ENG, sinusoidal vertical-axis rotation testing, and MRI in a patient with disequilibrium and nausea.

A 46-year-old man presented with a 2-month history of an intermittent dizzy feeling ("as if I'm in a fog") and lightheadedness. His symptoms manifested regardless of whether he was lying down, sitting, standing, or walking. He also experienced nausea, which was usually associated with the dizziness and which sometimes led to vomiting. In fact, during a recent airplane flight, he had experienced a significant amount of vomiting. He had no subjective hearing loss and no tinnitus. Since the onset of his symptoms, he had noticed some intermittent aural fullness in the right ear, which occurred in the morning.

A clinical neurotologic examination revealed the presence of a left hemifacial tic that had not been noticed by the patient or his wife. In addition, the patient experienced difficulty performing the sharpened tandem Romberg test, particularly with the left foot forward. His cerebellar function was normal. Findings on audiologic testing--including speech, speech-in-noise, acoustic immittance, and oto-acoustic emissions studies--were within normal limits.

Electronystagmography (ENG) revealed a direction-changing positional nystagmus, a 35% reduced vestibular response (RVR) left on alternate binaural bithermal caloric testing, and a type 2 response that revealed the RVR left on simultaneous binaural bithermal testing (figure 1). Sinusoidal vertical-axis rotation testing showed normal gains, symmetry, and phases (figure 2).

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In light of the hemifacial tic and ENG findings, magnetic resonance imaging (MRI) was performed. The MRI detected a 5-cm cystic lesion in the cerebellar vermis (figure 3). The radiologist indicated that this type of lesion is typical of a cerebellar hemangioblastoma. The lesion was located to the left of the midline, possibly explaining the facial tic and ENG findings.

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The lesion was removed surgically. At 7 months postoperatively, the patient's symptoms had dissipated dramatically, although not completely; he still experienced some mild instability.

Kenneth H. Brookler, MD, and Mohamed A. Hamid, MD, PhD

From Neurotologic Associates, PC, New York City (Dr. Brookler), and the Cleveland Hearing and Balance Center, Beachwood, Ohio (Dr. Hamid).