Effects of left temporal lobectomy and amygdalohippocampectomy on memory

This study examined the effects of left (dominant) temporal lobe surgery on verbal and visual memory in 38 patients with temporal lobe epilepsy. Twenty-five patients had anterior temporal lobectomy (ATL) and 13 had selective amygdalohippocampectomy (AH). All were administered the Rey Auditory Verbal Learning Test and a Complex Figure Test preoperatively and 1 year after surgery. ATL resulted in better seizure control overall. The ATL group as a whole showed a greater postoperative decline of their verbal memory than the AH group. A closer examination of the ATL patients showed there was a subgroup (n = 11) with better preoperative memory functioning that had the most significant decline. In contrast, only three patients in the AH group had better preoperative memory, and the majority (n = 10) matched the 'memory impaired' ATL patients. The changes in memory performance of the 'memory impaired' ATL and AH patients did not reach statistical significance. Postoperatively all patient groups improved in their verbal fluency.