Parkinson's Disease

Parkinson's disease (PD; paralysis agitans; also known as Parkinson disease in the U.S.) is a neurodegenerative disease of the substantia nigra, an area in the basal ganglia of the brain. The disease was first recognised and its symptoms documented in 1817 in An Essay on the Shaking Palsy by the British physician Dr James Parkinson; the associated biochemical changes in the brain of patients were identified in the 1960s. Some gene defects associated with the disease were identified only recently; others remain unknown.

The disease involves a progressive disorder of the extrapyramidal system, which controls and adjusts communication between neurons in the brain and muscles in the human body. It also commonly involves depression and disturbances of sensory systems.

Parkinson's disease is widespread, with a prevalence estimated between 100 and 250 cases per 100,000 in North America; globally prevalence estimates range from a low of 15 per 100,000 in China to a high of 657 per 100,000 in Argentina. Because prevalence rates can be affected by socio-economically driven differences in survival, incidence is a more sensitive indicator: rates have ranged from 1.5 per 100,000 in China to a high of 14.8 per 100,000 in Finland. [BC Medical Journal Volume 43, Number 3, April 2001, 133-137 Epidemiology of Parkinson’s disease Benjamin C.L. Lai, MD, MSc, and Joseph K.C. Tsui, MD, FRCP(UK), FRCPC]

About 2% of the population develops the disease some time during life, though the mean age at onset is 58-60. Symptoms usually begin in the upper extremities, and are usually unilateral (one-sided) or asymmetrical at onset.

Wikipedia Parkinson's Page