Verbal memory after epilepsy surgery in childhood

PURPOSE To investigate verbal memory after epilepsy surgery both group-wise and at the level of individual children, and to assess associations with side of surgery and removal of the temporal lobe. METHODS A prospective controlled study in a consecutive sample of 21 children undergoing epilepsy surgery, with comprehensive assessments of verbal memory before surgery and six, 12 and 24 months after surgery. For each patient, two age- and gender-matched controls were tested at similar intervals. Standardized regression-based (SRB) analysis was applied to compare post-surgical change in individual patients with change in controls. RESULTS Group-wise, average normed scores on verbal memory tests were higher after epilepsy surgery than before, corroborating earlier reports. By dint of empirically based SRB analysis, however, considerable individual differences in post-surgical change were revealed. Children with resections that included the left temporal lobe functioned significantly poorer than predicted on the basis of their pre-surgical performance. In contrast, verbal memory performance after surgery was consistent with pre-surgical baseline in the majority of children with resections that spared the left temporal lobe. CONCLUSIONS Despite cessation of epileptic seizures, verbal memory remains vulnerable in children who required surgery including the left temporal lobe. In most - but not all - children with other types of surgery, post-surgical verbal memory is consistent with their individual pre-surgical base level.