Parkinson's disease is a degenerative disorder of the human nervous system. As a result of the death of dopamine-generating cells in the midbrain, movement-related symptoms begin to appear, including body shaking, difficulty with walking and slowness of movement. The disease progresses to include behavioral problems and thinking problems, often including dementia.
Most cases of Parkinson's disease occur after the age of 50, and there is yet no known cause for the cell death in the midbrain. Motor symptoms collectively are known as Parkinsonism. Early stages of the disease are effectively managed through medications such as L-DOPA and dopamine agonists. Parkinson's disease is named after James Parkinson, who originally wrote a paper in 1817 describing six cases of what he called paralysis agitans, although characteristics of the disease can be traced in historical records to the ancient world. Notable cases of people suffering from Parkinson's include actor Michael J. Fox and former boxer Muhammad Ali.
Inevitably, the symptoms of Parkinson's increase over time. Motor symptoms especially will advance in an aggressive fashion if not treated. Parkinson's reduces life expectancy, especially as dementia risks increase, and medication efficacy wanes. Parkinson's is the second-most common neurodegenerative disorder in the world after Alzheimer's. April 11, James Parkinson's birthday, has been chosen as Parkinson's disease day, designed to raise awareness of the disease.