PD is not by itself a fatal disease, but it does get worse with time. The average life expectancy of a PD patient is generally the same as for people who do not have the disease. However, in the late stages of the disease, PD may cause complications such as choking, pneumonia, and falls that can lead to death. Fortunately, there are many treatment options available for people with PD.
The progression of symptoms in PD may take 20 years or more. In some people, however, the disease progresses more quickly. There is no way to predict what course the disease will take for an individual person. One commonly used system for describing how the symptoms of PD progress is called the Hoehn and Yahr scale.
Hoehn and Yahr Staging of Parkinson's Disease
Stage one: Symptoms on one side of the body only.
Stage two: Symptoms on both sides of the body. No impairment of balance.
Stage three: Balance impairment. Mild to moderate disease. Physically independent.
Stage four: Severe disability, but still able to walk or stand unassisted.
Stage five: Wheelchair-bound or bedridden unless assisted.
Another commonly used scale is the Unified Parkinson's Disease Rating Scale (UPDRS). This much more complicated scale has multiple ratings that measure mental functioning, behavior, and mood; activities of daily living; and motor function. Both the Hoehn and Yahr scale and the UPDRS are used to measure how individuals are faring and how much treatments are helping them.
With appropriate treatment, most people with PD can live productive lives for many years after diagnosis.