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The following is a summary of “Association of Early fMRI Connectivity Alterations With Different Cognitive Phenotypes in Patients With Newly Diagnosed Parkinson Disease,” published in the December 2024 issue of Neurology by Bartolo et al.
People with Parkinson’s disease (PD) and visuospatial deficits are more likely to progress to dementia compared with those who experience predominantly dysexecutive symptoms, according to the dual syndrome hypothesis.
Researchers conducted a prospective study investigating whether early functional connectivity changes in the dorsolateral prefrontal cortex (DLPFC) and the precuneus (PCun) can differentiate cognitive phenotypes in people with newly diagnosed PD.
They enrolled individuals with newly diagnosed, drug-naïve PD (≤2 years from clinical onset) and normal Montreal Cognitive Assessment (MoCA) scores, along with age-matched and sex-matched HCs. Participants underwent 3T-functional magnetic resonance imaging (3T-fMRI) to assess resting-state functional connectivity (rs-FC) in the DLPFC and PCun, K-means cluster analysis grouped participants with PD based on connectivity patterns. Differences in neurophysiologic, motor, and nonmotor outcomes were evaluated at baseline (T0) and at 3.5 years of follow-up (T1), with significance set at P<.05.
The results showed 68 people with PD (27% women; mean age 60 ± 9 years; Hoehn and Yahr score 1.4 ± 0.5; MoCA score 27.9 ± 1.6) demonstrated reduced rs-FC in the DLPFC and PCun compared with 31 HCs (39% women; mean age 64.2 ± 9.3 years). Cluster 1, defined by the lowest connectivity values, had worse performance in global cognition, fronto-executive, and memory domains at T0 compared with clusters 2 and 3 (P<.031). At T1, clusters 1 and 3 showed declines in global cognition, visuospatial and fronto-executive function, motor symptoms, and nonmotor symptoms, with a higher prevalence of mild cognitive impairment (MCI) compared with cluster 2 (P<.04).
They concluded that early changes in functional connectivity in the DLPFC and PCun can identify distinct cognitive phenotypes in people with newly diagnosed PD and predict the clinical progression.
Source: neurology.org/doi/10.1212/WNL.0000000000210192
