Onset and propagation of spike and slow wave discharges in human absence epilepsy: A MEG study.
OBJECTIVE
A nonlinear association and a source localization technique were used to describe the onset and propagation of spike-and-slow-wave discharges (SWDs) in children with absence seizures. Previous studies have emphasized a leading cortical role in the generation of absence seizures in genetic epileptic rats.


METHODS
Synchronization between all magnetoencephalography (MEG) sensor-couples before and during SWDs in five patients was investigated over time. A source localization [beamformer, SAM(g(2))] technique was used to find brain regions associated with the origin of the spikes of the SWDs.


RESULTS
The onset of SWDs was characterized by high associations at left and right frontal regions. An alternating pattern of high synchronization was found during trains of SWDs: generalized during the wave and localized during the spike; the origin of the spike was different from the onset of SWDs, more frontal lateral and medial parietal. The localization of this latter region was confirmed with SAM(g(2)).


CONCLUSIONS
The outcome of the nonlinear association techniques demonstrated that SWDs have a local cortical onset, whereas the association and beamformer technique support a local or even a focal cortical involvement in the occurrence of the spike in a train of SWDs. In all, the cortex contains local frontal and parietal sites relevant before the onset of the generalized pattern of SWDs and other ones that might contain the driving force behind the spike in trains of 3-4 Hz SWDs.
Westmijse
Inge
I
Donders Centre for Cognition, Radboud University Nijmegen, The Netherlands.
Ossenblok
Pauly
P
Gunning
Boudewijn
B
van Luijtelaar
Gilles
G
D000293:Adolescent; D000818:Animals; D001931:Brain Mapping / Q000706:statistics & numerical data; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000706:statistics & numerical data; D004832:Epilepsy, Absence / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D017711:Nonlinear Dynamics; D010296:Parietal Lobe / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains; D012815:Signal Processing, Computer-Assisted