly correlated to neuropsychological impairment wich seems to be acquired during the active phase of the epilepsy.