a degenerative disease of later life, characterized by a rhythmic tremor and muscular rigidity, caused by degeneration in the basal ganglia of the brain
See Parkinson's disease in American Heritage Dictionary 4
(pärˈkĭn-sənz)
noun
A progressive nervous disease occurring most often after the age of 50, associated with the destruction of brain cells that produce dopamine and characterized by muscular tremor, slowing of movement, partial facial paralysis, peculiarity of gait and posture, and weakness. Also called paralysis agitans, shaking palsy.