Abstract

The material-specific memory impairment(MSMI) assumed to be found in temporal lobe epilepsy patients(TLE) provides the rationale to lateralize the seizure focus. Based upon it we tried to determine to what extent memory assessment can lateralize epileptogenic focus in TLE. From patients who were referred for presurgical neuropsychological assessment 41 right and 49 left TLE cases were selected according to inclusion criteria, one of which was that the subject should have hippocampal sclerosis. The results were analyzed in two ways. One way, it was tested whether the performance in Wechsler Memory Scale-Revised(WMS-R) according to memory material interact with the seizure laterality. Another way, it was analyzed to what extent WMS-R subtests discriminate between the left and right TLE. As assumed, memory material did interact with seizure laterality significantly. In verbal memory the left TLE was significantly inferior to the right TLE. But in visual memory tasks the two groups did not perform differently. That is, concerning MSMI hypothesis, only one half(verbal memory deficit in left TLE) was confirmed, but the other half(visual memory deficit in right TLE) was not. Therefore, to the question whether memory assessment can lateralize the seizure focus, the answer is that it can do by half. On the other hand, in the discriminant function analysis, WMS-R diagnosed the focus of seizure laterality correctly in the 73.9% of cases. This level of discrimination is higher than that of previous research. These findings lead to the conclusion that WMS-R, though only half-valid in the perspective of MSMI hypothesis, significantly contributes to the lateralization. At the end, the reasons why impairment of visual memory wasn't found in right TLE were discussed and alternative methods to detect visual memory deficit were listed.