Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative movement disorder that impairs movements, speech and other functions. Classic form of PD which generally becomes apparent after 60 years of age affects about 1% of the population. Another form called YOPD, Young-adult Onset Parkinsonism Disease in 3-50 age goup, is estimated to constitute 5-10% of PD. The Parsi community concentrated in Mumbai is observed to have the highest prevalence of PD. PD is slow progressive and may not become incapacitating for many years.

PD is characterized by motor symptoms and non-motor symptoms. Motor symptoms include tremor, muscular rigidity, bradykinesia (slowness in movements), gait and posture disturbances. Non-motor symptoms include depression, anxiety, cognitive impairment and psychosis. Dementia is common and affects approximately 40% of PD patients during the course of the disease. Dementia is a non-specific illness syndrome in which affected areas include cognition, memory, attention, language, and problem solving.

Degenerative changes occur deep within the midbrain causing loss of nerve cells that secrete neurotransmitter dopamine. Dopamine is a chemical that sends a signal in the brain.

The physician needs to observe the affected person for a while to conclude that the symptoms are consistently present before categorizing them symptoms normal aging. To follow the longitudinal course in patients, one of the rating scales called UPDRS, the Unified Parkinson's Disease Rating Scale is used by the therapists.

Only symptomatic treatments are available. Drugs such as L-dopa or levodopa, dopamine agonists, COMT enzyme inhibitors are in use. Deep brain stimulation surgery once practiced commonly is done only in certain advanced PD subjects.

English physician James Parkinson in 1817 gave a detailed description of several cases of PD in an essay.

Contributor: Duraiswamy Navaneetham PhD.

Temple University School of Medicine

Philadelphia, PA, USA

September 2009