Acute hearing symptoms as a prodrome of anterior inferior cerebellar artery infarction

Lee, Hyung; Cho, Yong Won; Sohn, Sung Il

Abstract

OBJECTIVES
An acute auditory symptom (AAS) without any other neurological symptoms or signs suggests a lesion in the peripheral auditory system. Blood supply to the peripheral auditory system arises from the internal auditory artery, ordinarily a branch of the anterior inferior cerebellar artery (AICA), therefore a partial ischemia in the AICA distribution may manifest with an AAS and/or vertigo. The aim of this study was to investigate the clinico-radiologic features of patients who presented with an AAS as a prodromal symptom of the AICA infarction.
METHODS
Sixteen consecutive cases of the AICA infarction diagnosed by brain MRI completed a standardized audiovestibular questionnaire and underwent a neurotological evaluation by an experienced neurotologist.
RESULTS
Five patients (31%) had an AAS as a prodrome of the AICA infarction 1-10 days prior to onset of other brainstem and/or cerebellar symptoms. Two types of AAS were found: recurrent transient hearing loss and/or tinnitus (n=3) or a single episode of prolonged hearing loss and/or tinnitus (n=2). The episodic symptoms were brief, lasting only minutes. The tinnitus preceding infarction was identical to the tinnitus experienced at the time of infarction. At the time of the infarction, all patients developed hearing loss, tinnitus, vertigo, and an ipsilateral hemiataxia. The most common affected site was the middle cerebellar peduncle (n=5). Four of 5 patients had an incomplete hearing loss and all patients had an absence of vestibular function to caloric stimulation on affected side, respectively.
CONCLUSIONS
AAS may be a warning sign of an impending pontocerebellar infarction in the distribution of the AICA. The AAS preceding an AICA infarction may result from an ischemia of the inner ear or the vestibulocochlear nerve.