title: Motor impairment in PD: relationship to incident dementia and age.
abstract: OBJECTIVE
  To analyze the relationship of specific motor impairment in idiopathic PD to incident dementia.
  
  
  BACKGROUND
  The total Unified PD Rating Scale (UPDRS) motor score at baseline has been associated with an increased risk of developing dementia in PD.
  
  
  METHODS
  A cohort of 214 nondemented community-dwelling patients with PD was followed annually with neurologic and neuropsychological evaluations. The association of baseline motor impairment with incident dementia was analyzed using Cox proportional hazards models. Facial expression, tremor, rigidity, and bradykinesia were analyzed as part of subscore A (indicative of dopaminergic deficiency); speech and axial impairment were analyzed as part of subscore B (indicative of predominantly nondopaminergic deficiency). The correlation between the six motor domains and age was also analyzed.
  
  
  RESULTS
  Of 173 patients followed for at least 1 year, 50 became demented according to the Diagnostic and Statistical Manual of Mental Disorders, revised 3rd edition (DSM III-R) criteria (mean follow-up, 3.6 +/- 2. 2 years). When both subscores A and B were entered into the Cox model, subscore B was associated with incident dementia (relative risk = 1.19; 95% CI, 1.09 to 1.30; p = 0.0001), in addition to gender, age, and education, whereas subscore A was not (relative risk = 1.03; 95% CI, 0.99 to 1.07; p = 0.19). Of the six motor domains, speech and bradykinesia were associated with incident dementia (p < 0.05), and axial impairment approached significance (p = 0.06). Only axial impairment was correlated with age (correlation coefficient = 0.32; p < 0.001).
  
  
  CONCLUSIONS
  The findings suggest that motor impairment mediated predominantly by nondopaminergic systems is associated with incident dementia in PD. Axial impairment may be the result of a combined effect of the disease and the aging process.
authors.affiliation: Gertrude H. Sergievsky Center, New York, NY 10032, USA.
authors.forename: G
authors.initials: G
authors.lastname: Levy
authors.forename: M X
authors.initials: MX
authors.lastname: Tang
authors.forename: L J
authors.initials: LJ
authors.lastname: Cote
authors.forename: E D
authors.initials: ED
authors.lastname: Louis
authors.forename: B
authors.initials: B
authors.lastname: Alfaro
authors.forename: H
authors.initials: H
authors.lastname: Mejia
authors.forename: Y
authors.initials: Y
authors.lastname: Stern
authors.forename: K
authors.initials: K
authors.lastname: Marder
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging; D015331:Cohort Studies; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology*; D020820:Dyskinesias / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D009519:New York City / Q000453:epidemiology; D016017:Odds Ratio; D010300:Parkinson Disease / Q000453:epidemiology* / Q000503:physiopathology; D016016:Proportional Hazards Models; D012720:Severity of Illness Index; D017678:Sex Distribution