Ocular vestibular evoked myogenic potentials in facial palsy

Vestibular evoked myogenic potentials which are induced around the eyes are known as ocular vestibular evoked myogenic potentials (oVEMPs) and are useful for the clinical examination of vestibular function. Cervical vestibular evoked myogenic potentials (cVEMPs) have been used as a test of the vestibulo-collic reflex, particularly the sacculo-collic reflex. In Ramsay Hunt syndrome, facial palsy of the eighth cranial nerve spreads from the geniculate ganglion via the vestibulofacial and vestibulocochlear anastomoses. Other studies have also reported that vertigo in patients with Ramsay Hunt syndrome is mostly induced by superior vestibular neuritis. We identified oVEMPs in patients with unilateral facial palsy and analyzed the association of oVEMPs with clinical usefulness, recovery of facial palsy, and pathology of Ramsay Hunt syndrome. Seventeen patients with facial palsy were enrolled in this study. There were 6 cases of Bell's palsy and 11 cases of Ramsay Hunt syndrome. Vertigo in patients with Ramsay Hunt syndrome was induced by superior vestibular neuritis rather than inferior vestibular neuritis, as was indicated by the frequent impairment of oVEMPs. There was a tendency for patients with a low electroneurography (ENoG) value, and patients who had improved slowly, to show abnormal oVEMPs.