Choroid plexus enlargement as an imaging correlate of cognitive impairment in Parkinson’s disease: a normative brain-charts analysis

Cognitive impairment profoundly affects the quality of life in patients with Parkinson’s disease (PD), yet reliable early biomarkers remain lacking. This study enrolled 234 PD patients, who were stratified into cognitive impairment (PD-CI, n = 147) and normal cognition (PD-NC, n = 87) groups based on Montreal Cognitive Assessment scores. Brain MRI volumetric data were processed using FreeSurfer, and brain charts—applied to Parkinson’s disease for the first time—were computed to quantify deviation from normative brain aging trajectories. Compared with PD-NC patients, those with PD-CI exhibited significantly increased normalized choroid plexus volume (CPV/TIV), reduced brain chart scores, and lower serum albumin levels. After adjustment for age, sex, education, disease duration, UPDRS-III, and Hoehn-Yahr stage, the choroid plexus principal component remained the only imaging component independently associated with PD-CI (OR = 4.99, 95% CI 2.39–10.41, P < 0.001), whereas the brain regional volume component was independently protective. In internally validated models (repeated cross-validation with bootstrap optimism correction), adding the choroid plexus component improved discrimination of PD-CI (optimism-corrected AUC 0.845, 95% CI 0.829–0.916), whereas the normative brain-charts index provided no additional discriminative value. These findings identify choroid plexus enlargement as a promising imaging correlate and candidate predictor of cognitive impairment in PD; the association is consistent with, but does not by itself establish, a contribution of glymphatic dysfunction, and may inform future work on early detection and intervention.