Ocular vestibular-evoked myogenic potentials elicited from monaural versus binaural acoustic stimulations

Objective: This study compared the ocular vestibular-evoked myogenic potentials (oVEMPs) that are elicited (recorded) in response to monaural and separately, simultaneous binaural acoustic stimulations. The optimal stimulation mode for oVEMPs was also determined. Methods: Twenty healthy volunteers (14 men and 6 women, aged from 22 to 33 years, mean 28 years) without any previous ear disorders were enrolled in this study. Each subject underwent oVEMP testing using monaural acoustic stimulation (Men-oVEMP) with different stimulus intensities, and with bilateral recording. On another day, the same volunteers underwent oVEMP testing using simultaneous binaural acoustic stimulation and bilateral recording (Bin-oVEMP). Results: With 95 dB nHL tone burst stimulation, the biphasic nl-pl waveforms were recorded with maximal amplitudes from the electrodes located below the eyes contralateral to the side of acoustic stimulation while the subject was gazing upward. Significant correlations were identified between Mon-oVEMPs and Bin-oVEMPs with respect to threshold, latencies and amplitude. However, no significant difference existed between Mon-oVEMPs and Bin-oVEMPs in terms of the response rate, threshold, latency or amplitude. Conclusions: The Bin-oVEMP test yields the same information as the Mon-oVEMP test, but the duration of recording in the former is shorter than the latter. Significance: The Bin-oVEMP test may be a more convenient screening tool for evaluating the crossed vestibulo-ocular reflex. (C) 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.