title: Motor and non-motor features of Parkinson's disease that predict persistent drug-induced Parkinsonism.
abstract: BACKGROUND
  Drug-induced Parkinsonism is common, causes significant morbidity, and can be clinically indistinguishable from idiopathic Parkinson's disease. Additionally, drug-induced Parkinsonism may, in some cases, represent "unmasking" of incipient Parkinson's disease. Clinical features or tests that distinguish degenerative from pharmacologic Parkinsonism are needed.
  
  
  METHODS
  We performed a retrospective case-control study of 97 drug-induced Parkinsonism subjects and 97 age-matched patients with Parkinson's disease. We compared the frequency of subjective motor and non-motor complaints, objective motor findings (Unified Parkinson's Disease Rating Scale Part III) and, where available, objective olfactory tests. We also performed a nested case-control study wherein we compared these same features between drug-induced Parkinsonism patients based on whether or not they recovered after changing the offending agent.
  
  
  RESULTS
  Non-motor symptoms including constipation and sexual dysfunction were more common in Parkinson's disease than in drug-induced Parkinsonism. While total motor scores were similar between groups, Postural Instability-Gait Difficulty scores were also higher in Parkinson's disease. Features that were significantly different or showed a trend towards significance in both comparisons included subjective loss of facial expression, dream-enactment behavior, autonomic complaints and Postural Instability-Gait Difficulty scores. Hyposmia was more common in Parkinson's disease and was strongly predictive of persistent drug-induced Parkinsonism after therapy change (odds ratio 30.3, 95% confidence interval: 1.5-500, p = 0.03).
  
  
  CONCLUSIONS
  A constellation of motor and non-motor features may differentiate unmasked Parkinson's disease from drug-induced Parkinsonism. In particular, olfactory testing may offer a simple and inexpensive method to help predict outcomes in drug-induced Parkinsonism and, potentially, identify a cohort of pre-motor Parkinson's disease.
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, USA. Electronic address: James.morley@va.gov.
authors.forename: James F
authors.initials: JF
authors.lastname: Morley
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Pawlowski
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA.
authors.forename: Adhithi
authors.initials: A
authors.lastname: Kesari
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA.
authors.forename: Ivy
authors.initials: I
authors.lastname: Maina
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pantelyat
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Philadelphia VA Medical Center, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Duda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014150:Antipsychotic Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D003248:Constipation / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010302:Parkinson Disease, Secondary / Q000139:chemically induced* / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014202:Tremor / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology
chemical_list: D014150:Antipsychotic Agents
keywords: Drug-induced Parkinsonism; Non-motor symptoms; Olfactory dysfunction; Parkinson's disease