Spatiotemporal propagation patterns of generalized ictal spikes in childhood absence epilepsy
Vasileios Kokkinos1, Andreas M Koupparis2, Michalis Koutroumanidis3
1Department of Clinical Neurophysiology and Epilepsies, Guy's, St Thomas' and Evelina Hospital for Children, NHS Foundation Trust, London, United Kingdom; Neurophysiology Unit, Department of Physiology, Medical School, University of Patras, Greece.
Insights
Epileptogenic networks in childhood absence epilepsy (CAE) are personalized, showing distinct spike propagation patterns unique to each child. These patterns can transform during seizures, indicating dynamic network interactions.
Area of Science:
- Neuroscience
- Epileptology
- Clinical Neurology
Background:
- Childhood absence epilepsy (CAE) is a common genetic generalized epilepsy.
- Understanding the underlying network dynamics of CAE is crucial for accurate diagnosis and treatment.
- Previous research has focused on generalized EEG patterns, but spatial-temporal dynamics require further investigation.
Purpose of the Study:
- To investigate the spatial distribution and temporal evolution of generalized ictal spikes in typical absences of CAE.
- To identify and characterize distinct spatiotemporal patterns of ictal discharges in CAE patients.
- To explore the concept of personalized epileptogenic networks in CAE.
Main Methods:
- Analysis of video-electroencephalography (EEG) data from twelve children with CAE.
- Identification and marking of ictal spikes during typical absence seizures.
- Clustering, waveform averaging, and spatiotemporal analysis of ictal spikes in 2D electrode space.
Main Results:
- High consistency of spatiotemporal spike patterns within individual patients, but low consistency between patients.
- Identification of three main discharge patterns: anteroposterior propagation, posterioanterior propagation, and frontal/prefrontal confinement.
- Observed transformation of propagation patterns during seizures in 4 patients, with spikes originating fronto-temporally and maximizing frontally.
Conclusions:
- Epileptogenic networks in CAE are personalized and interconnect specific brain areas, not the entire cortex.
- The dynamic transformation of propagation patterns suggests interplay within these networks.
- Findings support the revised concept of ictogenesis and aid in avoiding misdiagnosis of CAE as focal epilepsy.
Objective:
This work investigates the spatial distribution in time of generalized ictal spikes in the typical absences of childhood absence epilepsy (CAE).
Methods:
We studied twelve children with CAE, who had more than two typical absences during their routine video-EEG. Seizures were identified, and ictal spikes were marked over the maximum electronegative peak, clustered, waveform-averaged and spatiotemporaly analyzed in 2D electrode space.
Results:
Consistency of spatiotemporal patterns of ictal spikes was high between the absences of the same child, but low between children. Three main discharge patterns were identified: of anterio-posterior propagation, of posterio-anterior propagation and confined to the frontal/prefrontal regions. In 4 patients, the propagation patterns transformed during the seizure into either a lateralized diminished or a non-lateralized reverse direction form. Most spikes originated fronto-temporaly, all maximized over the frontal/prefrontal electrodes and mostly decayed prefrontaly. In 4 patients, lateralized propagation patterns were identified.
Conclusions:
Ictal spike propagation patterns suggest that epileptogenic CAE networks are personalized, interconnect distal areas in the brain - not the entire cortex - with a tendency to generate bilateral symmetrical discharges, sometimes unsuccessfully. The transformation of propagation patterns during the seizure indicates the existence of dynamic interplay within epileptogenic networks.
Significance:
Our results support the revised concept of ictogenesis of ILAE definition in genetic (also known as idiopathic) generalized epilepsies. Understanding the focal features in CAE avoids misdiagnosis as focal epilepsy and inappropriate treatment.
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