The pattern of cortical atrophy in patients with Parkinson's disease according to cognitive status

Abstract

Cognitive dysfunction is common in Parkinson's disease (PD), and along with PD with dementia (PDD), the concept of mild cognitive impairment in PD (PD-MCI) has been introduced. To identify structural candidates according to cognitive status in PD, we compared gray matter (GM) density across PD-intact cognition (PD-IC, n = 23), PD-MCI (n = 27), and PDD (n = 18) using voxel-based morphometry. The demographic data among PD subjects were similar, however, general cognition and disease duration were more severe in PD-MCI and PDD than in PD-IC. Compared with controls, GM density was significantly decreased in the left occipital area in PD-IC; the bilateral temporal, left prefrontal and insular, and right occipital areas in PD-MCI; and in widespread brain areas in PDD. Compared with PD-IC, patients with PD-MCI had significantly decreased GM density in the right middle frontal area, and those with PDD had decreased GM density in the right parietal, middle frontal, insular, and lentiform areas. GM density in patients with PDD was significantly decreased in the bilateral middle temporal, right inferior temporal, and left middle and superior prefrontal areas. PDD patients with shorter disease duration before dementia (<5 year) showed greater GM atrophy in the posterior cingulate area than did those with longer disease duration (≥5 year). These data suggest that cortical atrophy in PD exhibits a greater extent with increasing levels of cognitive impairment, and different anatomical substrates would correspond to each cognitive status.