What is Parkinson's Disease?
Parkinson's disease is a progressive neurological condition that affects over one-million people in the United States. Approximately 60,000 people are newly diagnosed each year. Onset commonly occurs after age sixty, however up to ten percent will receive an earlier diagnosis and are considered to have Young Onset Parkinson's.
Parkinson's is characterized by motor problems including slowness of movement, rigidity, and tremor. Balance and gait problems may occur later in the course of illness. Some people may also experience a decrease in facial expression, low voice volume, small handwriting, and difficulty with fine motor movements. A number of non-motor symptoms are associated with Parkinson's including depression and other emotional changes; difficulty in swallowing, chewing, and speaking; urinary problems or constipation; skin problems; and sleep disruptions. It is important to understand that symptoms vary from person to person. The American Parkinson Disease Association (APDA) Parkinson's Disease Handbook provides an expanded description of signs and symptoms.
What Causes Parkinson's Disease?
The cause of Parkinson's disease is unknown at this time. Motor symptoms result from the loss of pigmented neurons or cells in the substantia nigra of the brain. These cells produce dopamine, a chemical responsible for smooth purposeful movement. A decrease in dopamine does not account for all symptoms experienced in PD. Research is ongoing to better understand the pathology of Parkinson's.
In some people the onset of non-motor symptoms—including a decrease in smell, REM Behavior Disorder, and constipation—can occur years before the onset of motor symptoms. This knowledge may provide clues which will hopefully lead to better treatments earlier in the course of the disease. Significant research to better understand the genetics of Parkinson's and the role played by the environment is ongoing. APDA has supported many of these research initiatives.
Currently there is no diagnostic test or biological marker that confirms a diagnosis of Parkinson's. Diagnosis is based on medical history and physical examination performed by an experienced practitioner. Seeing a physician who specializes in the care of Parkinson's patients (a neurologist who is a movement disorder specialist or a general neurologist) has been proven to provide some of the best outcomes for a patient.