Cortical and subcortical gray matter volume and cognitive impairment in Parkinson's disease

This study investigated the cortical and subcortical gray matter volume (GMV) and cognitive impairment (CI) in patients with Parkinson's disease (PD).

In this study, T1-weighted magnetic resonance imaging of the cortex and subcortex was conducted on 92 individuals diagnosed with PD and 92 healthy controls (HCs). PD patients were divided into three groups: PD with normal cognition (PD-NC, n = 21), PD with mild CI (PD-MCI, n = 43), and PD with severe CI (PD-SCI, n = 28). Differences in GMV were analyzed using voxel-based morphometry (VBM). Statistical analysis was conducted using SPSS 26.

Compared to the HCs, the PD-NC group exhibited reduced GMV in the right middle frontal gyrus (RMFG), right precentral gyrus medial segment (RPGMS), left temporal pole, and right superior frontal gyrus medial segment (RSFGMS). In comparison to the HC and PD-NC groups, the PD-MCI and PD-SCI groups (respectively) demonstrated significant decreases in GMV in the right caudate, left hippocampus, left thalamus, RMFG, RPGMS, RSFGMS, and cerebellum (right crus I and left crus I). The regression analysis indicated that changes in the GMV of the frontal areas can predict cognitive test outcomes.

Compared to HCs, PD patients with CI presented significant volume reductions in the RC, LH, LT, RMFG, RPGMS, RSFGMS, and the right and left crus I regions. Consequently, as average GMV atrophy increased in the specified regions, PD patients exhibited more severe cognitive impairment than the HC group. This may be attributed to the initial pathological loss of frontal GMV (especially in the RMFG and RPGMS regions), which could subsequently lead to subcortical dysfunction.