Response rates and test-retest reliability of ipsilateral and contralateral ocular vestibular evoked myogenic potential in healthy adults

Abstract

Objective: Ocular vestibular evoked myogenic potential (oVEMP) is a widely used clinical tool for assessment of utricular function in vestibular disorders. However, clinical use of this potential has been restricted largely to the contralateral recording alone, possibly because of reports regarding lower response rates with the ipsilateral oVEMP. Therefore, the present study aimed at identifying the incidence and establishing the test-retest reliability of ipsilateral and contralateral oVEMP. Study design: The study included 30 healthy individuals in the age range 18–40 years. Ipsilateral and contralateral oVEMP were recorded in response to alternating polarity 500-Hz tone bursts of 128dB peSPL. Results: The response rates for ipsilateral and contralateral responses were 93.33% and 98.33%, respectively, with no significant difference between the two (p > 0.05). Ipsilateral oVEMP demonstrated significantly longer latencies and smaller peak-to-peak amplitudes than the contralateral oVEMP (p < 0.05). The inter- and intra-session test-retest reliability ranged from moderate to excellent, irrespective of the response type. Conclusion: Considering the latency and amplitude differences, it appears likely that there is a different generator muscle for ipsilateral oVEMP, probably the inferior rectus. Use of the ipsilateral oVEMP could, therefore, open new avenues for studying the functionality of the vestibulo-ocular reflex, providing further physiological evidence in support of this theory.