Parkinson's disease symptoms were first described in 1817 by the English physician James Parkinson. It affects about one million people in the United States. It usually strikes after age 50, and is characterized by tremor, rigid movement, slowed gait, and stooped posture.
People with Parkinson's disease have low levels of dopamine, a neurotransmitter that helps coordinate muscle activity. Dopamine usually inhibits nerve activity, so without it nerve pathways can overload. These excess signals can overexcite the muscles, causing them to stiffen and "lock-up", as might a computer attempting to run too many programs at once.
While the cause of Parkinson's disease remains largely unexplained, research findings implicate environmental toxicants. Recent thinking also emphasizes the significance of gene/environment interactions. Several laboratories in the University of Washington Department of Environmental and Occupational Health Sciences are probing those connections.
- ENV H 571 Neuroepidemiology and Environmental Risk Factors