Partial seizures are associated with early increases in signal complexity.
Christophe C Jouny1, Gregory K Bergey, Piotr J Franaszczuk
1Johns Hopkins University School of Medicine, Department of Neurology - Epilepsy Research Laboratory, Meyer 2-147, 600 N Wolfe Street, Baltimore, MD 21287, USA. cjouny@jhmi.edu
Summary
Partial onset seizures show an early increase in signal complexity, measured by Gabor atom density (GAD). This finding challenges previous beliefs and is consistent across different seizure origins.
Area of Science:
- Neuroscience
- Epilepsy Research
- Signal Processing
Background:
- Partial seizures are commonly thought to involve low EEG signal complexity due to increased neural synchrony.
- Existing methods may not fully capture the dynamic changes in signal complexity during seizure onset.
Purpose of the Study:
- To assess the signal complexity of epileptic seizure onsets using novel quantitative measures.
- To investigate the relationship between seizure onset and signal complexity changes.
Main Methods:
- Analysis of 339 partial seizures from 45 patients using intracranial electrode arrays.
- Application of the Gabor atom density (GAD) measure to quantify signal complexity.
- Segmentation to determine the timing and amplitude of GAD changes relative to seizure electrographic onset.
Main Results:
- A significant increase in GAD complexity was observed in 97% of analyzed seizures (319 out of 339).
- GAD increases occurred within seconds of seizure onset and were localized to channels near the seizure focus.
- The observed complexity increase was consistent across mesial temporal, neocortical temporal, and extra-temporal seizure origins.
Conclusions:
- Partial onset seizures are characterized by an early and significant increase in signal complexity, as measured by GAD.
- This complexity increase is a common feature of partial seizures, regardless of their origin in the brain.
- The findings suggest a consistent underlying dynamic in partial seizure evolution.
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