Differentiation of atypical Parkinson syndromes.

In distinction to idiopathic Parkinson's disease (PD), the diagnosis of atypical Parkinson syndromes comprises dementia with Lewy bodies (DLB), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). We set out to write a state-of-the-art guideline as to which investigations and examinations help to differentiate PD vs. atypical Parkinson syndromes in clinical routine.