PREDICTION OF VERBAL MEMORY LOSS IN INDIVIDUALS AFTER ANTERIOR TEMPORAL LOBECTOMY

Purpose: Decreased memory function represents the area of greatest neu ropsychological morbidity after anterior temporal lobectomy (ATL), par ticularly for left ATL candidates. We wished to identify easily derive d demographic and neuropsychological predictors of risk of pre- to pos toperative memory decline using only information available preoperativ ely. Methods: We assessed decline in memory as measured by the Califor nia Verbal Learning Test (CVLT) by deriving multiple regression equati ons using the following measures as independent variables: age at onse t, chronological age at time of surgery, sex, Full Scale IQ (FSIQ), le vel of education, and preoperative memory scores. In all, 203 patients (93 males, 110 females), undergoing ATL (107 left, 96 right) with pre operative and 6-month postoperative testing, were examined. Results: T he combination of age, FSIQ, sex: side of surgery and preoperative sco re was highly predictive (p-values < 0.0001) of postoperative memory s cores, Higher postoperative scores were associated with higher preoper ative score, younger chronological age, higher FSIQ, female sex: and r ight side of resection, Reliable change index (RCI) values were used t o estimate meaningful decline on the total score across five trials. L ogistic regression analysis showed preoperative score and age to be pr edictors of RCI decline for left-sided resections, Sensitivity of decl ine (greater than or equal to 90th centile RCI) prediction was 56%, an d specificity was 95%. Validation in 30 patients from a separate popul ation of patients undergoing left ATL produced similar figures. Conclu sions: The derived regression equations can accurately predict verbal memory decline on a list-learning task in similar to 50% of individual patients undergoing ATL, and false-positive prediction errors are ver y rare.