Dynamic Functional Network Connectivity Analysis in Autism Spectrum Disorder: An EEG Study

Convergent evidence has suggested a significant effect of bumetanide exposure on brain connectivity in patients with autism spectrum disorder (ASD), yet the characteristics of favorable treatment outcome remains largely unknown. In this work, we aimed to elucidate the primary group distinctions in the temporal pattern of dynamic functional connectivity (dFC) estimated from task based EEG among individuals with ASD and healthy controls (HC) and explore the effect of bumetanide on brain network states. Through a systematic analysis, we investigated the ASD-related intrinsic alterations of dFC at baseline, followed by a longitudinal study to examine the influence of bumetanide treatment on these abnormalities by comparing patients at baseline and follow-up. EEG data was recorded from 9 individuals with ASD and 9 HC at baseline. After 3 months of bumetanide treatment, EEG data was re-recorded from the individuals with ASD. Utilizing phase locking value, sliding-window analysis, and K-means clustering, we obtained dFC for the alpha, beta, and gamma bands, and observed three repeating brain states. Two temporal metrics of connectivity state expression including fraction of time (FT) and dwell time (DT) were calculated. The results showed that in the alpha and gamma bands, FT and DT in ASD groups before bumetanide treatment were higher in the strong connection state and lower in the weak connection state compared to the HC group. Also, the use of bumetanide led to a significant decrease in the difference between the HC and ASD groups, although the adjustment made in the gamma band was more significant.