Parkinson's Disease Department of Neurology The University of Chicago Medical Center Hospitals



Parkinson's Disease (or Parkinson Disease: PD) was first described in 1817 by Sir James Parkinson, a British physician as a gradually progressive degenerative disorder of the nervous system producing predominantly mobility disability.

Up to 1.6 million people are estimated to have PD in the USA. The prevalence of PD will continue to increase with aging population because the incidence of PD increases exponentially with increasing age. The average age at the onset is in the late 50ís and early 60ís, but PD can affect people under 40.

although the exact causes of PD are not known, researchers have discovered that symptoms occur when certain cells in the brain either die or become impaired and are no longer able to supply a key neurotransmitter (a chemical known as "dopamine") to the part of the brain that controls movement, balance and walking. The brain can compensate for some loss of dopamine, but as the majority of dopamine-producing cells continue to die off and the dopamine level falls below about 20 - 40% of normal level, patients develop noticeable symptoms. Other parts of the brain are involved as well and these may account for symptoms such as the loss of smell, blood pressure control problems, urinary difficulty, constipation, and cognitive and psychiatric problems.