Motor and non-motor features of Parkinson's disease that predict persistent drug-induced Parkinsonism

James F. Morley, Stephanie M. Pawlowski, Adhithi Kesari, Ivy Maina, Alexander Pantelyat, John E. Duda

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)738-742
Number of pages5
JournalParkinsonism and Related Disorders
Issue number7
StatePublished - Jul 2014
Externally publishedYes


  • Drug-induced parkinsonism
  • Non-motor symptoms
  • Olfactory dysfunction
  • Parkinson's disease

ASJC Scopus subject areas

  • Neurology
  • Geriatrics and Gerontology
  • Clinical Neurology


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