[Concept and diagnostic criteria of Parkinson's disease and parkinsonism].

Parkinson's disease (PD) is defined as a neurodegenerative disorder characterized pathologically by degeneration of substantia nigra and locus coeruleus with Lewy bodies in the remaining neurons and clinically by resting tremor, cogwheel rigidity, bradykinesia and loss of postural reflex. Parkinsonism may be defined as those who show at lest two of the major four features characterizing PD. We propose the following diagnostic criteria for PD, i.e., clinical criteria (resting tremor or at least two of the remaining cardinal features of PD), treatment criteria (good response to anti-parkinson drugs), image criteria (essentially normal cerebral MRI), and exclusion criteria (no history of encephalitis or exposure to parkinsonism-inducing substances or drugs). Patients must fulfil all four criteria for the diagnosis.