Effect of Material-specificity on the Wada Memory Test in Medial Temporal Lobe Epilepsy with Hippocampal Sclerosis

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1 Effect of Material-specificity on the Wada Memory Test in Medial Temporal Lobe Epilepsy with Hippocampal Sclerosis Seong-Ho Park, M.D., Hyunwoo Nam, M.D., Sang-Kun Lee, M.D., Kwang-Woo Lee, M.D., Jae-Kyu Roh, M.D. Department of Neurology, College of Medicine, Seoul National University Backgrounds : The Wada test is a useful method in predicting the laterality of a epileptogenic zone. However, past research reveals that material specificity has an influence on the lateralization We examined the material-specificity of memory and its change in epileptic patients to discover reasonable items on the Wada test for the proper lateralization of the epileptogenic zone. Methods : We analyzed 45 patients with video-eeg-confirmed medial temporal lobe epilepsy (mtle) and definite hippocampal atrophy by an MRI. Eight items were presented during the Wada test including 3 common objects, 1 geometric object, 1 color, 1 word, 1 phrase, and 1 math expression. We checked recognition memory after recovery of hemiparesis and normalization of EEG. Results : For the right mtle group, recognition memory following a right hemisphere injection was significantly better than a left hemisphere injection for all categories. For the left mtle group, a significant difference of scores was found for the left versus right hemisphere injection for common objects. When injected to the left hemisphere, all the items helped lateralization, but when injected to the right hemisphere, a phrase did not help with lateralization. Conclusions : Items with strong unilateral encodings do not help lateralizing the epileptogenic zone. J Kor Neurol Ass 17(4):486~49, 1999 Key Words : Wada Test, Material Specificity, Medial Temporal Lobe Epilepsy Seong-Ho Park, M.D. 486 Copyright 1999 by the Korean Neurological Association

2 Figure 1. Items presented to the patients during Wada memory test. Set 1 is presented during amobarbital is injected to the left hemisphere and set 2 is presented during it is injected to the right hemisphere. J Kor Neurol Ass / Volume 17 / July,

3 R L RmTLE LmTLE Figure 2. Percentage of correct response in RmTLE group. Memories are better in the left hemisphere than in the left in all items(p<.1). R : function of right hemisphere L : function of left hemisphere R L Figure 4. Percentage of correct response of each mtle group when injected to the left hemisphere. All the items show statis - tically significant difference between two groups(p<.5). Common Obj : common object Geo : geometric object Math Exp : math expression RmTLE LmTLE Figure 3. Percentage of correct response in LmTLE group. Statistical significance is present between two hemispheres on in the common object(p<.5) R : function of right hemisphere L : function of left hemisphere Common Obj : common object Geo : geometric object Math Exp : math expression Figure 5. Percentage of correct response of each mtle group when injected to the right hemisphere. All the items except phrase show statistically significant difference between two groups(p<.5). 488 J Kor Neurol Ass / Volume 17 / July, 1999

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