Coexistence of symptomatic focal and absence seizures: video-EEG and EEG-fMRI evidence of overlapping but independent epileptogenic networks.
The distinction between typical absences and hypomotor seizures in patients having frontal lesions is difficult. In focal epilepsy, generalized-like interictal discharges can reflect either a coexistent generalized epileptic trait or a secondary bilateral synchrony. Using combined measures of the EEG and blood oxygenation level dependent (BOLD) activity, we studied a 50-year-old patient with both absence-like and symptomatic focal motor seizures. Focal activity induced activation in the lesional area and deactivation in the contralateral central cortex. Generalized spike-and-wave discharges (GSWDs) resulted also in perilesional activation, and multifocal symmetrical cortical and thalamic activations, and deactivation in associative cortical areas. Although the central cortex was involved during both types of epileptic activity, electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) revealed distinct neuronal networks at the time of the focal or generalized discharges, allowing a clear-cut differentiation of the generators. Whether the patient had distinct epileptic syndromes or distinct electrographic patterns from the lesional trigger remains debatable.
Chassagnon
Serge
S
Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
Hawko
Colin S
CS
Bernasconi
Andrea
A
Gotman
Jean
J
Dubeau
François
F
D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D015897:Comorbidity; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D004832:Epilepsy, Absence / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D054220:Malformations of Cortical Development / Q000453:epidemiology / Q000503:physiopathology; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D010100:Oxygen / Q000097:blood
D010100:Oxygen