Abnormal cervical vestibular-evoked myogenic potential in anterior inferior cerebellar artery territory infarction: frequency, pattern, and a determinant.

BACKGROUND: There has been no systematic study that carefully investigates the characteristic features of abnormal cervical vestibular-evoked myogenic potential (cVEMP) response associated with the AICA territory infarction.

OBJECTIVES: To investigate the frequency, the characteristic patterns of abnormal cVEMP associated with AICA territory infarction, and the crucial site for producing abnormal cVEMP response in the AICA territory infarction.

METHODS: We studied 16 consecutive cases of unilateral AICA territory infarction diagnosed by brain MRI. VEMP was induced by a short click sound and was recorded in contracting sternocleidomastoid muscle. Each patient underwent a quantitative audiovestibular evaluation, including bithermal caloric test and pure tone audiogram.

RESULTS: Eight patients (50%) exhibited abnormal cVEMP response on the side of the AICA territory infarction. All patients with abnormal cVEMP showed an absent or decreased response in amplitude but no difference in latency. Patients with abnormal VEMP were significantly more likely to have canal paresis (CP), sensorineural hearing loss, or both compared with patients who had normal cVEMP. Conversely, abnormal cVEMP was more frequently observed among patients with CP than among those without CP. There was no difference in lesion sites according to brain MRI among patients with or without abnormal cVEMP response.

CONCLUSIONS: Our findings suggest that the peripheral vestibular structure with the inner ear probably plays a crucial role in producing abnormal cVEMP response associated with AICA territory infarction.