Memory lateralizing values of different stimulus types in Wada test

J Korean Neurol Assoc > Volume 16(6); 1998 > Article

Journal of the Korean Neurological Association 1998;16(6): 844-850.

와다검사에서 자극의 종류에 따른 기억의 편측화 정도

정 기영, 강 연욱, 박 진운, 서 대원, 홍 승봉, 홍 승철*

성균관대학교 삼성서울병원 신경과, 신경외과*

Memory lateralizing values of different stimulus types in Wada test

Ki-Young Jung, Yeonwook Kang, Jin-Woon Park, Dae Won Seo, Seung Bong Hong, Seung Chyul Hong*

Department of Neurology and Neurosurgery*, Samsung Medical Center, Sung Kyun Kwan University

Abstract

Background: We studied the accuracy, lateralization criteria of Wada test in patients with temporal lobe epilepsy(TLE). We also evaluated material specific memory and determined the stimulus which can classify best between right and left TLE among four different types of stimuli.
Methods: We examined Wada memory performance in 33 patients(15 left, 18 right) with TLE who underwent surgery and who were good seizure outcome at least 1 year follow-up. Twelve stimuli consited of figures, written words, geometric designs and real objects were presented after Amytal injection. The recognition memory test was performed at 10 minutes after the injection and hemisphere memory performance of each stimulus and total stimuli were obtained by(number of stimuli recognized / number of stimuli presented x 100%). Classification rate, best stimulus for lateralization, and suitable lateralization criteria were determined by discriminant analysis and Chi-square test. Hemispheric memory difference of each stimulus was analyzed by paired-sample Student's t-test in left temporal lobectomy(LTL) and right temporal lobectomy(RTL) groups.
Results: No significant difference was observed in pre-Wada memory score and in IQ between LTL and RTL group. The classification rate of Wada test in terms of lateralization by discriminant analysis was 81.82%. The accuracy was 75.8% at 10% and 15% lateralization criteria and was 63.6% and 45.5% at 20% and 25% lateralization criteria, respectively. Figure was the most useful among four types of stimuli to classify TLE. Analysis of hemispheric memory according to stimuli revealed that memory difference between hemisphere was significant only for figure in LTL group(p=0.027). In RTL group, all 4 stimulus types had significant hemispheric memory difference (figure, p=0.000; written word, p=0.000; geometric design, p=0.000; real object, p=0.000).
Conclusions: Wada test is a reliable method for lateralizing seizure foci in TLE. To get optimal results, lateralization criteria should be determined by statistica Key Words: Wada test, lateralization, material specific memory, TLE