Cortical EEG network analysis reveals stage-specific rich-club reorganization across the patients with iRBD and PD

This is the authors' abstract. We don't add key points for this paper.

Idiopathic rapid eye movement sleep behavior disorder (iRBD) has been recognized as a prodromal stage of Parkinson's disease (PD) - a well-known neurodegenerative brain disorder that is characterized by dysconnectivity. Elucidating how brain network topology evolves across the healthy controls (HCs)-iRBD-PD cohorts is crucial for clarifying disease-stage-related neurophysiological alterations. Using EEG source-space connectivity, we aimed to reveal the stage-specific spatio-spectral alterations of rich-club organization (the network's backbone architecture) across these three cohorts. Resting-state high-density EEG data was recorded from 104 participants (HCs/iRBD/PD = 32/33/39). Functional brain networks were estimated via source reconstructed and quantitatively compared across groups. A robust rich-club architecture was identified in all groups, with hubs primarily residing in parietal and temporal areas and exhibiting leftward dominance in the δ, θ, and β bands. Statistical comparisons revealed a significant graded enhancement of rich-club metrics (specifically local connection strength, global efficiency within feeder subnetwork, rich-club-feeder and feeder-local internetworks), predominantly in the θ band, across the three groups. This graded hyperconnectivity likely underscores a disease-stage-dependent reorganization, manifesting as a complex interplay between early compensatory responses and maladaptive pathological synchronization. These findings highlight EEG-based rich-club metrics as potential non-invasive biomarkers for characterizing the PD continuum and provide nascent insights into the neurophysiological mechanisms underlying PD-related disorders.