CC BY-NC-ND 4.0 · Laryngorhinootologie 2018; 97(S 02): S176
DOI: 10.1055/s-0038-1640321
Poster
Otologie: Otology

Intraoperative cochlear microphonic potential in middle ear implanted patients

M Ghoncheh
1   Dept. of Otolaryngology, Hannover Medical School, Hannover and Cluster of Excell, Hannover, Germany
,
S Haumann
2   Dept. of Otolaryngology, Hannover Medical School, Hannover and Cluster of Excell, Hannover
,
T Lenarz
2   Dept. of Otolaryngology, Hannover Medical School, Hannover and Cluster of Excell, Hannover
,
H Maier
2   Dept. of Otolaryngology, Hannover Medical School, Hannover and Cluster of Excell, Hannover
› Author AffiliationsDFG Cluster of Excellence EXC 1077/1 "Hearing4all".
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Introduction:

Active middle ear implants have been used as a treatment for conductive and mixed hearing loss. In this study the possibility of utilizing an intraoperative cochlear microphonic (CM) measurement in Vibrant Soundbridge (VSB) implanted patients for improving the coupling efficiency was investigated.

Method:

Four round window (RW) and seven incus coupling patients were included for intraoperative CM measurements using a Natus Viking platform. The CM response was recorded by a cotton-wick electrode and averaged 100 times. Only measurements with a signal-to-noise ratio higher than 10 dB were assumed valid. During the positioning of the FMT the cotton-wick electrode was not moved. The amplitude of stimuli was decreased in steps of three dB to obtain the CM growth functions. As artifact control the CM response was measured when FMT was loosely coupled. To improve the coupling efficiency in RW implantation the position and applied force was varied by the surgeon. During the process the surgeon was informed continuously until the maximum possible amplitude was identified.

Results:

The CM growth function (Input-output curve) showed a linear behavior at 0.5, 1, 2 and 4 kHz. The control CM amplitude was 15 dB lower compared to the final optimum coupling when the FMT was loosely coupled. In average the effective gain obtained employing CM measurement provided 10 dB improvements compared to the average gain in Busch et al. study (2017) at frequencies ranging from 0.5 to 6 kHz.

Conclusion:

The results imply that the intraoperative CM can be used to determine the coupling efficiency of the round window coupling patients. The audiological results indicated an improved effective gain using CM as an intraoperative tool.



Publication History

Publication Date:
18 April 2018 (online)

© 2018. 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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