Frontal Localization of Absence Seizures Demonstrated by Ictal Positron Emission Tomography

Generalized absence seizures are rarely reported to originate from one frontal lobe. We report an 8-year-old girl with atypical absence seizures demonstrated to be of right frontal origin by ictal positron emission tomography (PET). She had a congenital left hemiparesis and intractable seizures since age 3, and was referred for epilepsy surgery. During electroencephalography-video monitoring numerous episodes of atypical absence seizures were recorded in association with generalized 3- to 3.3-Hz spike-and-wave discharges by EEG. PET was performed with simultaneous EEG recording. Six typical seizures occurred during the fluorodeoxyglucose (FDG) uptake period. The PET scan demonstrated marked increased FDG uptake in right frontal region. Partial seizures of frontal lobe origin can manifest themselves as atypical absence seizures, with generalization based on secondary bilateral synchrony. In patients with frequent seizures the frontal seizure origin may be demonstrated noninvasively with functional imaging using PET or single-photon emission computed tomography.