Experimental comparison between forward and reverse Vibrant Soundbridge cochlear stimulation.
Publisher DOI
PubMed ID
41520501
Abstract
Introduction
Various couplers exist for the Vibrant Soundbridge implant to connect the actuator to a middle ear structure. While the surgical indication mainly distinguishes between purely sensorineural hearing loss and mixed hearing loss, and audiological indication ranges are designed accordingly, we believe that the biomechanical distinction between forward and reverse cochlear stimulation is more meaningful. To evaluate this, we apply all common couplers in temporal bone experiments and correct the measurements for adequate comparability.Material And Methods
The study was conducted at two research labs, each with n = 10 cadaveric temporal bones. Laser Doppler velocity measurements on the stapes were used for direct comparison between the coupling methods. Therefore, reverse cochlear stimulation requires a correction factor due to pressure loss through a third window. This was calculated by measuring intracochlear pressure differences in the same specimens.Results
Compared to the stapes LDV measurement, reverse stimulations require a correction factor that continuously decreases in the high frequency range: approximately +22.4 dB between 125-250 Hz, +7.9 dB between 300-800 Hz, and +4.8 dB above 1000 Hz. Taking this into account, there is still a considerable difference between the forward and reverse stimulation methods of 15-22 dB in the frequency range <2000 Hz and approximately 7 dB >2000 Hz to the favor of forward stimulation.Conclusions
Forward couplings, including direct stapes coupling, are mechanically superior to reverse stimulation. The stapes head coupler performs 7-25 dB better than the round window coupler and similar or even superior to incus couplers.
Various couplers exist for the Vibrant Soundbridge implant to connect the actuator to a middle ear structure. While the surgical indication mainly distinguishes between purely sensorineural hearing loss and mixed hearing loss, and audiological indication ranges are designed accordingly, we believe that the biomechanical distinction between forward and reverse cochlear stimulation is more meaningful. To evaluate this, we apply all common couplers in temporal bone experiments and correct the measurements for adequate comparability.Material And Methods
The study was conducted at two research labs, each with n = 10 cadaveric temporal bones. Laser Doppler velocity measurements on the stapes were used for direct comparison between the coupling methods. Therefore, reverse cochlear stimulation requires a correction factor due to pressure loss through a third window. This was calculated by measuring intracochlear pressure differences in the same specimens.Results
Compared to the stapes LDV measurement, reverse stimulations require a correction factor that continuously decreases in the high frequency range: approximately +22.4 dB between 125-250 Hz, +7.9 dB between 300-800 Hz, and +4.8 dB above 1000 Hz. Taking this into account, there is still a considerable difference between the forward and reverse stimulation methods of 15-22 dB in the frequency range <2000 Hz and approximately 7 dB >2000 Hz to the favor of forward stimulation.Conclusions
Forward couplings, including direct stapes coupling, are mechanically superior to reverse stimulation. The stapes head coupler performs 7-25 dB better than the round window coupler and similar or even superior to incus couplers.
Date Issued
2026-02
Publication Type
Article
Subjects
Couplers
•
Hearing implants
•
Reverse cochlear stimulation
•
Vibrant Soundbridge
Language(s)
en
Author(s)
Graf, Lukas | |
Stauske, David | |
Ghoncheh, Mohammad | |
Mojallal, Hamidreza | |
Stieger, Christof | |
Maier, Hannes |
Additional Credits
Journal
Hearing Research
Publisher
Elsevier
ISSN
1878-5891
0378-5955
Access(Rights)
open.access