Abstract
Ten long-term outpatients having temporal lobe epilepsy and unilateral epileptic focus in scalp EEG were studied in interictal periods using1H magnetic resonance spectroscopy (MRS). The N-acetylaspartate (NAA)/creatine plus phosphocreatine (Cr) ratio in the mesial temporal region ipsilateral to the epileptic focus was signifi-cantly decreased in patients, compared to that of control subjects, which reflected neuronal loss or neuronal dysfunction. NAA/Cr ratios were also decreased in the temporal region contralateral to the epileptic focus in 6 out of 10 patients, although less than those in the ipsilateral region. The group with decreased levels of NAA in only the right epileptic focus showed less severity of symptoms related with temporal lobe epilepsy, such as complicated seizure pattern, efficacy of antiepileptic drugs, psycho-logical disturbances, social adaptation and prognosis, than groups with a bilateral decreases in NAA levels. These symptoms were particularly worse in the group with left EEG focus and NAA levels that were decreased not only in the left mesial temporal region ipsilateral to the epileptic focus but also in the contralateral temporal region. H MRS study demonstrated that laterality and bilateral decrease in NAA/Cr ratios have a close relation with clinical symptoms, course and prognosis in temporal lobe epilepsy.
