People with motor symptoms, such as involuntary tremor, slowness of movement, and gait difficulty, often first present for evaluation and diagnosis in general neurology offices. Although the first sign in Parkinson disease (PD) at an early stage varies, the diagnosis of PD is often the correct one, simply by taking account of its prevalence. However, confirmation of that diagnosis takes time and serial examinations, and it is increasingly recognized that a fraction of those diagnosed with PD actually have another movement disorder and will therefore have a different neurodegenerative disease at autopsy. 1 In particular, the atypical parkinsonism disorders (APDs), such as multiple system atrophy (MSA), progressive supranuclear palsy, and corticobasal syndrome, as well as vascular parkinsonism, can mimic PD at early stages of the clinical disease. These misdiagnoses are not isolated to the general neurology practice; in fact, when the presentation is unusual or early enough, even moveme...