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DOI: 10.1055/s-0042-1746880
Characterization of medial olivocochlear reflex in auditory brainstem response- measurement and subject-related factors
Introduction The medial olivocochlear reflex (MOCR) is part of the binaural processing strategies and influences the efferent auditory pathway. Activation by contralateral noises has an inhibiting impact on the cochlear amplifier. Otoacustics emissions are an established method to visualize the reflex, however, this technique is yielding some methodical disadvantages. Visualizing the MOCR via auditory brainstem response (ABR) could be an interesting alternative.
Methods 26 normal hearing individuals were included (median-age 28.81). First, waveform-profiles of ABR were recorded on the left side by using click intensities of 50/60/70 dB with and without simultaneous contralateral noise (60 dB). Amplitudes of waveforms I-V with and without contralateral noise were compared. Afterwards measurement settings were rearranged on the right side and process was repeated.
To evaluate potential influences of time factors and order of setups, ABR was started time-shifted on right side for eight probands.
Results If contralateral noise was present at a sound intensity of 70 dB on the right side and recordings started on the left side, a statistically significant reduction on waveform V amplitude could be recorded (p=.003). When measurements continued with recordings on the right side the effect was no longer detectable. Effects could not be observed if starting conditions were reversed left to right (p=.844). However, a reduction of waveform II was observed at a sound intensity 70 dB (p=.047). 15.5% of probands were left-handed; in these cases, no suppression effect was observed.
Discussion Visualization of MOCR via ABR is possible. Chronological orders influence the impact of this effect. Contralateral suppression might be more powerful in right-handed probands
Das Projekt wurde von Cochlear Research and Development Limited finanziell unterstützt
Publication History
Article published online:
24 May 2022
© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).
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