title: 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.
authors.affiliation: Department of Neurology, National Neuroscience Institute, Singapore. Nagaendran_Kandiah@nni.com.sg
authors.forename: Nagaendran
authors.initials: N
authors.lastname: Kandiah
authors.forename: Elijah
authors.initials: E
authors.lastname: Mak
authors.forename: Amanda
authors.initials: A
authors.lastname: Ng
authors.forename: Shan
authors.initials: S
authors.lastname: Huang
authors.forename: Wing Lok
authors.initials: WL
authors.lastname: Au
authors.forename: Yih Yian
authors.initials: YY
authors.lastname: Sitoh
authors.forename: Louis C S
authors.initials: LC
authors.lastname: Tan
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000473:pathology*; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000473:pathology / Q000523:psychology; D011446:Prospective Studies; D012307:Risk Factors