Purpose of Review: While establishing the diagnosis of Parkinson disease (PD) can be straightforward, it can be challenging in some patients, even for the experienced neurologist. The misdiagnosis rate ranges from 10% to 20% or greater depending on clinician experience.
Recent Findings: Despite promise in the search for a biomarker that can establish the presence of PD and act as a marker of its progression, the diagnosis of PD continues to be based on clinical examination. Core criteria, exclusion criteria, and supportive criteria have been developed to aid the clinician in establishing the diagnosis. Nonmotor symptoms of PD are usually present at the time of diagnosis, may precede motor symptoms, and should be specifically sought during evaluation. Ancillary testing can be appropriate, but its indications and utility must be clearly understood.
Summary: The diagnosis of PD requires the recognition of the core features of PD and the differentiation of its clinical presentation from other entities with similar and potentially overlapping symptoms. A careful history and examination guided by clinical diagnostic criteria will usually establish the diagnosis of PD or uncover red flags for the possibilities of other diagnoses. Appropriate selection and interpretation of ancillary testing is critical to avoid misdiagnosis and unnecessary tests.
Address correspondence to Dr Christopher W. Hess, University of Florida Health Center for Movement Disorders and Neurorestoration, 3450 Hull Rd, Gainesville, FL 32607, Christopher.Hess@neurology.ufl.edu.
Relationship Disclosure: Dr Hess has received personal compensation as a speaker for the Davis Phinney Foundation and the National Parkinson Foundation, has received grant support from the University of Florida, and has participated in CME and educational activities on movement disorders sponsored by Allergan, Ipsen, Mertz Pharma, PeerView Press, and QuantiaMD. Dr Okun serves as a consultant for the National Parkinson Foundation and has received research grants from the Bachmann-Strauss Dystonia & Parkinson Foundation Inc, the Michael J. Fox Foundation, the National Institutes of Health, the National Parkinson Foundation, the Parkinson Alliance, Smallwood Foundation, the Tourette Association of America, Tyler’s Hope, and the University of Florida Foundation. Dr Okun has participated as a site principal investigator and coinvestigator for several trials sponsored by the National Institutes of Health and other foundations and industries, but has not received compensation. Dr Okun has received royalties from Amazon.com Inc, Books4Patients LLC, Cambridge University Press, Demos, Manson Publishing Ltd, Smashwords, and Taylor & Francis Group. Dr Okun serves as associate editor for the New England Journal of Medicine Journal Watch Neurology, and has lectured in CME activities for Henry Stewart Conferences & Events, PeerView Press, Prime Education Inc, QuantiaMD, and Vanderbilt University.
Unlabeled Use of Products/Investigational Use Disclosure: Drs Hess and Okun report no disclosures.