Historians have found evidence of the disease as far back as 5000 B.C. It was first described as "the shaking palsy" in 1817 by British doctor James Parkinson. Because of Parkinson's early work in identifying symptoms, the disease came to bear his name.
In the normal brain, some nerve cells produce the chemical dopamine, which transmits signals within the brain to produce smooth movement of muscles. In Parkinson's patients, 80 percent or more of these dopamine-producing cells are damaged, dead, or otherwise degenerated. This causes the nerve cells to fire wildly, leaving patients unable to control their movements. Symptoms usually show up in one or more of four ways:
This diagram of the brain shows several structures related to Parkinson's disease. Basal ganglia affect normal movement and walking; substantia nigra are types of basal ganglia that produce the neurotransmitter dopamine, which sends messages that control muscles. The globus pallidus is part of a larger structure connected to the substantia nigra affecting movement, balance and walking. The thalamus serves as a relay station for brain impulses, and the cerebellum affects muscle coordination.
Though full-blown Parkinson's can be crippling or disabling, experts say early symptoms of the disease may be so subtle and gradual that patients sometimes ignore them or attribute them to the effects of aging. ...