Characterizing the frequency tuning properties of air-conduction ocular vestibular evoked myogenic potentials in healthy individuals

Abstract

Objective: Inconsistencies regarding frequency tuning of ocular vestibular evoked myogenic potentials (oVEMP) prompted the present study to aim at characterizing frequency tuning of oVEMP in healthy individuals. Design: Normative study. Study sample: The study was conducted to obtain oVEMP responses from 54 healthy individuals in age range of 18–30 years. The responses were acquired for tone-bursts at octave and mid-octave frequencies from 250 to 2000 Hz from the inferior oblique muscle using contralateral electrode placement. The frequencies were compared for amplitude and threshold. Results: oVEMPs were present in 100% of individuals at or below the frequency of 1000 Hz. The responses had maximum amplitude and lowest thresholds at 500 Hz. There were at least two replicable peak-complexes namely n1-p1 and p1-n2. Both these complexes revealed tuning at 500 Hz. Comparison between the two peak-complexes revealed higher amplitudes and lower thresholds for p1-n2 complex. Conclusions: oVEMPs are tuned to 500 Hz for both peak-complexes, with p1-n2 being more robust. Future studies using the threshold of oVEMP may be better suited to use p1-n2 complex for this purpose, provided vestibular origin of the second complex is proved. Additionally, careful use of tuning property is recommended when evaluating pathological conditions.

Key Words::

• Frequency tuning
• oVEMP
• otolith functions

Acknowledgements

We would like to thank the Director and the HOD Audiology for granting permission to carry out the study. We would also like to thank the participants of the study for their participation and kind cooperation throughout the course of the study.

Declarations of interest: This research paper was presented as a platform paper at the 45th Annual Convention of the Indian Speech and Hearing Association held in Chennai from 1st to 3rd February 2013. The authors report no declarations of interest.