Structural Volumetric Alterations in Parkinson's Disease With Mild Cognitive Impairment

BACKGROUND: Parkinson's disease with mild cognitive impairment (PD-MCI) is a critical dementia prodrome, but its structural neuropathology remains incompletely defined. While hippocampal atrophy is established, volumetric changes in other subcortical structures are poorly characterized. OBJECTIVE: To perform the first comprehensive meta-analysis quantifying gray matter volume alterations across six subcortical regions in PD-MCI. METHODS: ), publication bias, sensitivity analyses, and meta-regression were assessed. RESULTS: ). Bilateral caudate nuclei volumes were preserved. Sensitivity analyses confirmed robustness. Meta-regression identified segmentation tools and country as sources of left hippocampal heterogeneity (p < 0.05). No publication bias was detected. CONCLUSION: PD-MCI exhibits a distinct subcortical atrophy signature involving limbic-striato-thalamic networks, with right globus pallidus atrophy as a novel lateralized biomarker. Network-based imaging paradigms are advocated, requiring standardized protocols and longitudinal validation. SYSTEMATIC REVIEW REGISTRATION: Identifier PROSPERO (CRD420251051275).