[Diagnostic criteria of parkinsonian syndromes].

Parkinson's disease constitutes 75p. 100 of all causes of parkinsonism. The disease is defined clinically by the UK Parkinson's Disease Brain Bank (UKPDSBB) which exclude secondary causes of parkinsonism and atypical primary parkinsonian syndromes. Any atypical sign, also commonly known as "red flags", should make the clinician aware of an alternative diagnosis: multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration and parkinsonism associated with dementia such as dementia with diffuse Lewy body disease. Despite progress in designing validated clinical diagnosis criteria, such diseases remain difficult to diagnose in their early course.