Cognitive impairment in Parkinson's disease is associated with Default Mode Network subsystem connectivity and cerebrospinal fluid Aß. Parkinsonism & related disorders Zarifkar, P. n., Kim, J. n., La, C. n., Zhang, K. n., YorkWilliams, S. n., Levine, T. F., Tian, L. n., Borghammer, P. n., Poston, K. L. 2021; 83: 71–78


To identify clinically implementable biomarkers of cognitive impairment in Parkinson's Disease (PD) derived from resting state-functional MRI (rs-fMRI) and CSF protein analysis.In this single-center longitudinal cohort study, we analyzed rs-fMRI and CSF biomarkers from 50 PD patients (23 cognitively normal, 18 mild cognitive impairment, 9 dementia) and 19 controls, who completed comprehensive neuropsychological testing. A subgroup of participants returned for follow-up cognitive assessments three years later. From rs-fMRI, we studied the connectivity within two distinct Default Mode Network subsystems: left-to-right hippocampus (LHC-RHC) and medial prefrontal cortex-to-posterior cingulate cortex (mPFC-PCC). We used regression analyses to determine whether imaging (LHC-RHC, mPFC-PCC), clinical (CSF Aß-42:40, disease duration), and demographic (age, sex, education) variables were associated with global and domain-specific cognitive impairments.LHC-RHC (F3,67 = 3.41,p=0.023) and CSF Aß-42:40 (?2(3) = 8.77,p = 0.033) were reduced across more cognitively impaired PD groups. Notably, LHC-RHC connectivity was significantly associated with all global and domain-specific cognitive impairments (attention/executive, episodic memory, visuospatial, and language) at the baseline visit. In an exploratory longitudinal analysis, mPFC-PCC was associated with future global and episodic memory impairment.We used biomarker techniques that are readily available in clinical and research facilities to shed light on the pathophysiologic basis of cognitive impairment in PD. Our findings suggest that there is a functionally distinct role of the hippocampal subsystem within the DMN resting state network, and that intrinsic connectivity between the hippocampi is critically related to a broad range of cognitive functions in PD.

View details for DOI 10.1016/j.parkreldis.2021.01.002

View details for PubMedID 33484978