Non-functioning posterior communicating arteries of circle of Willis in idiopathic sudden hearing loss

Most cases of sudden hearing loss have no identifiable cause. A link between compensatory blood flow through the circle of Willis and recovery from sudden hearing loss has, however, been suggested. We assessed 22 patients with sudden hearing loss who had no cerebrovascular disease, and 41 controls matched for age and sex. We took ultrasonographic doppler flow measurements of the extracranial carotid and vertebrobasilar systems and independent audiological measurements. 12 patients with sudden hearing loss, compared with four controls had bilateral non-functioning posterior communicating arteries (p=0·00019). Our findings suggest a strong association between a non-functioning posterior communicating artery of the circle of Willis and sudden hearing loss.