Movement Disorders USMLE Step 1 Practice Question
A 58-year-old woman is brought to the clinic by her husband who reports that she has become increasingly clumsy and forgetful over the past 18 months. He notes that she frequently falls backward without warning and has difficulty looking downward, particularly when eating. On examination, she has vertical supranuclear gaze palsy (impaired downward gaze), mild cognitive impairment, and postural instability. She denies tremor and shows only minimal rigidity on examination. Brain MRI demonstrates midbrain atrophy with a characteristic 'hummingbird' sign on sagittal imaging. Vital signs are stable. Which of the following is the most likely diagnosis?
Answer choices
- AMultiple system atrophy with predominant Parkinsonian features
- BProgressive supranuclear palsyCorrect answer
- CCorticobasal degeneration
- DBehavioral variant frontotemporal dementia
- EParkinson disease with cognitive impairment
- FLewy body dementia
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