A 43-year-old female presents to the emergency department (ED) after she woke up with the sensation that the room was spinning and vomited three times at home. She continues to have significant vertigo when she presents to the ED 4 hours later. Her symptoms are worsened by head movement. She has noticed some unsteadiness but is able to walk unaided. When you examine her, she has left-beating horizontal nystagmus with a slight rotatory component to the left.