Optimum Number of Sweeps in Clinical OVEMP Recording; How Many Sweeps are Necessary?

Abstract

Ocular vestibular-evoked myogenic potentials (OVEMPs) in our hands provide us with reproducible and consistent results; however, it has been shown that the OVEMP amplitude decreases with increased stimulus duration. The exact number of stimuli for OVEMP recording is not consistent among the published papers describing this test. We aimed to determine the number of stimuli needed to produce a satisfactory OVEMP response and the consequences of a more prolonged stimulation to the OVEMP response. We retrospectively analyzed 50 OVEMP patient recordings and found that the average number of sweeps carried out was 26. We carried out three different OVEMP recordings using our standard protocol of (1) a "standard" OVEMP protocol, in which we record until the OVEMP wave becomes obvious; (2) an OVEMP recording using our average of 26 sweeps; and (3) an OVEMP recording with twice as many sweeps. OVEMP latencies did not change when using different number of sweeps; however, the amplitudes showed a significant decrease with an increasing number of sweeps. OVEMPs can be completed in a satisfactory manner with a much lower number of stimuli than those usually carried out. Reducing the stimulus number reduces the time taken for the test, minimizes the cochlear insult while not reducing the valuable information obtained, and maximizes the amplitude of the stimulus, possibly increasing the accuracy of measuring interaural amplitudes and helping to measure asymmetry.