Objectives
The audiological results after implantation of the Vibrant Soundbridge (VSB) often show a range of variation in the clinical setting. At the edge of the indication, precise knowledge of the influencing factors is necessary to achieve satisfactory speech intelligibility. Floating mass transducer (FMT) coupling is an important factor. Therefore, data from human temporal bone (TB) experiments were compared to the postoperative hearing outcome after VSB implantation. Coupling structures included the long (LP coupler) and short (SP coupler) incus processes, the stapes head (Clip coupler) and the round window membrane (RW soft coupler).
Methods
Transmission after vibroplasty was measured in 32 temporal bones using laser Doppler vibrometry on the stapes footplate. Audiometric data of 69 patients were analysed 6 months after VSB implantation. The following outcome parameters were compared: postoperative aided speech intelligibility at 65 dB, mean pre- and postoperative bone conduction hearing thresholds, free field aided threshold, coupling efficiency and effective gain (500 to 4000 Hz.
Results
In the experiments, the LP coupler tended to have the best coupling quality in the low frequencies (500 to 1000 Hz) of the main speech range (500 - 4000 Hz). This was up to 15 dB better than the worst coupling mode (RW soft coupler). In the high frequencies (2000 to 4000 Hz) the Clip coupler displayed the best coupling quality. This was 15 dB above the worst coupling mode (SP coupler).
Postoperative speech intelligibility, averaged free field threshold and coupling efficiency displayed no significant differences between the coupling modes. The inferiority of the RW soft coupler in the low-frequency range and the superiority of the Clip coupler in the high-frequency range, as known from experimental studies, were confirmed. However, the clinical results did not reach significance (p>0.05).
Conclusion
No significant differences in speech intelligibility in vivo were revealed when the coupling structures were compared. The differences found in the experimental studies were suppressed by individual confounding factors. However, when considering VSB implantation, the frequency-dependent differences between the different coupling modes should be taken into account in order to achieve satisfactory speech intelligibility.

Influence of the coupling on the hearing outcome after Vibrant Soundbridge implantation: comparison of the transmission in temporal bone experiments with clinical data

It is with great pleasure and enthusiasm, that on behalf of the Cochlear Implant centers of the Radboud UMC in Nijmegen and Erasmus MC Sophia Children’s Hospital in Rotterdam to invite you to attend the 16th European Symposium on Pediatric Cochlear Implantation to Rotterdam, the Netherlands in 2023.

Yours sincerely, on behalf of the CI Centers at Radboud UMC and Erasmus MC,