152 patients with PD underwent clinical assessment, cognitive evaluation and MRI scan on a 1.5 Tesla scanner (including T2-weighted and diffusion tensor [DT] MRI sequences) once a year over a follow-up time of 36 months. White matter lesions (WML) were manually identified on T2-weighted scans and the total WML volume was calculated for each subject. Applying tract-based spatial statistics (TBSS), mean fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (axD) and radial diffusivity (radD) values of the total WM skeleton were extracted. Longitudinal regression models and Pearson correlation analyses between MRI and clinical/cognitive data were performed, adjusting for baseline motor impairment measured using the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III).

Longitudinal evolution of WM microstructural damage is associated with both motor and global cognitive deterioration in PD, and DT MRI might provide a sensitive biomarker of disease progression. The observed increase over time of WM macroscopic alterations is probably not related with neurodegenerative mechanisms.