Background: Bilateral hearing impairment is rare in vertebrobasilar occlusive disease.
Summary of comment: Between 1986 and 1991, we encountered seven patients (four men, three women; median age, 61 years; range, 46-71 years) who had sudden bilateral hearing impairment among 503 patients with vertebrobasilar occlusive disease. The main initial neurological symptoms were sudden bilateral hearing impairment, tinnitus, and vertigo. Acute labyrinthitis or Ménière's disease was the initial diagnosis until subsequent brain stem or cerebellar signs appeared. Brain stem auditory evoked potentials were abnormal bilaterally in six patients but had unilateral attenuation of the IV-V complex in the remaining one patient. Computed tomographic scans in all six patients showed multiple hypodense lesions in the brain stem and the cerebellum. Cerebral angiography showed complete occlusion on both vertebral arteries in one patient, occlusion on the left with small caliber on the right in another, and severe stenosis on both sides in a third. There was no opacification of internal auditory arteries in these three patients. The remaining patient had arteriosclerotic changes with faint opacification of the bilateral internal auditory arteries. Five patients had a poor prognosis, with locked-in state in four and severe truncal ataxia in one.
Conclusions: We conclude that sudden bilateral hearing impairment in vertebrobasilar occlusive disease is more common than previously recognized and that it may indicate a grave prognosis.