Objectives: The VIBRANT SOUNDBRIDGE is a widely used active middle ear implant to treat hearing loss. The floating mass transducer is surgically coupled to the ossicles, the round or oval window. A reliable method to monitor the coupling efficiency intraoperatively is highly desired. Research groups have developed several methods, but limitations remain. This study aims to evaluate the clinical feasibility of a new research setup for auditory brainstem response measurement to evaluate the coupling efficiency.
Method: In 14 subjects, the new tool was used to record VSB-evoked ABR thresholds during surgery. The intra-op ABR thresholds were compared to pre-op bone conduction (BC) thresholds and post-op vibrogram thresholds to evaluate the feasibility of the method as a tool to monitor coupling efficiency.
Results: The mean pre-op BC threshold average at 1, 2, and 4 kHz (PTA3) was 47 dB HL, the mean intra-op ABR threshold was 54 dB nHL, and the mean post-op vibrogram PTA3 was 60 dB HLeq. ABR was measurable in all subjects using the new tool. Correlation between pre-op BC thresholds and intra-op ABR thresholds was statistically significant; however, one outlier was present.
Conclusion: Intra-op hearing threshold detection through ABR and direct stimulation of the VSB implant was reliable using this new tool. Despite some individual variability, first results correlate well with pre-op BC and post-op vibrogram thresholds.