Sudden Deafness and Anterior Inferior Cerebellar Artery Infarction

ABSTRACT

BACKGROUND AND OBJECTIVES: Acute ischemic stroke in the distribution of the anterior inferior cerebellar artery (AICA) is known to be associated with vertigo, nystagmus, facial weakness, and gait ataxia. There have been few reports on deafness associated with the AICA infarction. Furthermore, previous neurological reports have not emphasized the inner ear as a localization of sudden deafness. The aim of this study was to investigate the incidence of deafness associated with the AICA infarction and the sites predominantly involved in deafness. MATERIALS AND METHOD: During two years we prospectively identified 12 consecutive patients with unilateral AICA infarction diagnosed by brain MRI. Pure tone audiogram, speech discrimination testing, stapedial reflex testing, and auditory brainstem responses were performed to localize the site of lesion in the auditory pathways. Electronystagmography was also performed to evaluate the function of the vestibular system. RESULTS:The most common affected site on brain MRI was the middle cerebellar peduncle (11). Four patients had vertigo and/or acute auditory symptoms such as hearing loss or tinnitus as an isolated manifestation from 1day to 2 months prior to infarction. Audiological testings confirmed sensorineural hearing loss in 11 (92%) patients, predominantly involved the cochlea in 6 and retrocochlear in 1. The other 4 patients had a severe to profound hearing loss most likely of cochlear origin. Electronystagmography demonstrated no response to caloric stimulation in 10 (83%) patients. CONCLUSIONS: In our series, sudden deafness was an important sign for the diagnosis of the AICA infarction. Audiological examinations suggest that sudden deafness in AICA infarction is usually due to dysfunction of the cochlea, resulting from ischemia to the inner ear.