B – 7 WMS Verbal and Nonverbal Tasks as a Predictor of Performance during the Wada Procedure

Abstract Objective Material specificity of memory tasks is useful for lateralizing cerebral dysfunction. Recent Wada studies raise questions regarding strict laterality effects of these stimuli. This exploratory study utilizes baseline performance on material specific memory measures and Wada performance to further examine these effects. Method 26 adults with refractory complex partial epilepsy (10 right-onset; 15 left) completed neuropsychological evaluations, including WMS Logical Memory Immediate (LM1) and Delay (LM2) and Visual Reproductions Immediate (VR1) and Delay (VR2) subtests. Wada testing included recognition recall of 8 nameable objects, 6 printed words, and 4 abstract designs. Linear regressions assessed how much variance WMS subtests accounted for in Wada tasks. Also, laterality scores were calculated by subtracting verbal minus nonverbal WMS scores and left minus right Wada scores. Results With L injection (LI), LM didn’t account for any variance on Wada tasks. With R injection (RI), LM predicted objects (LM1: R2 = 0.415). With LI, VR predicted objects (VR1: R2 = 0.232) and designs (VR1: R2 = 0.183). With RI, VR predicted objects (VR1: R2 = 0.172; VR2: R2 = 0.363), words (VR2: R2 = 0.205), and designs (VR1: R2 = 0.21; VR2: R2 = 0.275). WMS total difference ((LM1-VR1)-(LM2-VR2)) predicted objects with LI (R2 = 0.192). LM2-VR2 difference predicted words with RI (R2 = 0.217) and approached significance with right–left Wada total score difference (R2 = 0.15). Conclusion These data partially support material specificity in the laterality of the memory network. Specifically, verbal material were more strongly lateralized to left-hemispheric functions, whereas nonverbal memory showed bilateral representation.