Vertigo and the anterior inferior cerebellar artery syndrome.

We present two patients with clinical features of infarction in the distribution of the anterior inferior cerebellar artery (AICA) who had vertigo as an isolated symptom for several months prior to infarction. Both had risk factors for cerebrovascular disease and other episodes of transient neurologic symptoms not associated with vertigo. At the time of infarction they developed vertigo, unilateral hearing loss, tinnitus, facial numbness, and hemiataxia. MRI identified hyperintense lesions in the lateral pons and middle cerebellar peduncle on T2-weighted images. Audiometry and electronystagmography documented absent auditory and vestibular function on the affected side. Since the blood supply to the inner ear and the vestibulocochlear nerve arises from AICA, a combination of peripheral and central symptoms and signs is characteristic of the AICA infarction syndrome. The vertigo that preceded infarction may have resulted from transient ischemia to the inner ear or the vestibular nerve.