Disrupted functional connectivity in PD with probable RBD and its cognitive correlates

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Rapid eye movement sleep behavior disorder (RBD) is linked to severe cognitive impairment and brain atrophy in Parkinson's disease (PD).
• Whole-brain functional connectivity in PD patients with probable RBD (PD-pRBD) remains underexplored.

Purpose of the Study:

• To investigate whole-brain functional connectivity using network-based statistics and graph theory in PD-pRBD patients.
• To explore the relationship between functional connectivity and cognitive performance in PD-pRBD.

Main Methods:

• Compared resting-state functional connectivity in 32 PD without probable RBD (PD-non pRBD), 27 PD-pRBD, and 30 healthy controls.
• Utilized network-based statistics and graph-theoretical analyses to assess interregional functional connectivity.

Main Results:

• PD-pRBD patients exhibited reduced functional connectivity compared to controls, particularly in cingulate, temporal, frontal, insular, and thalamic regions.
• PD-pRBD showed decreased connectivity between the right ventral posterior cingulate and left medial precuneus versus PD-non pRBD.
• Increased normalized characteristic path length was observed in PD-pRBD compared to PD-non pRBD.

Conclusions:

• PD-pRBD demonstrates significantly disrupted functional connectivity and altered network integrity.
• These findings support classifying PD-pRBD as a distinct and more severe subtype of Parkinson's disease.
• Connectivity alterations correlate with specific cognitive deficits, including visuoperception, processing speed, and verbal memory.