Abstracts

Rationale: Investigations into the ability of Wada testing to accurately predict memory loss after anterior temporal lobectomy have yielded contradictory results. Although conflicting results are secondary to a variety of methodological dissimilarities across studies, important factors include inadequate sample sizes and differences in how Wada memory was assessed. To address these deficiencies, we evaluated the memory test performances of temporal lobectomy patients before and after surgery after classifying their risk for memory loss using the most common Wada memory assessment method; viz., where a predetermined number of discrete stimuli were presented during the period of drug effect, and then memory for the stimuli was assessed after hemispheric anesthetization resolved. Methods: 94 (54 left, 40 right) adult temporal lobectomy patients were classified into 1 of 3 risk groups after Wada memory testing in both hemispheres. There were 46 males and 48 females with a mean age of 32.6, 12.3 years of education, FSIQ of 88.17, and seizure duration of 16.8 years. High risk patients (N=48) showed either no, or reversed (contralateral injection > ipsilateral injection), memory asymmetry and also had normal memory after contralateral injection. Mild risk patients (N=25) showed memory asymmetries either in the correct direction (contralateral < ipsilateral) with normal contralateral memory or no asymmetry (<3/8 memory items) but failed both injections. No risk patients (N=21) displayed memory asymmetries in the correct direction and failed contralateral injection. Pre- and post-surgical verbal and visuospatial neuropsychological memory testing was conducted using the Selective Reminding Test (SRT), WMS Logical Memory (LM), WMS Paired Associate Learning (PA), WMS Faces, and Rey Complex Figure delayed recall (RCF).