Question: What is Parkinson's Disease? Rev. 02/03
Answer: Parkinson's disease is a chronic, progressive neurodegenerative disease characterized by resting tremor, rigidity, bradykinesia, and postural instability. No known treatment has been proven to halt the progression of Parkinson's disease and there is no cure. First described by James Parkinson in 1817, the disease occurs when cells stop functioning in certain parts of the brain that are responsible for sending signals to other brain regions. An essential chemical messenger, or neurotransmitter, called dopamine is missing in that region of the brain that controls movement. This loss is the primary defect in PD, affecting the nerves and muscles controlling movement and coordination.
Pharmacologic treatment with levodopa and adjunctive drugs can usually restore smooth motor function for up to 5-10 years after onset. Levodopa's effectiveness gradually diminishes with time. Eventually, most patients experience drug-related complications, such as motor fluctuations and dyskinesias. The most severe motor complications of levodopa tend to occur among patients with early onset (i.e., before age 40) Parkinson's disease.
Persons with Parkinson's disease can also exhibit symptoms unrelated to the dopaminergic systems. Thus symptoms that are unresponsive to dopamine-active medications ultimately develop. Such symptoms are dementia, and motor symptoms that affect speech, swallowing, and gait, as well as sleep disturbances, fatigue, and depression.
The disease currently affects an estimated one and a half million people in North America alone. Though the actual cause is unknown, many experts feel it is due to an interaction of genetic and environmental factors.
The greatest risk factor is increasing age, so we expect to see a rise in the incidence of Parkinson's as the population ages.
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