Parkinson's disease makes up about 80 % of cases of Parkinsonism.
It is the ideopathic type of parkinsonism.It was initially described by James Parkinson in 1817 a physcian in London , England. Parkinson's disease is characterized by the the clinical features of resting tremor , rigidity , akinesia or brakykinesia and postural instability or gait problems ( TRAP ) . Other features of Parkinson's disease are reduced facial expression , drooling , fatigue , truoble turning , freezing , balance problems , speech problems , small handwritting , difficulty buttoning , brushing teeth , combing hair , or applying make up .

Parkinson's disease has a gradual onset and progresses slowly.
Juvenile Parkinsonism usually starts before the age of 20 and is familial . Young onset Parkinson's disease starts before age 40. Classic ideopathic Parkinson's disease is commonly diagnosed around the age of 55.

Parkinson's disease affects approxiamately 3% of the elderly population. About 100 000 people in Canada, and about 1 000 000 people are affected in the United States.

Parkinson's disease is due to degeneration of the dopamine containing neurons in the substantia nigra and locus ceruleus in the brainstem.

Diagnosis is by the typical clinical presentation. The brain scans are usually normal.

Treatment: Very early stage Parkinson's disease may not require treatment if the symptoms are not interfering with the patient's activities of daily living. The treatment of Parkinson's disease is primarily pharmacological, although some patients may require surgical intervention. The following medications are used for the treatment of Parkinson's disease: levodopa/carbidopa, dopamine agonists including Pramipexole and Ropinirol. Amantadine, selgiline, trihexyphenidyl are other drugs occasionally used.