Abstracts

Rationale: Nonlesional extratemporal seizures present some of the most difficult treatment decisions. Seizure control is more variable, and the consequences of resection can be more severe (Cohen-Gadol, 2006). Outcome data on this population has been limited, especially for children. Studies completed by Sinclair et al. (2004) and Bauman et al. (2005) included extratemporal resections, but only 4 and 5 nonlesional cases were reported, respectively. Paolicchi et al. (2000) investigated 19 cases who had nonlesional extratemporal epilepsy, but cognitive outcomes were not included. Sinclair et al. used cognitive data, but their study did not report cognitive outcomes specifically for the nonlesional cases. The present investigation attempts to expand our understanding of cognitive outcomes in children who undergo nonlesional extratemporal lobe epilepsy surgery. Methods: We completed an archival investigation of 25 children with nonlesional extratemporal lobe epilepsy who underwent surgery and neuropsychological assessment at St. Louis Children’s Hospital from 1994 to 2006 (13 frontal; 2 parietal; 2 occipital; 8 multiple). Mean age at the time of surgery was 12 years (12 male, 13 female). Neuropsychological assessments were completed before and after surgery (mean follow-up of 13 months). A repeated measures ANOVA was completed with each variable, and two-factor analyses of variance were completed with level of IQ and hemisphere of focus. Results: The group, as a whole, exhibited no clinically significant changes in overall IQ, F(1, 19) = .004, p = .948, Verbal IQ, F(1, 20) = .008, p = .929, or Nonverbal IQ, F(1, 18) = 1.973, p = .177. Among the individual cognitive variables, statistically significant improvement on measures of serial digit repetition were revealed, F(1, 13) = 5.140, p = .041. All other variables remained stable. On the behavioral factors, trends were noted for improvements in parent reported attention, F(1,8) = 3.736, p = .089, social withdrawal, F(1,5) = 4.428, p =.089, and emotional distress, F(1,8) = 3.471, p .099. Further investigations revealed a significant interaction between verbal memory outcome and level of IQ, F(1,9) = 5.953, p = .037. A significant interaction between nonverbal intelligence and side of surgery was also discovered, F(1,17) = 8.966, p = .008. Some trends suggested greater improvements in overall IQ, F(1,18) = 3.415, p = .081, and parent reported attention, F(1,6) = 2.394, p = .173, for children with low IQ. Conclusions: Results of the present investigation reveal generally stable cognitive outcomes in children who underwent nonlesional extratemporal lobe epilepsy surgery. Children either experienced stable cognitive performance, or they demonstrated improvements in attention and nonverbal reasoning. Children with low IQ prior to surgery appeared to experience the greatest gains, particularly in long-term verbal memory. A number of noteworthy trends are apparent that suggest improvements in behavioral functioning, but, given the small sample sizes, further investigation would be necessary to confirm their significance.