Differential diagnosis of parkinsonian syndromes: dynamics of time courses are essential.

Differential diagnosis of parkinsonian syndromes encloses idiopathic Parkinson's disease, other primary neurodegenerative diseases (atypical parkinsonism), symptomatic cases, pseudoparkinsonism and inherited forms. Clinical diagnostic criteria are not safe when applied only at disease onset. Diagnostic accuracy can be intensified by recognition of distinct patterns of signs and symptoms and by focussing attention on the time course of the disease.