Language-related cognitive declines after left temporal lobectomy in children.

Presented is a case series demonstrating that clinically significant language-related cognitive declines not detected by intelligence quotient (IQ) testing occur after left temporal lobectomy in school-aged children. In this series, comprehensive preoperative and postoperative neuropsychologic evaluations were completed in eight school-aged patients who underwent temporal lobectomy (five left, three right) for temporal lobe epilepsy. Mean age at surgery was 13 years, 11 months +/- 2 years, 1 month. Testing included measurement of IQ, verbal learning, naming, visual memory, sight word recognition, reading comprehension, and calculation. All five left temporal lobectomy patients demonstrated significant language-related cognitive declines on postoperative neuropsychologic testing, including deficits in verbal IQ (one patient), verbal learning (four patients), naming (one patient), and reading comprehension (one patient). These deficits were clinically evident in four of the five left temporal lobectomy patients, leading to declines in educational performance. IQ testing alone did not reliably identify these deficits. No significant declines were found after surgery in three right temporal lobectomy patients. Average or high preoperative functioning may have predisposed patients to postoperative deficits in this series, whereas magnetic resonance imaging or pathologic abnormalities did not protect against postoperative deficits. Outcome studies of temporal lobectomy in childhood should use comprehensive neuropsychologic testing to identify cognitive deficits.