ajus paikneva ekstrapüramidaalsüsteemi haigus, mille kulus on keskne koht kindla aju piirkonna nn. aju must-tuuma närvijätkete, dopamiinergiliste neuronite, süveneval kahjustusel, närvisüsteemi degeneratiivne haigus, millele on iseloomulikud süvenevad värinad, lihaste jäikus ja tasakaaluprobleemid, tundmatu tekkepõhjusega (idio­paatiline) parkinsonism, a chronic progressive neurological disease chiefly of later life that is linked to decreased dopamine production in the substantia nigra and is marked especially by tremor of resting muscles, rigidity, slowness of movement, impaired balance, and a shuffling gait, a progressive, degenerative neurologic disease characterized by a tremor that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression