Chronological Changes in Phase-amplitude Coupling During Epileptic Seizures in Patients with Temporal Lobe Epilepsy
Abstract number :
3.194
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2022
Submission ID :
2204606
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:25 AM
Authors :
Tetsuya Ueda, MD – Juntendo University; Yasushi Iimura, PhD – Juntendo University; Yao Miao, student – Tokyo University of Agriculture and Technology; Takumi Mitsuhashi, PhD – Juntendo University; Hiroharu Suzuki, PhD – Juntendo University; Tamrakar Samantha, Doctor – Juntendo University; Kazuki Nishioka, MD – Juntendo University; Toshihisa Tanaka, Professor – Tokyo University of Agriculture and Technology; Hidenori Sugano, PhD – Juntendo University
Rationale: Phase-amplitude coupling (PAC) analysis of interictal epileptic discharges has been investigated for epileptic focal diagnosis. In this study, we analyzed chronological changes in PAC during epileptic seizures and verified that PAC analysis can diagnose epileptogenic zone even during seizures.
Methods: We analyzed 30 seizures with mesial temporal lobe epilepsy who had a class 1 outcome according to Engel’s classification. The epileptogenic zone was the hippocampus in all patients according to common diagnostic methods and surgical results. We selected ictal discharge with preictal spiking followed by low-voltage fast activity pattern from our intracranial electroencephalography (EEG) database. The modulation index (MI) was used as an indicator of PAC in this study. We used the amplitude of two high-frequency bands (ripples: 80-200 Hz, fast ripples: 200-300 Hz) and the phase of three slow wave bands (0.5-1 Hz, 3-4 Hz, and 4-8 Hz) for MI calculation. MIs were calculated continuously from 2 minutes before seizure onset to seizure termination. The epochs of interictal and ictal phases were 100 each. We evaluated the accuracy of epileptogenic zone detection by MI, in which a combination of MI was better for diagnosis, and also analyzed the patterns of chronological changes in MI during seizures.
Results: The MIRipples/3-4 Hz and MIRipples/4-8 Hz in the hippocampus were significantly higher than those in the peripheral regions from seizure onset. The MIRipples/3-4 Hz decreased once, corresponding to low-voltage fast activity, and subsequently increased again from the evolution phase on intracranial EEG. The MIRipples/4-8 Hz showed continuously high values.
Conclusions: The continuous measurement of MIs, especially MIRipples/3-4 Hz and MIRipples/4-8 Hz, could provide information for predicting the epileptogenic zone. Ictal PAC analysis showed a significant increase from seizure onset, and this method could be used as an EEG feature for seizure prediction.
Funding: None
Neurophysiology