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, 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 mov