A differential diagnosis of Parkinsonism.

Parkinsonism is a common, age-related syndrome, characterized by resting tremor, bradykinesias, rigidity, and postural reflex impairment. Though Parkinsonism is not very difficult to recognize, all Parkinsonism is not created equal and it is important to distinguish among the most common identifiable syndromes. This review discusses the key clinical features of these various syndromes, including Parkinson's disease, progressive supranuclear palsy, multiple system atrophy, corticobasal ganglionic degeneration, Lewy body disease, vascular Parkinsonism, and Parkinsonism with no clear etiology. Symptomatology and diagnostic testing for each syndrome are discussed and 4 typical cases are analyzed to offer clinicians guidance in making a differential diagnosis for Parkinsonism.