Brain functional connectivity analysis in patients with relapsing-remitting multiple sclerosis: A graph theory approach of EEG resting state

Abstract

Multiple sclerosis (MS) is an autoimmune disease related to the central nervous system (CNS). This study aims to investigate the effects of MS on the brain's functional connectivity network using the electroencephalogram (EEG) resting-state signals and graph theory approach. Resting-state eyes-closed EEG signals were recorded from 20 patients with relapsing-remitting MS (RRMS) and 18 healthy cases. In this study, the prime objective is to calculate the connectivity between EEG channels to assess the differences in brain functional network global features. The results demonstrated lower cortical activity in the alpha frequency bands and higher activity for the gamma frequency bands in patients with RRMS compared to the healthy group. In this study, graph metric calculations revealed a significant difference in the diameter of the functional brain network based on the directed transfer function (DTF) measure between the two groups, indicating a higher diameter in RRMS cases for the alpha frequency band. A higher diameter for the functional brain network in MS cases can result from anatomical damage. In addition, considerable differences between the networks' global efficiency and transitivity based on the imaginary part of the coherence (iCoh) measure were observed, indicating higher global efficiency and transitivity in the delta, theta, and beta frequency bands for RRMS cases, which can be related to the compensatory functional reaction from the brain. This study indicated that in RRMS cases, some of the global characteristics of the brain's functional network, such as diameter and global efficiency, change and can be illustrated even in the resting-state condition when the brain is not under cognitive load.

Multiple Sclerosis in the Digital Health Age: Challenges and Opportunities - A Systematic Review

“…Similarly, Babiloni et al 55 found that alpha and delta activities in the resting state were lower in PwMS. Conversely, an increase in alpha and gamma was found in 57 . Keune et al showed a correlation between increased alpha 1 and 2 activity, as well as increased frontal theta\beta ratio with worse performance in the symbol digit modalities test (SDMT) test for MS 53 .…”

Multiple Sclerosis in the Digital Health Age: Challenges and Opportunities - A Systematic Review

“…Similarly, Babiloni et al 55 found that alpha and delta activities in the resting state were lower in PwMS. Conversely, an increase in alpha and gamma was found in 57 . Keune et al showed a correlation between increased alpha 1 and 2 activity, as well as increased frontal theta\beta ratio with worse performance in the 3/17 symbol digit modalities test (SDMT) test for MS 53 .…”

“…They revealed an inverse correlation between the P300 amplitude and the fatigue level. Furthermore, evoked potentials in EEG have been analyzed during resting state [51][52][53][54][55][56][57][58][59][60] , during attention tasks [61][62][63][64] or motor tasks 42 . Authors in 11 showed that a combination of evoked potentials (EPs) could predict MS progression in terms of Expanded Disability Status Scale (EDSS) after 20 years.…”