2023 American Academy of Neurology Abstract Website

Laura Mora-Munoz ¹, Noah Andrews¹, Matheus Araujo¹, Loutfi Aboussouan¹, William Bingaman ², Lu Wang ³, Madeleine Grigg-Damberger⁴, Nancy Foldvary Schaefer¹
¹Department of Neurology, Sleep Disorders and Epilepsy Centers, Cleveland Clinic Neurological Institute, Cleveland, OH, ²Department of Neurological Surgery, Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland Clinic Foundation, ³Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH, Cleveland Clinic Foundation, Lerner Research Institute, ⁴Department of Neurology, University of New Mexico, Albuquerque, NM, University of New Mexico

Objective:

To identify peri-ictal respiratory disturbances associated with postictal generalized EEG suppression (PGES) and sleep.

Background:

Seizure-related respiratory dysfunction may predispose to sudden unexpected death in epilepsy (SUDEP), yet existing studies are based largely on scalp recordings and lack comprehensive polysomnographic (PSG) signals. PGES (absence of EEG activity >10μV) is a proposed biomarker of SUDEP and most cases of SUDEP occur during sleep.

Design/Methods:

We studied respiratory changes in stereoelectroencephalography (SEEG)-recorded perisylvian seizures using a multimodal system integrating EEG and PSG signals including airflow, effort, SpO₂, and CO₂. Sleep state and PGES were defined by scalp electrodes (FZ/CZ). Interpretable recordings required SpO₂ and at least one airflow and effort channel. Respiratory events were scored during focal and generalized phases. Frequency and duration of events were compared by state and PGES status using two-sample t-test or Kruskal-Wallis test based on 0.05 significance level using SAS 9.4 software.

Results:

61 seizures (29 patients) were included. Compared to seizures without PGES, PGES seizures (N=8) were associated with higher central event frequency (median [IQR]: 3.0[3.0,4.0] vs 1.0[1.0,1.0], P<0.001) and duration (76[63,94] vs 27[12.5,35] sec, P=0.010); higher ictal RR (mean±SD: 28.5±1.5 vs 24.6±4.6 bpm, P<0.001), pre-ictal-to-ictal RR change (8.1±3.2 vs 2.3±3.2 bpm, P<0.001) and pre-ictal-to-peak TcpCO₂change (16.4 [11.6,31.0] vs 2.2 [0.45,7.2] mmHg, P=0.023); and greater pre-ictal-to-nadir SPO₂ change (24.0 [23.0,24.4] vs 4.1 [2.4,11.0] %, P=0.033). However, PGES was not associated with sleep state. In contrast, sleep seizures (N=35) were differentiated from wake seizures only by lower pre-ictal (19.9±2.5 vs 24.1±3.1 bpm, P<0.001), ictal (22.6±4.3 vs 28.0±2.7 bpm, P<0.001), and postictal RR (24.7±5.22 vs 8.5±4.4 bpm, P=0.020), and higher pre-ictal TcpCO₂ (40.6[38.1, 42.6] vs 36.8[32.8, 39.5] mmHg, P=0.006).

Conclusions:

PGES (and not sleep) in perisylvian seizures is associated with a host of respiratory disturbances, providing further support of its role as a biomarker of SUDEP.