[Atypical Parkinson syndrome].

Various clinico-pathological studies have shown that appr. 20% of patients with a clinical diagnosis of idiopathic Parkinson's disease (IPD) may have neuropathological evidence of alternative causes of parkinsonism. Most of these misdiagnosed "IPD" patients meet clinical criteria for either multiple system atrophy (MSA), or progressive supranuclear palsy (PSP), or corticobasal degeneration (CBD). A careful history and physical examination, as well as follow-ups and selected investigations are essential for an accurate clinical diagnosis of these atypical parkinsonian syndromes. The following paper therefore provides a review of clinical features and diagnostic findings in MSA, PSP and CBD, in order to facilitate recognition of these patients.