Ocular Vestibular Evoked Myogenic Potentials and Intralabyrinthine Intravestibular Schwannomas

Intralabyrinthine intravestibular schwannomas are uncommon benign tumors arising from the saccular, the utricular or the lateral and superior ampullary nerves. Diagnosis relies on audiovestibular examination and Magnetic Resonance Imaging; literature reports a delay of 8 years between the onset of symptoms and diagnosis. The aim of this paper is to present a case of intralabyrinthine intravestibular schwannoma in which we included in the diagnostic protocol the Ocular Vestibular Evoked Myogenic Potential (oVEMP) test, a new neurophysiological diagnostic exam that measures utricular function and contralateral superior vestibular nerve afferent fibers. We report the case of a patient presenting with progressive sensorineural hearing loss, dizziness, tinnitus and fullness in the right ear. Audiovestibular examination and MRI were performed to diagnose a right intralabyrinthine intravestibular schwannoma; oVEMPs were absent in the side contralateral to lesion and contributed to the diagnostic process in our patient. oVEMP can provide detailed information on the functionality of the superior and lateral ampullary nerves and the macula of utricle with a precise identification of the affected area. Based on this findings, we discuss the role of oVEMPs in the diagnosis of intravestibular intralabyrinthine schwannoma.