Interictal 18FDG PET findings in temporal lobe epilepsy with déjà vu

The authors studied the functional anatomy of the déjà vu (DV) experience in nonlesional temporal lobe epilepsy (TLE), using interictal fluorine-18 fluorodeoxyglucose PET in 14 patients with and 17 patients without DV. Several clinical conditions, such as age at PET study, side of ictal onset zone, and dominance for language, were no different between the two groups. The patients with DV showed significant relative reductions in glucose metabolism in the mesial temporal structures and the parietal cortex. The findings demonstrate that ictal DV is of no lateralizing value. They further suggest that temporal lobe dysfunction is necessary but not sufficient for the generation of DV. Extensive association cortical areas may be involved as part of the network that integrates this distinct experience.