title: Magnetoencephalography and diffusion tensor imaging in gelastic seizures secondary to a cingulate gyrus lesion.
abstract: Gelastic seizures are relatively uncommon and rarely observed secondary to frontal lobe lesions. This report presents magnetoencephalography (MEG) and diffusion tensor imaging (DTI) findings in an adolescent with gelastic seizures secondary to a left anterior cingulate gyrus lesion. Ictal scalp video EEG showed bilateral frontal 4 Hz theta discharges. Interictal EEG showed left fronto-temporal spikes or sharp waves. Interictal MEG showed spike sources over bilateral temporal regions. DTI and tractography delineated slightly shifted corpus callosum posterior to the lesion, unaffected uncinate and inferior longitudinal fasciculi. The patient became seizure free for 12 months after surgical excision of a pleomorphic xanthoastrocytoma in the left anterior cingulate region. In our patient, MEG and EEG did not localize the deep-seated epileptogenic zone. The combination of DTI and neurophysiologic studies, however, possibly disclosed neuronal connections within the epileptic network and indicated that epileptic discharges propagated via the uncinate fibers from the primary epileptogenic zone in the anterior cingulate region to the mesial temporal region in this case with gelastic seizures secondary to a cingulate lesion.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
authors.forename: Ismail S
authors.initials: IS
authors.lastname: Mohamed
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
authors.forename: Manohar
authors.initials: M
authors.lastname: Shroff
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Donner
authors.forename: James
authors.initials: J
authors.lastname: Drake
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D006179:Gyrus Cinguli / Q000473:pathology / Q000601:surgery; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009412:Nerve Fibers / Q000473:pathology; D013826:Theta Rhythm