Parkinson’s disease is a progressive brain disorder that is caused by degeneration of nerve cells in the part of the brain called the substantia nigra, which controls movement. These nerve cells die or become impaired, losing the ability to produce an important chemical called dopamine. Studies have shown that symptoms of Parkinson's develop in patients with an 80 percent or greater loss of dopamine-producing cells in the substantia nigra.
It is estimated that 60,000 new cases of Parkinson’s disease are diagnosed each year, adding to the estimated one to 1.5 million Americans who currently have the disease. There were nearly 18,000 Parkinson’s disease-related deaths in the United States in 2003. While the condition usually develops after the age of 55, the disease may affect people in their 30s and 40s, such as actor Michael J. Fox, who was diagnosed at age 30.
Presently, the diagnosis of Parkinson's is primarily based on the common symptoms outlined above. There is no X-ray or blood test that can confirm the disease. However, noninvasive diagnostic imaging, such as positron emission tomography (PET) can support a doctor's diagnosis. People suspected of having Parkinson's disease should consider seeking the care of a neurologist who specializes in Parkinson's Disease, Movement Disorder specialist.
Conventional methods for diagnosis include: