A-080 Prediction Model for Verbal Memory Decline in Different Epilepsy Surgery Procedures: Temporal Lobectomy vs. Amygdalohippocampectomy

Abstract

Abstract Objective Mathematical models predicting risk of verbal memory decline after resective epilepsy surgery have been developed for patients undergoing temporal lobectomies. This study was undertaken to determine if application of the Stroup memory loss prediction model was as accurate in foreseeing verbal memory decline after temporal lobectomy as in the less invasive selective amygdalohippocampectomy procedure. Method This retrospective study examined the verbal memory performances of 40 left temporal lobectomy (ATL), and 16 left subtemporal approach selective amygdalohippocampectomy (SA-H), patients before and after epilepsy surgery using word list learning (Rey Auditory-Verbal Learning Test, Buschke Selective Reminding Test) and story memory (WMS Logical Memory) tests. Patients were assigned to one of four groups using the Stroup multiple regression equation: Minimal Risk (61% risk). To classify memory decline in individual patients, a pre-to-post surgery decrease of > 1 SD on at least one memory test constituted memory decline. Results The prediction model accurately classified 82% (9/11) of ATL, and 75% (3/4) of SA-H, High Risk patients. Verbal memory loss was higher among ATLs than SA-Hs in the Moderate Risk (87% vs. 18%) and Low Risk (71% vs. 0%) groups. Conclusion The Stroup verbal memory loss risk model under-predicted memory loss among temporal lobectomy patients (71% of Low Risk patients showed memory decline) and over-predicted memory loss among selective amygdalohippocampectomy patients (only 18% of Moderate Risk patients showed memory decline). Results should be considered preliminary due to methodological limitation including small Ns and unequal sample sizes.