Parkinson disease

Claire Henchcliffe MD DPhil (Dr. Henchcliffe of Weill Cornell Medical College received a research grant from Biogen as an investigator; honorariums from Lundbeck, Peptron, Teva and USWorldmeds for her service as an advisory committee member; and speakers’ bureau honorariums from Acadia, GE, Lundbeck and Teva.)
Joseph Jankovic MD, editor. (

Dr. Jankovic, Director of the Parkinson's Disease Center and Movement Disorders Clinic at Baylor College of Medicine, has received research and/or training grants from Adamas, Allergan, Biotie, Civitas/Acorda, Hoffmann-La Roche, Medtronic, Merz, Neurocrine , Nuvelution, Pfizer, Prothena, Psyadon, Revance, and Teva; and has served as a consultant or as an advisory committee member for Adamas, Allergan, Merz, Prothena, Revance, and Teva.

Originally released April 12, 1993; last updated March 10, 2017; expires March 10, 2020

This article includes discussion of Parkinson disease, idiopathic parkinsonism, paralysis agitans, and shaking palsy. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


Parkinson disease is 1 of the most common movement disorders and can be challenging to diagnose and treat. In this article, the author provides an introduction to its clinical features, etiology, pathophysiology, epidemiology, and differential diagnosis. The author reviews current treatment strategies in managing Parkinson disease, including advances in pharmacologic and surgical treatments.

Although Parkinson disease is a chronic progressive neurodegenerative disease, using current clinical management strategies patients can attain an improved quality of life with their disease.

Key points


• Parkinson disease is a neurodegenerative disorder characterized by motor signs of bradykinesia, rest tremor, rigidity, and balance, which also affects cognition, mood, sleep, and autonomic function.


• Parkinson disease is diagnosed clinically, although SPECT imaging may be used to aid in diagnosis, and emerging biomarkers provide promise for earlier diagnosis and monitoring disease progression.


• Multiple genes have been identified that cause Parkinson disease or modify risk, and there is increasing evidence for environmental and dietary factors that modify risk.


• Parkinson disease is progressive, and moreover in most patients, long-term treatment with levodopa is complicated by the gradual emergence of dyskinesias and motor fluctuations.


• Treatment with medications and surgery remains symptomatic, but improve quality of life and lifespan.


• Protective and restorative therapies are under development, but none are currently proven.

Historical note and terminology

James Parkinson, a London physician, first described Parkinson disease in 1817 and recognized its distinctive features of tremor, rigidity, and gait difficulties (Parkinson 1817). Not until 50 years later did Charcot distinguish the hallmark of bradykinesia (Charcot 1879). Brissaud drew attention to midbrain lesions, but Greenfield and Bosanquet performed the most complete delineation of the selective cell loss, depigmentation, and degeneration of the substantia nigra (Brissaud 1895; Greenfield and Bosanquet 1953). In the 1960s, the discovery that dopamine was depleted in Parkinson disease, and that levodopa as the precursor to this neurotransmitter could improve symptoms, was described in landmark studies (Barbeau 1962; Cotzias et al 1967; Hornykiewicz 2001). Soon after, however, it was observed that chronic levodopa treatment produced choreoathetoid movement (dyskinesia) in some patients and that intermittent episodes of parkinsonism recurred during the day (the on-off syndrome) (Cotzias et al 1969). Surgical interventions have a more recent history in Parkinson disease treatment (Jankovic 2001) and are now valuable in managing these motor complications.

The content you are trying to view is available only to logged in, current MedLink Neurology subscribers.

If you are a subscriber, please log in.

If you are a former subscriber or have registered before, please log in first and then click select a Service Plan or contact Subscriber Services. Site license users, click the Site License Acces link on the Homepage at an authorized computer.

If you have never registered before, click Learn More about MedLink Neurology  or view available Service Plans.