Abstracts

Rationale: Intellectual disabilities (ID) and epilepsy often coexist in children, with a seizure prevalence of nearly 40% in those with severe disabilities. The epilepsy in this population is often more severe and refractory to antiepileptic medications. In children with ID, epilepsy surgery may be considered a relative contraindication. Concerns include: 1) decreased probability of good seizure outcome with multi-focal brain involvement in ID and 2) adverse effect on cognitive outcome. The purpose of this study was to assess the prevalence of ID in children who have undergone epilepsy surgery and determine any adverse effects on seizure outcomes and cognition. Methods: A retrospective study was conducted of all patients who underwent epilepsy surgery at Children s Hospital of Alabama from 2006-2010. ID was defined as IQ<70 or severe disabilities rendering testing unsuitable. Resective surgeries included unilobar or multilobar resection or hemispherectomy. Palliative therapy included VNS or corpus callosotomy. Results: Fifty-five children met study criteria. Forty three children had ID (78 %) while 12(22%) had FSIQ >70. Those with ID (21M: 22F; 33 Caucasian) had seizure onset at mean age 2.6 years vs. 6.3 years in the non ID cohort (9M: 3F; 10 Caucasian). An average of 6 AEDs was tried prior to surgery in the ID cohort vs. 5 in the non ID cohort. The mean age at surgery was earlier in the ID group: 9.1 vs. 12.2 years. Pre-surgical IQ testing was performed in 23. Thirteen of 23(57%) had a FSIQ of 50-69 with a mean of 64, while 8 had FSIQ <50 (mean 43). Twelve had an average FSIQ >70, mean 80. Surgical therapy included palliative procedures (23) and resections (23). The ratio of palliative to resective procedures was 17:23 in the ID group vs. 1:10 in the non ID cohort. In the ID group, 17/43(40%) were seizure free, 12/43 (28%) were Engel 2/3 while the remainder had minimal improvement. The non ID group achieved seizure freedom in 7/12 (58%) and Engel 2/3 in 16%. Post-surgical FSIQ (9 of 33 measured) was unchanged except in 2 patients (decrease of 4 and 10 points). Conclusions: The prevalence of ID in refractory epilepsy may reach more than 50% as in our cohort. Age at seizure presentation is earlier in those with ID. Surgical therapies trend toward palliative therapies in children with ID; nevertheless, meaningful seizure outcomes can be achieved. Though there may be a significant FSIQ decrease in the minority, most patients have no significant adverse change in IQ. Post surgical IQ testing is being completed in our patient cohort at this time to further assess any identifiable risk factors.