Characteristics and clinical applications of ocular vestibular evoked myogenic potentials

Recently, ocular vestibular evoked myogenic potentials (oVEMPs) have been described and added to the neuro-otologic test battery as a new measure for the vestibulo-ocular reflex. oVEMPs represent extraocular muscle activity in response to otolith stimulation e.g. by air-conducted sound or bone-conducted vibration. In response to vestibular stimulation, electromyographic activity of the extraocular muscles can be recorded by means of surface electrodes placed beneath the contralateral eye. oVEMPs are likely to reflect predominantly utricular function, while the widely established cervical vestibular evoked myogenic potentials (cVEMPs) assess saccular function. Thus, measuring oVEMPs and cVEMPs in addition to caloric and head impulse testing provides further evaluation of the vestibular system and enables quick and cost-effective assessment of otolith function. This review summarizes the neurophysiological properties of oVEMPs, gives recommendations for recording conditions and discusses oVEMP alterations in various disorders of the vestibular system. With increasing insight into oVEMP characteristics in vestibular disorders, e.g. Menière's disease and superior semicircular canal dehiscence syndrome, oVEMPs are becoming a promising new diagnostic tool for evaluating utricular function.