What is parkinson's disease and how long does it take for symptoms to occur?

Parkinsons: Parkinson's disease is a neurological disease with features of tremors rigidity and hypertonia of muscles. Is due to deficiency of Dopamine in brain. The onset of the deceased can vary patient to patient.

Neurologic disorder: Parkinson's disease is degenerative disorder of the central nervous system.Motor symptoms of parkinson's disease result from the death of dopamine-generating cells in the substantia nigra, a region of the midbrain. Cause of cell death is unknown. Shaking, rigidity, slowness of movement, difficulty in walking and gait, later, thinking and behavioral problems arise, advanced disease dementia.

Loss of neurons: Many issues still not understood but main feature is a progressive loss/lack of replacement of neurons in a portion of the mid-brain called the substantia nigra. Like most degenerative diseases, it usually progresses for decades before symptoms become apparent: shaking, rigidity, slowness of movement & difficulty with walking; altered stooped & slow gait.