Appraisal of the signal-to-noise-ratio of uni- and bipolar recordings of ocular vestibular evoked myogenic potentials

Ocular vestibular evoked myogenic potentials (oVEMPs) are a non-invasive method to investigate otolith function me- diated via the superior vestibular nerve. However, the herein used recordings and protocols may alter within different studies. In particular the diverging use of electrode configuration regarding polarity or even electrode position varies across studies. There- fore, a systematic analysis and appraisal of the different electrode configuration seems mandatory. In this study we compared the quality of uni- and bipolar recordings based on the signal to noise ratio (SNR). We recoded oVEMPs using a uni- and bipolar electrode configuration simultaneously and compared the recorded amplitudes and latencies and calculated the SNR. The am- plitudes recorded by the unipolar configurations were significantly ( p< 0.01) increased compared to the bipolar configuration. However, the SNR of the bipolar setup was significantly better ( p< 0.05) when compared to the unipolar setup. Additionally, we estimated a transfer function that enabled a comparison of uni- and bipolar recordings. To conclude, the variety of setups used for oVEMP recording hinder a comparison of results and unipolar electrode configurations have clear disadvantages.