Affiliations: [a] German Center for Vertigo and Balance Disorders - IFB LMU, Ludwig-Maximilians-University Munich, Munich, Germany
| [b] Institute for Neuroradiology, Ludwig-Maximilians-University Munich, Munich, Germany
| [c] UCL Ear Institute, 332 Gray’s Inn Road, London, WC1X 8EE, United Kingdom
Correspondence:
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Corresponding authors. Markus Drexl, Present address: Department Biologie II, Ludwig-Maximilians-Universitaet München, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany. Tel.: +49 (0)89 2180 74340; E-mail: markus.drexl@med.uni-muenchen.de.
Note: [1] Contributed equally.
Abstract: BACKGROUND:Sound is not only detected by the cochlea, but also, at high intensities, by the vestibular system. Acoustic activation of the vestibular system can manifest itself in vestibular evoked myogenic potentials (VEMPs). In a clinical setting, VEMPs are usually evoked with rather high-frequency sound (500 Hz and higher), despite the fact that only a fraction of saccular and utricular hair cells in the striolar region is available for high-frequency stimulation. OBJECTIVE:As a growing proportion of the population complains about low-frequency environmental noise, including reports on vestibular symptoms, the activation of the vestibular system by low-frequency sound deserves better understanding. METHODS:We recorded growth functions of oVEMPs and cVEMPs evoked with air-conducted sound at 120 Hz and below. We estimated VEMP thresholds and tested whether phase changes of the stimulus carrier result in changes of VEMP amplitude and latency. RESULTS:The VEMP response of the otholith organs to low-frequency sound is uniform and not tuned when corrected for middle ear attenuation by A-weighting the stimulus level. Different stimulus carrier phases result in phase-correlated changes of cVEMP latencies and amplitudes. CONCLUSIONS:VEMPs can be evoked with rather low-frequency sound, but high thresholds suggest that they are unlikely to be triggered by environmental sounds.
