Doctor James Parkinson published, “An Essay On The Shaking Palsy” in 1817. In it, he described a set of symptoms that bear his name to this day. Parkinson’s Disease is a disorder affecting the central nervous system. It is slowly progressive with increasing symptom severity. It is chronic, acting sometimes over decades. It is idiopathic, with no proven cause. It is not contagious.

Because it is not contagious, no reporting requirement is in place new cases. Parkinson populations are estimated by statistical methodologies. Annually, there are 480 new diagnoses of PD per one million people. Parkinson’s sub-population estimates run as high as 1.0 % of the total population. Citing the 2000 U.S. census, San Antonio’s population is 1.1 million, the greater Bexar County’s population is 1.4 million, and the US population is 281 million. Accordingly, San Antonio is estimated to have between 5,000 to 10,000 PWP.

Parkinson’s affects all ages; most patients are over 50 years of age. More patients are diagnosed at 60 than any other age. Young-Onset is a widely accepted term for those diagnosed before 50 years of age. Young-Onset cases comprise about 20% of all Parkinson’s diagnoses.
Parkinson's disease is associated with four motor disorders. These hallmarks are:
1. Tremor Incessant shaking of extremities, torso, and face
2. Rigidity Torso and limb inflexibility
3. Bradykinesia Slowed movement
4. Postural Instability Balance problems
Two of these four hallmarks need be present before a PD diagnosis is determined. There is no blood test to determine PD. Other causes must be eliminated before a diagnosis of PD can be made. In making a PD diagnosis, a medical professional evaluates these and other criteria.

How many people are affected?
In the United States, at least 500,000 people are believed to suffer from Parkinson's disease, and about 50,000 new cases are reported annually. These figures are expected to increase as the average age of the population increases. The disorder appears to be slightly more common in men than women. The average age of onset is about 60. Both prevalence and incidence increase with advancing age; the rates are very low in people under 40 and rise among people in their 70s and 80s. Parkinson's disease is found all over the world. The rates vary from country to country, but it is not clear whether this reflects true ethnic and/or geographic differences or
discrepancies in data collection.