Cognitive profiles and brain alterations in prodromal and Parkinson's disease individuals

We aimed to characterize cognitive profiles and brain morphology correlates of Prodromal and Parkinson's disease (PD) patients from the Parkinson's Progression Markers Initiative program, given the value of detecting Mild Cognitive Impairment (MCI) as a risk factor for dementia in the Prodromal stage. K-means clustering analysis was performed to identify distinct cognitive profiles based on the cognitive domain scores of the Montreal Cognitive Assessment, while volumetric quantification of brain regions was conducted using the AssemblyNet pipeline on T13D MRI brain images. Distinct cognitive profiles were identified in the PD and Prodromal cohorts: Cognitively intact (CI), Mildly affected (MI) and Mostly affected (MO). In the PD cohort, we observed decreased left cerebellar volume in MI subjects and decreased total cerebellar white matter volume in the MO when compared with CI subjects. In the Prodromal cohort, the MO group showed decreased total brain volume compared to the CI group. Cerebral and cerebellar white matter volumes were also significantly reduced, whereas lateral ventricular volume was increased. Altered structures in the MO group of Prodromal participants were compared with a Control cohort without MCI and also showed volume reduction. Cognitively affected participants of the PD cohort showed no cerebellar volume differences compared with the Control cohort. Similar cognitive profiles observed in both Prodromal and PD cohorts suggest the presence of comparable cognitive deficits in these individuals, being the PD patients and the episodic memory domain the most affected. Prodromal individuals exhibited greater morphological differences, suggesting brain alterations in the absence of PD symptoms.