[Atypical parkinsonian syndromes].

ATYPICAL PARKINSONIAN SYNDROMES Idiopathic Parkinson's disease is the most common cause of parkinsonism, but in almost 40 % of cases, parkinsonism is due to other causes. The diagnosis of atypical parkinsonian syndromes remains difficult at the early stage. Parkinson's syndrome is associated with other symptoms called «red flags». These red flags need to be identified during the clinical examination. Unlike Parkinson's disease, dopaminergic treatment are slightly effective on motor symptoms. The prognosis is worst, with a faster progression. The life expectation is reduced compared to Parkinson's disease. Diagnosis certainty, given by anatomopathology, is not available during the patient's lifetime. Advances in functional imaging improve diagnosis accuracy. Clinical course answers diagnosis uncertainties in a few month or years. The follow up is multidisciplinary. No treatment is currently available.