title: Motor symptoms at onset of Parkinson disease and risk for cognitive impairment and depression.
abstract: OBJECTIVE
  To determine whether side and type of initial motor symptoms in Parkinson disease (PD) predict risk for later development of cognitive impairment or depressive symptoms.
  
  
  METHODS
  We recruited 124 non-demented patients with PD to participate in a cohort study of cognitive function and depressive symptoms that used validated neuropsychological tests and a depressive symptom inventory. We first reviewed the patients' charts to determine their initial motor symptom and side of onset, and then classified the patients into 4 groups: right-sided onset tremor, right-sided onset bradykinesia/rigidity, left-sided onset tremor, and left-sided onset bradykinesia/rigidity. We excluded patients with bilateral symptom onset. We used analysis of variance on neuropsychological test performance and depressive symptoms to determine whether group classification affected risk of cognitive impairment or depressive symptoms. We controlled our analyses for disease duration and motor severity as measured by the Unified Parkinson Disease Rating Scale Part III motor score.
  
  
  RESULTS
  There were no differences in any cognitive measure by side and type of initial motor symptoms. The right-sided onset tremor group had the lowest depressive symptom scores, and no patient in any group reported severe depressive symptoms.
  
  
  CONCLUSIONS
  Our findings suggest that patterns of nigral cell loss correlating to the initial side and type of motor symptoms in PD are not related to the risk of later cognitive impairment. By contrast, patients with right-sided onset of tremor seem to have a lower risk of depressive symptoms than patients with other presentations.
authors.affiliation: Departments of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9036, USA. richard.dewey@utsouthwestern.edu
authors.forename: Richard B
authors.initials: RB
authors.lastname: Dewey
authors.forename: Aanchal
authors.initials: A
authors.lastname: Taneja
authors.forename: Shawn M
authors.initials: SM
authors.lastname: McClintock
authors.forename: C Munro
authors.initials: CM
authors.lastname: Cullum
authors.forename: Richard B
authors.initials: RB
authors.lastname: Dewey
authors.forename: Ira
authors.initials: I
authors.lastname: Bernstein
authors.forename: Mustafa M
authors.initials: MM
authors.lastname: Husain
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D003863:Depression / Q000175:diagnosis* / Q000523:psychology; D003866:Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology*; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D011237:Predictive Value of Tests; D012306:Risk; D012720:Severity of Illness Index; D063189:Symptom Assessment