Electroencephalographic-Based Functional Connectivity Networks of Visual Hallucinations and Visuospatial Dysfunctions in Parkinson's Disease.

Visual dysfunction is an important nonmotor symptom of Parkinson's disease (PD). Visual hallucinations (VHs) and visuospatial dysfunctions (VSDs) are common visual dysfunctions in PD; however, the underlying mechanisms remain unclear. Our study aimed to evaluate neuronal synchronization between patients with PD with and without VH or VSD using electroencephalographic (EEG) coherence analysis. Twenty-four patients with sporadic PD were evaluated for the presence of VH and VSD, and were divided into VH-negative and VH-positive groups, and these groups were further subdivided by VSD status. Coherence analysis was performed on EEG data. Whole-brain and regional coherences were calculated and compared between the groups. There was a significant difference in frontal-frontal coherence between the VH+ VSD- and VH+ VSD+ groups (p = 0.026). Our findings suggest that reduced EEG coherence in frontal regions might be involved in VSD in patients with PD. Reduced neuronal synchronization between the frontal lobes may contribute to the disruption of visual processing in PD.