Cerebral white matter hyperintensity in Parkinson's disease: a major risk factor for mild cognitive impairment

Abstract

Background: Mild cognitive impairment (MCI) and dementia contribute to a poor quality of life among patients with PD. The influence of cerebral ischemia as a risk factor for MCI in PD has not been adequately investigated. To address this issue, we examined the influence of the volume and distribution of white matter hyperintensity (WMH) as a risk factor for MCI in early PD.

Methods: Prospective study of patients with early idiopathic PD. All patients had baseline MRI-FLAIR, clinical assessment and detailed neuropsychological evaluation. Data on demographics, vascular risk factors, cognitive performance and WMH volumes were analyzed.

Results: 91 patients; mean age 64.9 years, mean education of 10.5 years. 24 patients fulfilled the Movement Disorder Society criteria for MCI and were classified as PD-MCI while the rest were classified as PD with no cognitive impairment (PD-NCI). Patients with PD-MCI and PD-NCI did not differ in Hoehn & Yahr staging. PD-MCI patients had a higher prevalence of diabetes mellitus, hypertension and hyperlipidemia. PD-MCI patients had significantly greater volume of periventricular (6.04 ml vs. 2.66 ml, p = 0.001) and deep subcortical WMH (2.16 vs.1.44, p = 0.002). Regional WMH was significantly greater among PD-MCI in the frontal, parietal and occipital regions. Logistic regression analyses demonstrated WMH to be associated with PD-MCI independent of age, education, and vascular risk factors. Increasing WMH volume was associated with lower performance on executive function, memory and language.

Conclusions: WMH is an important risk factor for PD-MCI independent of vascular risk factors. PD patients with WMH should be regularly screened for MCI.