J Clin Neurol.  2019 Apr;15(2):211-220. 10.3988/jcn.2019.15.2.211.

Electroencephalographic Resting-State Functional Connectivity of Benign Epilepsy with Centrotemporal Spikes

• Choi HS
• Chung YG
• Choi SA
• Ahn S
• Kim H
• Yoon S
• Hwang H
• Kim KJ

• KMID: 2467735
• DOI: http://doi.org/10.3988/jcn.2019.15.2.211

Abstract

BACKGROUND AND PURPOSE
We aimed to reveal resting-state functional connectivity characteristics based on the spike-free waking electroencephalogram (EEG) of benign epilepsy with centrotemporal spikes (BECTS) patients, which usually appears normal in routine visual inspection.
METHODS
Thirty BECTS patients and 30 disease-free and age- and sex-matched controls were included. Eight-second EEG epochs without artifacts were sampled and then bandpass filtered into the delta, theta, lower alpha, upper alpha, and beta bands to construct the association matrix. The weighted phase lag index (wPLI) was used as an association measure for EEG signals. The band-specific connectivity, which was represented as a matrix of wPLI values of all edges, was compared for analyzing the connectivity itself. The global wPLI, characteristic path length (CPL), and mean clustering coefficient were compared.
RESULTS
The resting-state functional connectivity itself and the network topology differed in the BECTS patients. For the lower-alpha-band and beta-band connectivity, edges that showed significant differences had consistently lower wPLI values compared to the disease-free controls. The global wPLI value was significantly lower for BECTS patients than for the controls in lower-alpha-band connectivity (mean±SD; 0.241±0.034 vs. 0.276±0.054, p=0.024), while the CPL was significantly longer for BECTS in the same frequency band (mean±SD; 4.379±0.574 vs. 3.904±0.695, p=0.04). The resting-state functional connectivity of BECTS showed decreased connectivity, integration, and efficiency compared to controls.
CONCLUSIONS
The connectivity differed significantly between BECTS patients and disease-free controls. In BECTS, global connectivity was significantly decreased and the resting-state functional connectivity showed lower efficiency in the lower alpha band.

Keyword

functional connectivity; electroencephalography; resting state; epilepsy; benign epilepsy with centrotemporal spikes

MeSH Terms

Artifacts
Electroencephalography
Epilepsy
Epilepsy, Rolandic*
Humans

Figure

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  Fig. 1 Power spectral density graphs. Absolute (A) and relative (B) PSD graphs for the benign epilepsy with centrotemporal spikes and control groups, with bars showing median and median absolute deviation values. The results were similar for the PSD, and activity peaked in the lower alpha band. PSD: power spectral density.

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  Fig. 2 A heat map of an adjacent matrix plot of band-specific resting-state functional connectivity (A) and differences of the edges (B). The heat map shows the connectivity in the delta, theta, lower alpha, upper alpha, and beta bands with different color scales for each band. The p values were not corrected for each frequency band or the 171 edges. Only a certain band and an edge were compared between benign epilepsy with centrotemporal spikes patients and controls to produce the connectivity difference pattern.

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  Fig. 3 Graph presentation of edges showing significant differences in a specific band and an edge between benign epilepsy with centrotemporal spikes patients and controls (p-value correction was not performed).

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  Fig. 4 Comparison of the lower-alpha-band connectivity itself between benign epilepsy with centrotemporal spikes patients and controls using two-sided t-tests without correction (A) and with one-sided (patient

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  Fig. 5 Mean global wPLI values (A) and CPL of benign epilepsy with centrotemporal spikes patients and controls, with error bars indicating standard deviations. CPL: characteristic path length, wPLI: weighted phase lag index.

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