[Use of functional MRI in epilepsy]

For the purpose of examining pathophysiological mechanisms of a memory function in epileptic patients or an utility of fMRI for a presurgical assessment in neurosurgical treatment of epilepsy, activated areas in fMRI during verbal or visual memory task were investigated in patient group of temporal lobe epilepsy and normal subject group. Patient group of temporal lobe epilepsy consisted of 7 cases, of which 3 and 3 cases had left and right temporal foci, respectively, except 1 case having undetermined laterality of temporal foci. Normal subjects were 16 cases. All the epileptic and normal subjects were right-handed except for 1 lefty normal subject. Verbal memory tasks were composed of covert and overt recall tasks of 10 words given auditorily, while visual ones were recall tasks of 6 figures given visually. Eventually, in normal subjects, the left side-dominant medial frontal lobes including the superior frontal and anterior cingulate gyri were mainly activated in fMRI during the covert recall tasks of verbal memory, while the left side-dominant inferior frontal and precentral gyri as the motor language areas were chiefly activated in addition to the medial frontal lobe during the overt recall tasks. Further, the bilateral occipital lobes were activated in fMRI during the recall tasks of visual memory. Also in patient groups of temporal lobe epilepsy, the activated areas in fMRI during these tasks were the same as in normal subject group, regardless of the laterality of epileptic temporal foci. These results suggest that fMRI is useful for the determination of the lateralization of the cerebral hemisphere contributing to verbal memory function and therefore for the presurgical assessment of memory function in neurosurgical treatment of epilepsy.