Different neuronal networks are associated with spikes and slow activity in hypsarrhythmia.
OBJECTIVE
West syndrome is a severe epileptic encephalopathy of infancy characterized by a poor developmental outcome and hypsarrhythmia. The pathogenesis of hypsarrhythmia is insufficiently understood.


METHODS
We investigated eight patients with infantile spasms and hypsarrhythmia (group I) and 8 children with complex partial seizures (group II) using simultaneous recordings of electroencephalogram (EEG) and functional MRI. Hemodynamic responses to epileptiform discharges and slow wave activity (EEG delta power) were analyzed separately.


RESULTS
In group I (mean age, 7.82 +/- 2.87 months), interictal spikes within the hypsarrhythmia were associated with positive blood oxygenation level-dependent (BOLD) changes in the cerebral cortex (especially occipital areas). This was comparable with cortical positive BOLD responses in group II (mean age, 20.75 +/- 12.52 months). Slow wave activity in group I correlated significantly with BOLD signal in voxels, which were localized in brainstem, thalamus, as well as different cortical areas. There was no association between BOLD effect and EEG delta power in group II. Moreover, as revealed by group analysis, group I differed from group II according to correlations between BOLD signal and slow wave activity in putamen and brainstem.


CONCLUSIONS
This study demonstrates that multifocal interictal spikes and high-amplitude slow wave activity within the hypsarrhythmia are associated with the activation of different neuronal networks. Although spikes caused a cortical activation pattern similar to that in focal epilepsies, slow wave activity produced a hypsarrhythmia-specific activation in cortex and subcortical structures such as brainstem, thalamus, and putamen.
Siniatchkin
Michael
M
Department of Neuropediatrics, Christian-Albrechts-University of Kiel, Kiel, Germany. m.siniatchkin@pedneuro.uni-kiel.de
van Baalen
Andreas
A
Jacobs
Julia
J
Moeller
Friederike
F
Moehring
Jan
J
Boor
Rainer
R
Wolff
Stephan
S
Jansen
Olav
O
Stephani
Ulrich
U
D017668:Age of Onset; D001479:Basal Ganglia / Q000503:physiopathology; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D001933:Brain Stem / Q000503:physiopathology; D002540:Cerebral Cortex / Q000503:physiopathology; D002675:Child, Preschool; D003700:Delta Rhythm / Q000706:statistics & numerical data; D004569:Electroencephalography / Q000706:statistics & numerical data*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008991:Monitoring, Physiologic / Q000706:statistics & numerical data; D009434:Neural Pathways / Q000503:physiopathology; D009778:Occipital Lobe / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D013036:Spasms, Infantile / Q000175:diagnosis / Q000503:physiopathology*; D013788:Thalamus / Q000503:physiopathology
D010100:Oxygen