Parkinson’s disease (PD) is a degenerative disorder of the central nervous system that impairs motor skills, cognitive processes, and other functions. The most obvious symptoms are motor-related, including tremor, rigidity, slowness of movement, and postural instability. Among non-motor symptoms are autonomic dysfunction and sensory and sleep difficulties. Cognitive and neurobehavioral problems, including dementia, are common in the advanced stages of the disease. PD usually appears around the age of 60, although there are young-onset cases.
PD invariably progresses with time. Motor symptoms, if not treated, advance aggressively in the early stages of the disease and more slowly later. Untreated patients are expected to lose independent ambulation after an average of 8 years and be bedridden after 10 years.
At first disability is related to motor symptoms and specially motor complications. As the disease advances disability is more related to motor symptoms that have a bad response to medication such as swallowing and speech difficulties and walk and balance problems. Finally after ten years most people with the disease have autonomic disturbances, sleep problems, mood alterations and cognitive decline. The average life expectancy of a person with PD is lower than for people who do not have the disease. Mortality ratios are around twice those of unaffected people.
Current treatments are effective at managing the early motor symptoms of the disease, through the use of levodopa, dopamine agonists and MAO-B inhibitors. As the disease advances, however, the continued use of medications leads to a second stage in which the patient develops motor complications called dyskinesias.
Research directions include a search of new animal models of the disease, and investigations of the potential usefulness of gene therapy, stem cells transplants and neuroprotective agents.
The disease is named after English surgeon James Parkinson, who gave the first detailed description of it in “An Essay on the Shaking Palsy” (1817). PD is a costly disease to society. Advocacy actions include April 11, birthday of James Parkinson, as the world’s Parkinson’s disease day, and the use of a red tulip as the symbol of the disease. People with PD who have greatly affected public awareness include Michael J. Fox and Muhammad Ali.