Memory after Temporal Lobectomy

Abstract

Epilepsy is a common neurological disorder. Its mean prevalence is about 7 per 1000 people of the general population. Apart from drug therapy, recent advances in diagnostic technology and surgical techniques have led to increasing use of surgical treatment for certain specific epileptic syndromes that have responded poorly to drug therapy. Possible memory decline induced by epilepsy surgery becomes a major concern. This paper reviews the material-specific ipsilateral memory deficit and contralateral improvement after temporal lobectomy. According to the literature, the left and right mesial temporal systems process different types of material-specific information, mostly in accordance with the pattern of cerebral language dominance. In general, the temporal lobe of the dominant hemisphere is associated with verbal memory and that of the non-verbal memory. While surgical treatment may induce memory deficits related to the destruction of the ipsilateral mesial temporal system, improvement in memory functioning is observed in the contralateral hemisphere. The impact of factors, such as surgical procedure, focus of neuropsychological evaluation, timing of post operative measures of cognitive functions, and demographic variability of the surgical candidates, on the findings of the studies on memory after temporal lobectomy are reviewed.