Genes have been shown to cause PD in a few families, but these same gene defects do not appear to be involved in cases outside of these families. Most researchers suspect the cause of PD is a combination of genetic susceptibility and environmental exposure, and that the genetic and environmental contributions will vary among different people. Parkinson's disease can be treated with non-pharmacologic treatments, drugs, and surgery. Follow the links below for more detailed information on treatment. Parkinson's disease is a progressive disorder.
Symptoms usually begin on one side, and most often involve an extremity - e.g., tremor in one hand.
The disease progresses slowly, over a decade or more, usually first involving the other extremity on the same side, and then the opposite side. Because of the continued decline in motor ability, a wheelchair may be needed for mobility later in the disease course. Depression is common in late-stage PD, as is anxiety and sleep disturbance. Constipation, increased sweating, urinary incontinence, and male impotence also occur. Because of the progressive loss of substantia nigra cells, the response to drug therapy changes over time, with increased doses required later in the disease.