Atypical Parkinsonian Disorders.

Atypical parkinsonian disorders (APD) include progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy. Identifying APD is important because they have different pathogenesis, disease course, and prognosis than Parkinson's disease (PD), and require different treatments. Therefore, when encountering patients with parkinsonism, it is of crucial importance to look for "red flags" or signs, such as impairments in higher cortical function, visuomotor system, cerebellar and other motor abnormalities including dystonia, myoclonus, and apraxia that help differentiate them from PD. Although disease-modifying therapies are not yet available, treatments targeting specific symptoms may improve the quality of life in these patients.