Difference of EEG Dipole Propagation Between Spikes with Myoclonic Jerks and Without Jerks in Patients with Epilepsia Partialis Continua
Abstract number :
3.108
Submission category :
Year :
2000
Submission ID :
1724
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Ayako Ochi, Hiroshi Otsubo, Shiro Chitoku, Amrita Hunjan, James T Rutka, Sylvester H Chuang, Ken-ichi Kamijo, Toshimasa Yamazaki, O. Carter Snead, The Hosp for Sick Children, Toronto, ON, Canada; Fundamental Research Lab, NEC Corp, Tsukuba, Japan.
RATIONALE: Dipole localizations of epilepsia partialis continua (EPC) have been reported to be localized in pre-central gyrus using electroencephalography (EEG) and magnetoencephalography (MEG). We applied moving dipole modeling to delineate electrophysiological mechanism of myoclonic jerks in EPC. We studied difference of dipole propagation between EEG spikes with myoclonic jerks and without jerks in two patients with EPC. METHODS: Two patients with EPC (patient A, 12 year old boy with left centro-parietal cortical dysplasia; patient B, 7 year old girl with right hemispheric Rasmussen's syndrome) were studied. Video EEG telemetry with 19 scalp electrodes and electromyography of the wrist extensor muscle that was contra-lateral to the brain lesion were simultaneously recorded. Sampling rate was 200 Hz. We selected spikes with and without myoclonic jerks by visual inspection, analyzed the dipole localizations using a single moving dipole method on a 3-shell spherical model, and overlaid the resultant data onto a co-registered MRI. We selected dipoles with goodness of fit >95%. RESULTS: The dipoles of the spikes with jerks were concentrated around the pre-central area, whereas those without jerks showed diffuse distribution, especially anterior to posterior around the central area. The distance between the dipole positions with jerks in each successive time point was smaller than that without jerks. The dipole moment with jerks was bigger than that without jerks in patient A. In patient B, although the dipole moment with jerks was smaller than that without jerks, orientation of the dipoles with jerks was more stable than that without jerks. CONCLUSIONS: The dipole positions of the spikes with myoclonic jerks were more concentrated and stable on motor cortex compared to those without jerks. The analysis of dipole moment of epileptic discharges to produce the myoclonic jerks suggested two possible mechanisms, 1) a stronger stimulation, 2) consecutive stimulations at the same area in the precentral region.