Abstracts

Rationale: To assess verbal memory outcomes following surgery for treatment of temporal lobe epilepsy (TLE) in a pediatric sample. We hypothesized that TLE surgery would be associated with postsurgical decline in verbal memory, with left sided surgery greater than right.Methods: Thirty-nine patients (25 left, LTLE; 14 right, RTLE) were identified through archival record review. Mean age at surgery was 15.5 years (SD=3.6; range=8-21). Wada/fMRI testing documented left-lateralized language in 28 patients (1 right lateralized, 7 bilateral activation, 3 unknown). All patients had been seizure free for six months at the time of the post-surgical assessment (Engel Class I). As part of standard of care, participants completed neuropsychological testing prior to surgery and within the first year after surgery (LTLE, mean=8.09 months, SD=2.5; RTLE, mean=11.14 months, SD=8.93 [NS]). The battery included a list learning (California Verbal Learning Test-Children’s and Adult Versions [CVLT]) and story memory (Children’s Memory Scale [CMS] or Wechsler Memory Scale [WMS]) test. Repeated measures analyses of variance were performed, with Time (pre/post surgery) the within-subjects factor and Hemisphere (surgery side) the between-subjects factor. Paired sample t-tests were conducted for exploratory post-hoc analysis. Reliable change indices (RCI) corrected for practice effects were also calculated (90%CI).Results: There were significant main effects of Time for CVLT Learning and Delayed Recall (p< .05), with scores lower after surgery. However, the Time X Hemisphere interaction did not reach statistical significance. For story memory, outcomes were analyzed separately by age (<16 years, N =19; ≥ 16 years, N = 20) because of differences in measures, reducing the power to detect differences. Although there were no statistically significant effects, scores were lower after left TLE surgery for the immediate story memory condition (younger group only, p< .05). The RCI analyses documented a decline in 13 (9 left) patients on CVLT Learning and 13 (9 left) on CVLT Delayed Recall (RCI 90%CI). Story memory decline was observed in 14 (12 left) and 15 (12 left) patients for the Immediate and Delayed conditions, respectively.Conclusions: Verbal memory declines are prevalent in pediatric patients after dominant, left temporal lobe surgery, with implications for pre-surgical decision-making.