Postictal generalized EEG suppression is the state of suppression of electrical activity at the end of a seizure. Prolongation of this state has been associated with increased risk of sudden unexpected death in epilepsy, making characterization of underlying electrical rhythmic activity during postictal suppression an important step in improving epilepsy treatment. Phase-amplitude coupling in EEG reflects cognitive coding within brain networks and some of those codes highlight epileptic activity; therefore, we hypothesized that there are distinct phase-amplitude coupling features in the postictal suppression state that can provide an improved estimate of this state in the context of patient risk for sudden unexpected death in epilepsy. We used both intracranial and scalp EEG data from eleven patients (six male, five female; age range 21-41 years) containing 25 seizures, to identify frequency dynamics, both in the ictal and postictal EEG suppression states. Cross-frequency coupling analysis identified that during seizures there was a gradual decrease of phase frequency in the coupling between delta (0.5-4 Hz) and gamma (30+ Hz), which was followed by an increased coupling between the phase of 0.5-1.5 Hz signal and amplitude of 30-50 Hz signal in the postictal state as compared to the pre-seizure baseline. This marker was consistent across patients. Then, using these postictal-specific features, an unsupervised state classifier-a hidden Markov model-was able to reliably classify four distinct states of seizure episodes, including a postictal suppression state. Furthermore, a connectome analysis of the postictal suppression states showed increased information flow within the network during postictal suppression states as compared to the pre-seizure baseline, suggesting enhanced network communication. When the same tools were applied to the EEG of an epilepsy patient who died unexpectedly, ictal coupling dynamics disappeared and postictal phase-amplitude coupling remained constant throughout. Overall, our findings suggest that there are active postictal networks, as defined through coupling dynamics that can be used to objectively classify the postictal suppression state; furthermore, in a case study of sudden unexpected death in epilepsy, the network does not show ictal-like phase-amplitude coupling features despite the presence of convulsive seizures, and instead demonstrates activity similar to postictal. The postictal suppression state is a period of elevated network activity as compared to the baseline activity which can provide key insights into the epileptic pathology.
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http://dx.doi.org/10.1093/braincomms/fcaa182 | DOI Listing |
World J Psychiatry
December 2024
Department of Digital Anti-aging Healthcare (BK21), Inje University, Gimhae 50834, South Korea.
This editorial evaluated the findings of a comprehensive study focused on the effects of anesthesia depth on seizure parameters during electroconvulsive therapy (ECT) in patients with major depressive disorder. The study utilized quantitative consciousness and quantitative nociceptive indices for monitoring sedation, hypnosis, and nociceptive responses. The analysis included 193 ECT sessions across 24 patients, revealing significant impacts of anesthesia depth on electroencephalography (EEG) seizure parameters.
View Article and Find Full Text PDFEncephale
November 2024
University of Tunis El Manar, Faculty of Medicine of Tunis, Department of Psychiatry D, Razi Hospital, Manouba, Tunisia.
Epilepsy Behav
December 2024
Neurology, Epilepsy and Movement Disorders Unit, Bambino Gesù, IRCCS Children's Hospital, Full Member of European Reference Network EpiCARE, Rome, Italy.
Objective: We studied the electrographic features of tonic seizures (TS) with bilateral contraction and tonic-clonic seizures (TCS) without focal signs occurring during the first year of life to evaluate if there is a correlation with outcome.
Methods: We retrospectively reviewed patients aged 1 to 12 months with at least one TS or TCS recorded with video-EEG between 2011 and 2021 in our Epilepsy Monitoring Unit. We analyzed the following electrographic features: seizure duration, presence and duration of focal ictal EEG onset, and post-ictal generalized EEG suppression (PGES).
Elife
October 2024
Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, United States.
Neurogenesis occurs in the adult brain in the hippocampal dentate gyrus, an area that contains neurons which are vulnerable to insults and injury, such as severe seizures. Previous studies showed that increasing adult neurogenesis reduced neuronal damage after these seizures. Because the damage typically is followed by chronic life-long seizures (epilepsy), we asked if increasing adult-born neurons would prevent epilepsy.
View Article and Find Full Text PDFBMC Psychiatry
October 2024
Department of Medical Sciences, Uppsala University, Entrance 10, Uppsala, 751 85, Sweden.
Background: Electroconvulsive therapy (ECT) is an important treatment for several severe psychiatric conditions, yet its precise mechanism of action remains unknown. Increased inhibition in the brain after ECT seizures, mediated by γ-aminobutyric acid (GABA), has been linked to clinical effectiveness. Case series on epileptic patients report a postictal serum concentration increase of the GABA receptor agonist allopregnanolone.
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