![]() The intravenously injected dose of FDG was 250 MBq. All patients gave their written informed consent to participate in comprehensive studies for epilepsy surgery.Īll patients underwent interictal 18FDG PET brain scans using an ECAT 951R scanner (Siemens CTI Knoxville, TN) while on full antiepileptic medication after a 6-hour fast. None of the patients had any neurological condition other than epilepsy, or any acute or chronic medical illness, at the time of the PET study. Additional selection criteria were 1) unilateral temporal onset of the habitual seizures, so that a correlation of the occurrence of the symptom and the side of the epileptogenic focus could be established, and 2) absence of a mass lesion on brain magnetic resonance imaging (MRI) to eliminate any significant deafferentation effect that could contaminate the 18FDG PET findings. The diagnosis of TLE was based on historical evidence and concordant interictal and ictal video-EEG findings. Seventeen patients with TLE who did not report DV were randomly selected from the same series for comparison. Patients who had a past history of DV but lacked the experience during the period prior to the PET scan, as well as those with poorly defined auras of strangeness, were not included in the study. Along with other information, the early clinical ictal characteristics of the habitual seizures, including the presence of auras and their exact content, are systematically sought by direct questioning of the patients and their relatives by one of the authors (C.E.P.), and the relevant information is entered into a database specifically designed for this purpose.įourteen patients with TLE who reported DV as a habitual ictal experience were consecutively selected from this database. The scheme of preoperative investigation and management that is used in our Epilepsy Surgery Centre 17 includes obtaining a clinical history. Thomas' Clinical PET Centre between 19 as part of a comprehensive preoperative evaluation. The subjects of this study were selected from a large series of surgical candidates with medically intractable epilepsy who had interictal 18FDG PET in St. Working from the hypothesis that regional hypometabolism could involve symptomatogenic brain areas, we attempted to gain further insight into the functional anatomy of DV by examining the interictal metabolic features of patients with TLE with and without ictal DV experience. ![]() Interictal studies using fluorine-18 fluorodeoxyglucose positron emission tomography ( 18FDG PET) may demonstrate reduced metabolism in the region of the epileptic focus and surrounding functional disturbance these may be secondary to structural changes or related to interictal and ictal epileptiform discharges, 15, 16 which in turn give rise to ictal symptoms and signs. 12, 13 However, it is uncertain whether temporal lobe disturbance is sufficient and necessary for the generation of DV, since the incidence of the symptom is comparatively low in TLE 14 and it is difficult to evaluate wider cortical regions in TLE by using intracranial recordings. Three possible sites of dysfunction have been proposed on the basis of intracranial electroencephalographic (EEG) monitoring and stimulation studies: the mesial temporal lobe, 5, 9 especially in the nondominant hemisphere 10 the superior lateral temporal cortex 11 and a neuronal network that engages both medial and lateral aspects of the temporal lobe. Previous clinical observations have linked DV to temporal lobe epilepsy (TLE), 5– 10 but the precise origin and cause of the symptom are still controversial. 2, 3 Although DV is probably a universal experience, 4 patients with epilepsy often develop the phenomenon as an ictal symptom in partial seizures. 1 It has been suggested that different mental components such as memory, attention, and perception are associated with this distinct experience. D éjà vu (DV) is defined as any subjectively inappropriate impression of familiarity of a present experience with an undefined past.
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