Prediction of verbal memory decline after epilepsy surgery in children: Effectiveness of Wada memory asymmetries

Abstract

Purpose: Differences in Wada memory performance after left and right amobarbital injection are powerful predictors of pre- to postoperative memory change among adult epilepsy patients after anterior temporal lobectomy. It is unknown, however, whether these Wada memory asymmetries apply to children who undergo focal cortical resection or to epilepsy surgery patients who undergo resection outside the temporal lobes. Methods: To investigate these issues, Wada memory asymmetries and pre- to postoperative neuropsychological memory test performances were examined in 132 children who underwent some form of resective epilepsy surgery. Ninety-three (70%) children showed Wada memory asymmetries in the predicted direction (memory after injection ipsilateral to side of surgery better than memory after contralateral injection), and 39 (30%) did not. Results: Children with Wada memory asymmetries showed significant improvement in verbal memory after surgery as compared with children without Wada memory asymmetries who showed significant verbal memory decline. This result was also obtained when individual cases were examined: 77% of children with Wada memory asymmetries in predicted direction showed no verbal memory decline after surgery, whereas 80% of children without asymmetries had lower postoperative verbal memory (passage recall) test scores. Wada memory asymmetries had no value in predicting postoperative changes in visual-spatial memory. Conclusions: Wada memory asymmetries may be used as one of the factors to assess risk for verbal memory decline after epilepsy surgery in children.