EEG and neuroimaging studies in young children having epilepsy surgery

The aim of this study was to evaluate the yield of electroencephalography and structural and functional neuroimaging in children having resective epilepsy surgery before 5 years of age. Charts of all 28 children (54% male) having resective surgery before 60 months of age at the Mayo Clinic between January 2002 and June 2009 were reviewed. Mean age at seizure onset was 9.6 months (S.D. 12.7); mean age at surgery was 28.8 months (S.D. 17.7). Sixteen children (57%) had partial-onset seizures, 8 (29%) had partial-onset seizures and spasms, and 4 (14%) had spasms alone. Initial surgery type was hemispherectomy in 6 cases, multilobar resection in 8, temporal in 7, and extratemporal in 7. Only 10 of the 25 children (40%) with recorded seizures preoperatively had a well-localized, single ictal focus. Ictal discharge was generalized in 8/25 cases (32%), both generalized and focal in 1 case (4%), hemispheric in 4 cases (16%), and absent in 1 case (4%). Findings from magnetic resonance imaging were abnormal in 27 cases, and revealed focal pathology in 20. Surgical outcome was favorable, with 18 of the 27 survivors (67%) being free, or nearly free, of disabling seizures. In summary, electroencephalography frequently failed to indicate a single ictal focus in young children having epilepsy surgery. In contrast, magnetic resonance imaging was more helpful, revealing focal abnormalities in 74% of patients.