Electrode Montage Induced Changes in Air-Conducted Ocular Vestibular-Evoked Myogenic Potential

Objectives: Stimulus and recording parameters are pivotal for shaping the ocular vestibular-evoked myogenic potential (oVEMP). In the last decade, several attempts were made to identify the optimum electrode placement site to improve the oVEMP responses. A vast majority of these found larger response amplitudes for alternate electrode montages like belly-tendon (BT), chin-referenced (CR), and/or sternum-referenced montages than the clinically used infra-orbital montage. However, no study has yet compared all alternate electrode montages in a simultaneous recording paradigm to eliminate other confounding factors. Also, no study has compared all of them for their test-retest reliability, waveform morphology, and signal-to-noise ratio. Therefore, the decision on which among these electrode montages is best suited for oVEMP acquisition remains opaque. The present study aimed to investigate the effects of various electrode montages on oVEMP's response parameters and to determine the test-retest reliability of each of these in clinically healthy individuals using a simultaneous recording paradigm. Design: This study had a within-subject experimental design. Fifty-five young healthy adults (age range: 20-30 years) underwent contralateral oVEMP recording using infra-orbital, BT, chin-referenced, and sternum-referenced electrode montages simultaneously using a four-channel evoked potential system. Results: BT montage had a significantly shorter latency, larger amplitude, higher signal-to-noise ratio, and better morphology than other alternate montages (p < 0.008). Further, all electrode montages of the current study showed fair/moderate to excellent test-retest reliability. Conclusions: By virtue of producing significantly better response parameters than the other electrode montages, BT montage seems better suited to the recording of oVEMP than the known electrode montages thus far.