Sudden deafness related to posterior circulation infarction in the territory of the nonanterior inferior cerebellar artery: frequency, origin, and vascular topographical pattern.

AIMS: To investigate the frequency and origin of sudden deafness (SD) associated with the nonanterior inferior cerebellar artery (non-AICA) territory posterior circulation infarct(s), and the vascular topographical patterns of ischemic lesion associated with SD.

METHODS: A total of 685 consecutive cases of vertebrobasilar ischemic stroke diagnosed by brain MRI from acute stroke registry were studied.

RESULTS: Seven consecutive patients (1.0%) were identified as having SD as a symptom of non-AICA territory vertebrobasilar ischemic stroke. Audiological testing confirmed sensorineural hearing loss, predominantly cochlear in 4 patients and combined on the affected side cochlear and retrocochlear in 3 patients. Five patients had an isolated cerebellar infarct in the territory of the medial branch of the posterior inferior cerebellar artery and other 2 had infarct in the brainstem. In all, SD was on the side of infarct, as shown on brain MRI. Six patients had accompanied canal paresis to caloric stimulation on the side of SD.

CONCLUSIONS: SD due to non-AICA territory infarction was mostly associated with infarct in the territory of the posterior inferior cerebellar artery. From the known variation of the anatomy of the internal auditory artery and results of audiovestibular evaluations, SD due to non-AICA territory infarct probably results from the damage to the inner ear.