title: Neurophysiologic findings of neuronal migration disorders: intrinsic epileptogenicity of focal cortical dysplasia on electroencephalography, electrocorticography, and magnetoencephalography.
abstract: We define specific neurophysiologic characteristics for focal cortical dysplasia, a neuronal migration disorder. We reviewed data from published reports and our patients with focal cortical dysplasia. Our patients underwent preoperative scalp video-electroencephalography (EEG), magnetic resonance imaging (MRI), magnetoencephalography, and intraoperative or extraoperative electrocorticography monitoring. Scalp EEG showed trains of rhythmic epileptiform spike or sharp waves. Positive spikes correlated with early seizure onset, MRI lesion around the rolandic fissure, hemiparesis, and a less favorable outcome. Interictal electrocorticography showed continuous epileptogenic discharges: repetitive electrographic seizures and bursting discharges or continuous or quasicontinuous rhythmic spiking. Ictal electrocorticography showed paroxysmal fast and/or repetitive spiking. Magnetoencephalography showed clustered spike sources within and extending from the lesion. Cortical stimulation gave more frequent, lower-threshold afterdischarges and higher-threshold primary motor function. Focal cortical dysplasias are highly and intrinsically epileptogenic. For surgical seizure control, EEG, electrocorticography, and magnetoencephalography must delineate the intrinsic epileptogenic zone within and extending from the focal cortical dysplasia identified by MRI.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada. hiroshi.otsubo@sickkids.ca
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
authors.forename: Koji
authors.initials: K
authors.lastname: Iida
authors.forename: Makoto
authors.initials: M
authors.lastname: Oishi
authors.forename: Chiyuki
authors.initials: C
authors.lastname: Okuda
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pang
authors.forename: Shelly K
authors.initials: SK
authors.lastname: Weiss
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
authors.forename: Sylvester H
authors.initials: SH
authors.lastname: Chuang
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
mesh_terms: D001931:Brain Mapping; D002465:Cell Movement / Q000502:physiology*; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000503:physiopathology*; D002648:Child; D004558:Electric Stimulation; D004569:Electroencephalography; D004594:Electrophysiology; D004828:Epilepsies, Partial / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D009474:Neurons / Q000502:physiology*; D012189:Retrospective Studies; D014402:Tuberous Sclerosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D014741:Video Recording