The effects of commonly used upward gaze angles on ocular vestibular evoked myogenic potentials.

OBJECTIVE

Ocular vestibular evoked myogenic potentials (oVEMP) represent extraocular muscle activity in response to vestibular stimulation. oVEMP amplitudes are known to be modulated by gaze elevation. However, it is not well known to which extent oVEMP are modulated by upward gaze. We thus investigated the effects of commonly used upward gaze angles on oVEMP amplitudes and latencies.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center for vestibular disorders.

SUBJECTS

Thirty-two healthy subjects were enrolled in this study.

INTERVENTIONS

500 Hz air-conducted tone bursts were used to elicit oVEMP with the subject maintaining 30 and 35 degrees and maximal upward gaze, respectively.

MAIN OUTCOME MEASURES

Amplitudes and latencies of oVEMP responses.

RESULTS

n1-p1 amplitudes significantly increased with increasing gaze angle from 30 to 35 degrees. Maximal up-gaze, however, did not result in further enlargement of amplitudes. Latencies were not affected by gaze elevation.

CONCLUSION

A small increase in upward gaze angle caused a considerable augmentation of amplitudes. Controlling the level of gaze when recording oVEMP is thus indispensable to ensure interindividual and intraindividual comparability of oVEMP results.