Brain functional connectivity in Parkinson’s disease – EEG resting analysis

Abstract

Brain functional connectivity evaluates the statistical dependencies between spatially distributed brain regions. The patterns obtained from this analysis have been related to different cognitive processes and are altered by neurodegenerative diseases. Parkinson’s disease (PD) is the second most frequent neurodegenerative disease and presents a combination of motor and cognitive disturbances. In this study the early changes in connectivity patterns in PD are evaluated. EEG was recorded at resting state with eyes closed in twenty-three patients with PD without cognitive decline (PD-CogNL) and twenty three healthy controls. Spectral coherence was estimated between electrode pairs in fronto-parietal and inter-hemispheric regions. Rhythms of interest were: delta (1–4 Hz), theta (4–8 Hz), alpha1 (8–10 Hz), alpha2 (10–13 Hz), beta1 (13–20 Hz), and beta2 (20–30 Hz). Compared to controls, PD-CogNL had an increased coherence in frontal inter-hemispheric electrodes in delta and theta bands. In the fastest bands were found correlations between connectivity and executive function measured by INECO test. The results of this paper show early changes in frontal inter-hemispheric coupling in PD.