A 37-year-old woman comes to her primary care physician for evaluation of dizziness
and hearing loss
. The patient has had multiple episodes of dizziness lasting between 20 minutes to several hours. These episodes are associated with ringing in the left ear. The patient states, “These episodes are so debilitating I have to lie in bed until they are over. Sometimes the spinning sensation is so intense that I vomit
.” Past medical history is noncontributory. She has not had any recent bacterial or viral infections. Vital signs
are within normal limits, and physical examination reveals no significant findings. Audiometric testing demonstrates low-mid frequency hearing loss in the left ear. Hearing in the right ear is normal. Which of the following is the most likely diagnosis?