A 75-year-old woman presents two hours after she experienced sudden-onset dizziness and vomiting. These symptoms started when she sat up in bed, after waking up in the morning; and subsided completely after a few minutes. She is symptom-free right now. However, the symptoms recur for a minute or two whenever she turns her head, and subside when she stays still. She describes the dizziness as “feeling like the room is spinning around her”. There is no tinnitus or hearing loss. Neither is there headache, visual disturbances, focal weakness, or impairment of sensation. Her medical history is only significant for well-controlled hypertension.