Audiovestibular loss in anterior inferior cerebellar artery territory infarction: a window to early detection?

Acute audiovestibular loss is a common neurotological condition that is characterized by sudden onset of severe prolonged (lasting days) vertigo and hearing loss and is diagnosed by the presence of canal paresis to caloric stimulation and sensorineural hearing loss on pure tone audiogram. Before 2000, papers on anterior inferior cerebellar artery (AICA) territory infarction focused mostly on associated brainstem and cerebellar findings, without a detailed description of neurotological findings. Since 2000, several reports have demonstrated that acute audiovestibular loss is an important sign for the diagnosis of AICA territory infarction. To date, at least eight subgroups of AICA infarction have been identified according to the pattern of neurotological presentations, among which the most common pattern of audiovestibular dysfunction is the combined loss of auditory and vestibular functions. Because audiovestibular loss may occur in isolation before ponto-cerebellar infarction involving AICA distribution, audiovestibular loss may serve as a window to prevent the progression of acute audiovestibular loss into more widespread areas of infarction in posterior circulation (mainly in the AICA territory). Clinician should keep in mind that acute audiovestibular loss may herald impending AICA territory infarction, especially when patients had basilar artery occlusive disease presumably close to the origin of the AICA on brain MRA, even if other central signs are absent and MRI does not demonstrate acute infarction.