Visual rating of white matter hyperintensities in Parkinson's disease.

Dementia is a common complication of Parkinson's disease (PD), but the cause is incompletely understood. In previous studies, dementia has been associated with an increase in hyperintense lesions in the cerebral white matter. The aim of this study was to explore whether white matter hyperintensities (WMH) on cerebral magnetic resonance imaging (MRI) are associated with dementia in PD. For this study, 35 patients with PD, 16 with dementia (PDD) and 19 without (PDND), and 20 control subjects were recruited. MRI scans of patients and controls were rated for WMH, blind to diagnosis, using the Scheltens visual rating scale. Both bivariate and multivariate statistical analyses were carried out. Cerebrovascular risk factors, education, gender, or age were similar across groups. Compared with the PDND group, the PDD group had significantly higher level of WMH in the deep white matter and in the periventricular areas. WMH in the deep white matter was the only variable that was associated significantly with Mini-Mental State Examination score and explained 38% of the variance in the multivariate linear regression analysis. Our findings suggest that WMH in the deep white matter may contribute to dementia in PD.