RELATIONSHIP OF AGE AT ONSET, CHRONOLOGICAL AGE, AND ADEQUACY OF PREOPERATIVE PERFORMANCE TO VERBAL MEMORY CHANGE AFTER ANTERIOR TEMPORAL LOBECTOMY

We examined the relationship of age of onset of epilepsy, chronologica l age at time of operation, and adequacy of preoperative memory perfor mance to pre- to postoperative verbal memory decline. Patients who und erwent left (n = 50) or right (n = 51) anterior temporal lobectomy (AT L) were administered tests of verbal episodic (list learning, paragrap h recall) and semantic memory (visual naming, vocabulary), both preope ratively and 6 months postoperatively. As a group, left ATL patients s howed the classic selective decrease on measures of episodic but not s emantic memory. However, examination of episodic memory outcome showed considerable individual variability. Stepwise regression analyses ind icated that both later age at onset and older chronologic age were sig nificant and selective predictors of episodic memory decrease for left ATL patients. Adequacy of preoperative memory performance was a nonsp ecific predictor, associated with decrease in postoperative memory per formance for both left and right ATL patients and for multiple types o f memory indices. The clinical and theoretical implications are discus sed.