Delta-gamma phase-amplitude coupling as a biomarker of postictal generalized EEG suppression

• DOI: 10.1093/braincomms/fcaa182
• Publication Date: 2020-11-02T08:41:06Z
• Authors: Vasily Grigorovsky; Daniel Jacobs; Vanessa L Breton; Uilki Tufa; Christopher Lucasius; Jose Martin del C...; Yotin Chinvarun; Peter L Carlen; Richard Wennberg; Berj L Bardakjian
• Keywords: Delta Rhythm

Abstract Postictal generalized EEG suppression is the state of electrical activity at end a seizure. Prolongation this has been associated with increased risk sudden unexpected death in epilepsy, making characterization underlying rhythmic during postictal an important step improving epilepsy treatment. Phase-amplitude coupling reflects cognitive coding within brain networks and some those codes highlight epileptic activity; therefore, we hypothesized that there are distinct phase-amplitude features can provide improved estimate context patient for epilepsy. We used both intracranial scalp data from eleven patients (six male, five female; age range 21–41 years) containing 25 seizures, to identify frequency dynamics, ictal states. Cross-frequency analysis identified seizures was gradual decrease phase between delta (0.5–4 Hz) gamma (30+ Hz), which followed by 0.5–1.5 Hz signal amplitude 30–50 as compared pre-seizure baseline. This marker consistent across patients. Then, using these postictal-specific features, unsupervised classifier—a hidden Markov model—was able reliably classify four states seizure episodes, including state. Furthermore, connectome showed information flow network baseline, suggesting enhanced communication. When same tools were applied who died unexpectedly, dynamics disappeared remained constant throughout. Overall, our findings suggest active networks, defined through be objectively state; furthermore, case study does not show ictal-like despite presence convulsive instead demonstrates similar postictal. The period elevated baseline key insights into pathology.