Different Signatures of Loss of Consciousness During Focal Seizures and Natural Sleep
Abstract number :
2.131
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2024
Submission ID :
1135
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Urszula Gorska-Klimowska, PhD – University of Wisconsin-Madison
Maximilian Grobbelaar, BS – EPFL
Csaba Kozma, BSc – Newcastle University
Cole Cimoch, BS – University of Wisconsin-Madison
Jackson Haskins, BS – University of Wisconsin-Madison
Cynthia Papantonatos, BS – University of Wisconsin-Madison
Marek Solvik, BS – University of Wisconsin-Madison
Dillon Scott, BS – University of Wisconsin
Brinda Sevak, BS – UC Davis
Elena Monai, MD – University of Wisconsin-Madison
Mariel Kalkach Aparicio, MD, MBE – University of Wisconsin-Madison
Cameron Brace, BS – University of Wisconsin-Madison
Elsa Juan, PhD – University of Wisconsin-Madison
Aaron Struck, MD – University of Wisconsin-Madison
Giulio Tononi, Prof. – University of Wisconsin-Madison
Melanie Boly, MD PhD – University of Wisconsin-Madison
Rationale: Loss of consciousness (LOC) occurring during epileptic seizures can cause life-threatening repercussions for the patients. Recent studies have associated LOC during sleep with increased slow wave activity (SWA) in the brain, and interestingly thalamo-cortical sleep-like activities were also lately identified for focal impaired awareness (FIA) seizures. However, the similarities and differences between SWA during physiological non-rapid eye movement (NREM) sleep and FIA seizures remain poorly understood. Moreover, the presence of this activity was not yet explicitly studies for focal aware (FA) seizures.
Methods: In this study, we analyzed intracranial EEG (iEEG) recordings of 18 periods of light and deep sleep, 23 FA and 34 FIA seizures, obtained from 18 epileptic patients. We computed the evolution of beta/ delta ratio, which has been shown to differentiate sleep from wakefulness better than SWA (Kremen et al., 2019; Reed et al., 2017), over the course of the night. We classified deep sleep as a prominent peak at the beginning at light sleep as a slight increase at the end of the night. We quantified clinical signs of LOC based on video-EEG review and scoring of both behavioral responsiveness and/or amnesia of seizures to differentiate FIA seizures. We compared delta power (1 – 4 Hz, SWA) in various brain regions.
Results: We found similarities in SWA increases in FIA seizures and deep sleep in the temporo-parieto-occipital (with 2-fold increase) and in the parietal somatosensory (1-fold) areas, but we observed differences, with a stronger increase during deep sleep than during FIA seizures in the motor and premotor (p >0.01), and the dorsolateral prefrontal (dlPFC) and the orbitofrontal (OBF; p >0.001) areas. Additionally, we found similarities in SWA increases between FIA seizures and light sleep in motor and premotor (1-fold) and in the dlPFC (1.5-fold) areas. We also detected increases in SWA for FA seizures in the temporo-parieto-occipital area which was stronger than during sleep (p< 0.001), and in OBF (although less pronounced than during sleep, p< 0.001), but not in any other area.
Neurophysiology