White Matter Microstructural Damage and Cognitive Impairment in Parkinson’s Disease (S40.005)

OBJECTIVE: The aim of this study was to investigate white matter microstructural damage and its relationship with cognitive impairment in a large population of patients with Parkinson’s disease (PD) at different disease stages. BACKGROUND: Cognitive deficits are common in PD and can occur even in the early stages of the disease. Cognitive deficits in PD usually involve executive functions and can result in a mild cognitive impairment (MCI) evolving to overt dementia. DESIGN/METHODS: We enrolled 168 PD patients (105 without cognitive impairment [PD-ncog]; 48 with MCI [PD-MCI] and 15 with dementia [PD-DEM]), and 41 healthy controls (HC). PD and controls underwent a clinical and neuropsychological evaluation. Tract-based spatial statistics were used to perform a voxel-wise analysis of fractional anisotropy (FA) and mean diffusivity (MD), adjusted for subject’s age. RESULTS: All PD patients showed decreased FA and increased MD in the splenium of corpus callosum (CC), right frontal WM and internal capsule. In PD-MCI, WM damage spreads to anterior regions of CC, bilateral frontal, anterior temporal and parietal WM. WM damage increased in severity in PD-DEM, involving frontal and parietal WM . PD-DEM vs PD-ncog patients showed alterations in the body of CC There were no differences in DT MRI metrics in PD-DEM vs PD-MCI subjects. CONCLUSIONS: WM damage in PD becomes more severe with worsening of cognitive performance. WM damage spreads in the anterior regions in PD-MCI, showing the maximum severity in PD-DEM patients. Assessing WM alterations may improve the understanding of the mechanisms associated with cognitive impairment in PD. Study Supported by: Italian Ministry of Health (#GR-2009-1577482); Ministry of Science and Technology of the Republic of Serbia (#175095).