Gray matter atrophy in patients with Parkinson's disease and those with mild cognitive impairment: a voxel-based morphometry study

Purpose: Mild cognitive impairment is common in Parkinson's disease, but the underlying pathological mechanism has not been fully understood. To examine the gray matter changes in patients with Parkinson's disease and those with mild cognitive impairment (MCI) using voxel based Morphometry (VBM). Methods: Magnetic resonance images were obtained from 35 patients with PD and 20 age and sex-matched healthy control subjects. In the PD group, 14 subjects had no MCI and 21 had MCI. MRI 3D structural images were acquired and analyzed by means of the optimized VBM procedure with Statistical Parametric Mapping (SPM5). Results: Widespread areas of cortical atrophy were found in patients with PD compared with normal controls (in both temporal, occipital, parietal, frontal lobes and right limbic lobes, posterior lobes of the cerebellum and left caudate nucleus). Gray matter reductions were found in bilateral fusiform gyrus and lingual gyrus, left anterior cingulate cortex and insula, and right superior temporal gyrus, orbitofrontal cortex, central gyrus and precuneus in patients with PD with MCI compared with normal controls. Inpatients with PD with MCI, areas of reduced gray matter were found in both precentral gyrus and middle temporal gyrus, right cuneus, precuneus, and orbitofrontal cortex, and left fusiform gyrus compared with those without MCI. Conclusions: These findings suggest that PD is associated with the gray matter atrophy in the neocortical areas, and that cognitive impairment in patients with PD may be associated with gray matter changes in the parieto-occipital association cortex, right orbitofrontal cortex, and middle temporal gyrus.