Temporal lobectomy in children: cognitive outcome

Object. The authors sought to determine the impact of early temporal lobect omy (in patients younger than age 17 years) on intellectual functioning. Th e efficacy of temporal lobectomy for treating seizures is well established and the procedure is becoming more acceptable as a treatment for children w hose seizures are intractable. However, cognitive outcomes of temporal lobe ctomy in children and adolescents are largely unreported. The present study takes advantage of a unique multicenter collaboration to examine retrospec tively intellectual functioning in a large sample of children who underwent temporal lobectomy. Methods. intellectual functioning wets assessed before and after temporal l obectomy for treatment of medication-resistant seizures in 82 patients at e ight centers of epilepsy surgery. All children underwent standard presurgic al examinations, including electroencephalography-video monitoring, magneti c resonance (MR) imaging, and neuropsychological testing, at their respecti ve centers. Forty-three children underwent left temporal lobectomy and 39 underwent rig ht temporal lobectomy. For the entire sample, there were no significant dec lines in intelligence quotient (IQ) following surgery. Children who underwe nt left temporal lobectomy demonstrated no significant loss in verbal intel lectual functioning and improved significantly in nonverbal intellectual fu nctioning. Children who underwent right temporal lobectomy did not demonstr ate significant changes in intellectual functioning. Although group scores showed no change in overall IQ values, an analysis of individual changes re vealed that approximately 10% of the sample experienced a significant decli ne and 9% experienced significant improvement in verbal functioning. Signif icant improvement in nonverbal cognitive function was observed in 16% of th e sample and only 2% of the sample showed significant declines. Risk factor s for significant decline included order patient age at the time of surgery and the presence of a structural lesion other than mesial temporal scleros is on NIR imaging. Conclusions. The present study provides preliminary data for establishing t he risk of cognitive morbidity posed by temporal lobectomy performed during childhood. With respect to global intellectual functioning, a slight impro vement was significantly more likely to occur than a decline. However, ther e were several patients in whom significant declines did occur. It will be necessary to study further the factors associated with such declines, in ad dition, further study of more specific cognitive functions, particularly me mory, is needed.