Parkinsonism (also known as Parkinson's syndrome, a typical Parkinson's, or secondary Parkinson's) is a neurological syndrome characterized by tremor, hypokinesia, rigidity, and postural instability

Parkinson disease is recognized as one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years. There are 2 major neuropathologic findings: the loss of pigmented dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of Lewy bodies (see the following image). Most cases of Parkinson disease (idiopathic Parkinson disease [IPD]) are hypothesized to be due to a combination of genetic and environmental factors. However, no environmental cause of Parkinson disease has yet been proven. A known genetic cause can be identified in approximately 10% of cases, and these are more common in younger-onset patients.

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It is an extra pyramidal disorder of the Basal ganglioncausing
1. Tremors
2. Rigidity- lead pipe or cog-wheel
3.Bradykinesia-slowness of movements
4. Loss of associated movements
5. Mask facies
6. Slow shuffling gait-if if trying to catch the centre of gravity

Paralysis agitans: a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination.