INDIVIDUAL PREDICTION OF CHANGE IN DELAYED RECALL OF PROSE PASSAGES AFTER LEFT-SIDED ANTERIOR TEMPORAL LOBECTOMY

Prognostic variables for individual memory outcome after left anterior temporal lobectomy (ATL) were studied in 27 patients with refractory temporal lobe epilepsy. The difference between pre-and postoperative p erformance in the delayed recall of two prose passages (Story A and B) from the Wechsler Memory Scale served as measure of postoperative mem ory change. Fifteen independent clinical, neuropsychological, and elec trophysiological variables were submitted to a multiple linear regress ion analysis. Preoperative immediate and delayed recall of story conte nt and right hemisphere Wada memory performance for pictorial and verb al items explained very well postoperative memory changes in recall of Story B. Delayed recall of Story B, but not of Story A, had high conc urrent validity to other measures of memory. Patients who became seizu re-free did not differ in memory change from patients who continued to have seizures after ATL. The variables age at epilepsy onset and prob able age at temporal lobe damage provided complementary information fo r individual prediction but with less effectiveness than Wada test dat a. Our model confirmed that good preoperative memory functioning and i mpaired right hemispheric Wada memory performance for pictorial items predict a high risk of memory loss after left ATL. The analyses demons trate that the combination of independent measures delivers more infor mation than Wada test performance or any other variable alone. The sug gested function can be used routinely to estimate the individual sever ity of verbal episodic memory impairment that might occur after left-s ided ATL and offers a rational basis for the counseling of patients.