title: The frequency and associated risk factors for dementia in patients with Parkinson's disease.
abstract: OBJECTIVE
  To estimate the frequency and determine the risk factors for incident dementia in community-dwelling patients with Parkinson's disease (PD) and in control subjects.
  
  
  METHODS
  Prospective cohort study. During a 3.5-year period, 140 patients with idiopathic PD without evidence of dementia and 572 nondemented control subjects were identified in the community of Washington Heights-Inwood in New York, NY. All subjects underwent neurological and neuropsychological evaluations and follow-up examinations.
  
  
  RESULTS
  Twenty-seven patients with PD (19.2%) became demented throughout 2 years, as compared with 87 (15.2%) of the control subjects. The relative risk (RR) for the development of dementia with PD was 1.7 (95% confidence interval [CI], 1.1 to 2.7) after adjusting for age, education, and gender. Predictive features of incident dementia were an extrapyramidal score greater than 25 (RR, 3.56; 95% CI, 1.4 to 8.9) and a Hamilton Depression Rating Scale score greater than 10 (RR, 3.55; 95% CI, 1.6 to 7.9).
  
  
  CONCLUSIONS
  Patients with PD, especially those with severe extrapyramidal signs, have almost twice the risk for the development of dementia than do community-dwelling control subjects.
authors.affiliation: Gertrude H. Sergievsky Center, Department of Neurology, College of Physicians and Surgeons, New York, NY, USA.
authors.forename: K
authors.initials: K
authors.lastname: Marder
authors.forename: M X
authors.initials: MX
authors.lastname: Tang
authors.forename: L
authors.initials: L
authors.lastname: Cote
authors.forename: Y
authors.initials: Y
authors.lastname: Stern
authors.forename: R
authors.initials: R
authors.lastname: Mayeux
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003704:Dementia / Q000209:etiology* / Q000523:psychology; D003866:Depressive Disorder / Q000150:complications / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology; D011446:Prospective Studies; D012307:Risk Factors