Authors :
Presenting Author: Woojun Kim, MD, PhD – The Catholic University of Korea
Jean Hee Kim, MD – The Catholic University of Korea; Seong Hoon Kim, MD, PhD – The Catholic University of Korea
Rationale:
Patients with epilepsy frequently experience autonomic dysfunction which is closely related to sudden unexplained death in epilepsy (SUDEP). SUDEP occurs most often at night or during sleep, and frequent nocturnal seizures are its known risk factor. This study investigated the influence of nocturnal seizures on autonomic dysfunction in epilepsy.
Methods:
This retrospective study enrolled frontal lobe epilepsy (FLE) patients confirmed after 24-hr EEG monitoring. All participants were divided into diurnal FLE (DFLE) or nocturnal FLE (NFLE) groups. The NFLE was defined as more than 90% of seizures occurring during sleep and the remaining participants were classified as the DFLE. During the 24-hr EEG monitoring, EEG and ECG signals were simultaneously obtained during each participant's waking and sleep stages. EEG current density source and connectivity analysis of the autonomic network were performed. ECG was analyzed by time and frequency domain and using non-linear heart rate variability (HRV) analysis method. The obtained EEG and HRV parameters were compared between the NFLE and DFLE groups.
Results:
Fifteen NFLE (12 males; median age, 23; range, 14-54 years) and 16 DFLE (9 males; median age, 30; range, 15-65 years) patients were enrolled. There was no significant difference in age, sex, disease duration, seizure frequency, and the number of antiepileptic drugs between the two groups. During the sleep stage, a decrease in HRV parameters and an increase of the beta-1 (13-22 Hz) current source density power (p< 0.05) in the bilateral paracentral lobule (BA4,5,6) precuneus (BA7), and cingulate (BA31) were observed in the NFLE group. The NFLE group also showed hyperconnectivity in the central autonomic (p< 0.05, t=4.0971, 12 edges distributed over 10 nodes), sympathetic (p< 0.05, t=3.9691, 2 edges distributed over 3 nodes), and parasympathetic (p< 0.05, t=4.0282, 4 edges distributed over 6 nodes) networks of the beta-1 frequency band during sleep. Analysis of HRV and EEG did not show significant differences during the waking stage.