INTERICTAL METABOLIC ANATOMY OF MESIAL TEMPORAL-LOBE EPILEPSY

Objective.-To examine patterns of temporal and extratemporal regional interictal glucose hypometabolism in individual patients with unilater al mesial temporal lobe epilepsy (TLE). Previous reports disagree on w hich extratemporal areas can be hypometabolic in TLE. Design.-Case ser ies of patients with TLE who underwent interictal fludeoxyglucose F 18 positron emission tomography, compared quantitatively with normal pos itron emission tomography. Setting.-Patients referred for surgical tre atment of medically refractory complex partial seizures. Patients and Other Participants.-Ten normal volunteers; 27 patients with TLE select ed to exclude seizures of bilateral temporal or extratemporal onset. R esults.-Regional hypometabolism occurred in 25 patients. Hypometabolic regions were ipsilateral to seizure onset and included lateral tempor al (in 78% of patients), mesial temporal (70%), thalamic (63%), basal ganglial (41%), frontal (30%), parietal (26%), and occipital (4%). Spe cific patterns of temporal and extratemporal hypometabolism varied con siderably across the TLE group. Conclusions.-Any of the previously rep orted anatomic areas of hypometabolism can occur in individual patient s with TLE. The prevalence of thalamic hypometabolism suggests a patho physiologic role for the thalamus in initiation or propagation of temp oral lobe seizures or in the interictal cognitive dysfunction of TLE.