Frequency-Dependent Dynamics of Functional Connectivity Networks During Seizure Termination in Childhood Absence Epilepsy: A Magnetoencephalography Study.

Jintao Sun,Yulei Sun,Ke Zhang,Yingfan Wang,Jing Xiang,Ailiang Miao,Yihan Li,Xiaoshan Wang

doi:10.3389/fneur.2021.744749

Abstract

Objective: Our aim was to investigate the dynamics of functional connectivity (FC) networks during seizure termination in patients with childhood absence epilepsy (CAE) using magnetoencephalography (MEG) and graph theory (GT) analysis.Methods: MEG data were recorded from 22 drug-naïve patients diagnosed with CAE. FC analysis was performed to evaluate the FC networks in seven frequency bands of the MEG data. GT analysis was used to assess the topological properties of FC networks in different frequency bands.Results: The patterns of FC networks involving the frontal cortex were altered significantly during seizure termination compared with those during the ictal period. Changes in the topological parameters of FC networks were observed in specific frequency bands during seizure termination compared with those in the ictal period. In addition, the connectivity strength at 250–500 Hz during the ictal period was negatively correlated with seizure frequency.Conclusions: FC networks associated with the frontal cortex were involved in the termination of absence seizures. The topological properties of FC networks in different frequency bands could be used as new biomarkers to characterize the dynamics of FC networks related to seizure termination.

Highlights

Childhood absence epilepsy (CAE), with typical electroencephalography (EEG) signals showing 3 Hz spike and wave discharges (SWDs), is one of the most common epilepsy syndromes that occurs in childhood and accounts for 10–17% of epilepsies in children [1, 2]
To minimize the error in the frequency of seizures, we counted the absence seizures observed by parents of children with CAE in the last 1 week to obtain an average of seizure frequency
The duration of the SWDs selected in our analysis is more than 6 s, and there is no overlap between the ictal period and the seizure termination

Summary

Introduction

Childhood absence epilepsy (CAE), with typical electroencephalography (EEG) signals showing 3 Hz spike and wave discharges (SWDs), is one of the most common epilepsy syndromes that occurs in childhood and accounts for 10–17% of epilepsies in children [1, 2]. An increasing number of studies have observed that brain function in children with CAE is persistently impaired [3, 4]. Repeated seizures and epileptic discharges may impair brain function [5]. Epileptic seizures were considered the result of hypersynchronous and abnormal discharges among neurons. Some scholars have reported that hypersynchronized neuronal activity increases the chance of epileptic discharges and eventually leads to epileptic seizures [7,8,9]. It is possible that the decrease in neuronal synchronization could be a necessary process during seizure termination. Inconsistent with the previous assumption, the synchronization of neural activity was reported to increase during seizure termination in several studies [10,11,12]. Understanding the mechanism contributing to seizure termination could offer new insights into its pathophysiological mechanism and be helpful for the development of novel treatments for epilepsy

Methods

Results

Conclusion