Objective: Aim of the present study was to characterize the dynamic changes of functional connectivity associated with Parkinson’s disease (PD) cognitive decline using dynamic functional connectivity (DFC) approach.

Background: DFC helps capture temporal variations of functional connectivity during magnetic resonance imaging acquisition and it may be a suitable method to capture changes related to cognitive deficits in PD.

Method: One-hundred eighteen PD patients were matched for age, sex and education with 35 healthy controls (HC), and classified as 52 PD with normal cognition (PD-NC), 46 with mild cognitive impairment (PD-MCI), and 20 with dementia (PDD) based on an extensive cognitive evaluation. Resting-state scans were acquired on 1.5T scanner in two consecutive scanning runs of approximately eight minutes each. A sliding window approach was used to study the DFC. We investigated the temporal properties of DFC states by computing the average dwell time and fractional windows in each state, as well as the number of transitions from one state to another.

Results: Dynamic analysis suggested two distinct connectivity states across the entire group: a more frequent, segregate brain state characterized by the predominance of within-network connections, State I, and a less frequent, integrated state with strongly connected functional inter-network components, State II. In PD, the occurrence of State I occurred 13.89% more often than in HC, paralleled by a proportional reduction of State II. Subgroups analyses showed the segregated state occurred more frequently in PDD than in PD-MCI and PD-NC. Further, PDD dwelled significantly longer in the segregated State I, and showed a significant lower number of transitions to the strongly interconnected State II compared to the other groups.

Conclusion: Our study indicates cognitive decline in PD is characterized by altered temporal properties in dynamic connectivity, suggesting reduced ‘crosstalk’ between brain networks and increased segregation. To finalize, our findings provide novel insight into dynamic functional changes of cognitive deficits in PD, which can possibly reflect PD cognitive states and serve as a prognostic biomarker of cognitive decline.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dynamic-functional-connectivity-signature-of-cognitive-decline-in-parkinsons-disease/