What is the definition or description of: parkinson's disease?

Parkinsons disease: Is a degenerative disorder of the central nervous system. The motor symptoms of parkinson's disease result from the death of dopamine-generating cells in the substantia nigra, a region of the midbrain; the cause of this cell death is unknown. Early in the course of the disease, the most obvious symptoms are movement-related; these include shaking, rigidity, slowness of movement and difficulty with.