Abstract

It is known that about 30% of patients with sudden hearing loss present with vertigo or dizziness. In clinical practice, this is called sudden hearing loss with vertigo (SHLV) although definite diagnostic criteria have not been established. Dizziness in SHLV is known to be caused by the dysfunction of the vestibular end-organs as well as the superior vestibular nerve or both vestibular nerve divisions. Lesions of the inferior vestibular nerve or a single semicircular canal have also been reported in these patients. Herein we report a 71-year-old male patient with SHLV who demonstrated vestibular dysfunction involving only the posterior semicircular canal. The patient showed normal results in the bithermal caloric test and the cervical vestibular evoked myogenic potentials test as well as positional test. Video head impulse test showed decreased gain only in the posterior semicircular canal. This case is significant in showing that dizziness in SHLV patients can occur by an abnormality involving only a single semicircular canal.

• Keywords: sudden sensorineural hearing loss; vertigo; posterior semicircular canal