Abstracts

Rationale: Temporal lobe resection benefts many patients with refractory temporal lobe epilepsy, however may be complicated by memory impairments typically of verbal memory following temporal lobe resection. The Wada test is widely used procedure to detect deminant hemispere as well as predict postoperative memory deficits, however, has a number of disadvantages, notably the fact that it is an expensive and invasive procedure. Functional MRI(fMRI) has potential for replacing Wada test and providing additional memory function data. We examined whether Wada test can be replaced by fMRI to detect dominant hemisphere. Methods: Using 3.0T-functional MRI(fMRI), we tried to preoperatively detect dmominant hemisphere in the patient with mesial temporal lobe epilepsy(MTLE). Five patients(median age48.6; range 20-51 years; one left-handed) with mesial TLE(three had left MTLE) underwent fMRI session each consisting of 16 words. Patients were instructed to memorize the words coming from headphone during scanning. Just after each session, patients were given memory test for the words recieved in the scanner and to attempt to recall as many of the words as possible. All data were analyzed using Statistical Parametric Mapping software(SPM2). These data obtained from fMRI was compared with the result of Wada test. Results: Two of five patients showed left mesial temporal lobe activation, two patients showed bilateral mesial temporal lobe activation, and one patient showed right side activation. On the other hand, Wada test revealed left hemisphere dominance in all but one patient. This patient was left-handed and confirmed to be right hemisphere dominant for language on both fMRI and the Wada test. Conclusions: The fMRI may be an useful non-invasive test for detecting dominant hemisphere contributing memory function. Language fMRI might reduce the necessity of the Wada test for language lateralization, especially in TLE.