Ocular Vestibular Evoked Myogenic Potential in Healthy Subjects: A Comparative Study with Cervical Vestibular Evoked Myogenic Potential / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: While vestibular evoked myogenic potentials (VEMPs) can be measured from extra-ocular muscle as well as cervical muscle, there are uncertainties about the patterns and discomfort level of ocular vestibular evoked myogenic potentials (oVEMPs). This study is to identify the properties of oVEMPs parameters and degree of subjective discomfort when compared to cervical vestibular evoked myogenic potentials (cVEMPs) in healthy subjects. SUBJECTS AND METHOD: Twenty volunteers with normal hearing were enrolled in this study. The oVEMPs were recorded from electrodes placed beneath the eyes using ipsilateral and contralateral acoustic stimulation with 500 Hz short tone bursts with subjects in sitting position and maximal upward gaze. The cVEMPs were measured using 500 Hz short tone bursts with subject in supine position and their head elevated and turned away from the test side. The latency, interlatency and interamplitude of oVEMPs responses were compared to those of cVEMPs. The subjective discomfort levels of oVEMPs and cVEMPs were compared using a questionnaire survey. RESULTS: The cVEMPs appeared as positive-negative biphasic responses in all 40 ears whereas oVEMPs were measured in 27 ears (67.5%) with ipsilateral stimulation and 20 ears (85%) with contralateral stimulation which appeared as negative-positive biphasic responses. The oVEMPs had smaller amplitude than the cVEMPs. The oVEMPs thresholds tended to have higher level than the cVEMPs thresholds. The 18 subjects (90%) reported that the discomfort level of oVEMPs measurement was lower or equal to that of cVEMPs measurement. CONCLUSION: oVEMPs test may be used as a complementary and comfortable diagnostic tool for evaluating the integrity of vestibular-ocular system.