Audibility of the Bone Conduction Device Headband Trial in Single-sided Deaf Subjects.

Data and Code of the study Objective<br> This study aims to evaluate if a transcutaneous Bone Conduction Device (BCD), attached to the headband, can adequately compensate for the head shadow effect, providing subjects with Single-Sided Deafness (SSD) with a balanced CROS-fitting. Participants<br> Eighty-five adults with SSD, enrolled in a Randomized Controlled Trial, were fitted during a trial period with a transcutaneous Bone Conduction Device (BCD). Method<br> After loading the first-fit settings, the BCD output was measured on a skull-simulator. The sensation levels of the Bone-Conduction and Air-Conduction sound paths were compared, simulating three different spatial conditions with speech in quiet, with the signal in front of the subject, at BCD-side, and on the best-ear side respectively. We modeled the speech perception with aid of the Speech Intelligibility Index and the CVC-score for those conditions and, additionally, for seven conditions with speech in noise: 1. With signal and noise directly in front of the subject; 2. With the signal in front and the noise from the BCD-side; 3. With the signal in front and the noise from the best-ear-side; 4. With the signal from the BCD-side and the noise from the best-ear-side; 5. With the signal from the BCD-side and the noise in front; 6. With the signal from the best-ear-side and the noise from the BCD-side; 7. With the signal from the best-ear-side and the noise in front. Results<br> We could retrieve data about 49 fittings with a Cochlear^TM BP110 and 36 fittings with a Cochlear^TM BAHA^® 5 Power (BAHA5P) on a headband. Due to some missing BC-direct thresholds, we present complete data of 35 subjects fitted with a BP110 and 35 subjects fitted with a BAHA5P.<br> The BAHA5P delivered higher output force levels in the high-frequency range compared to the BP110. However, neither the BP110 nor the BAHA5P could provide the large majority of the subjects with SSD and (near) normal hearing in the best ear with a balanced CROS-effect. With first-fit settings, only 9% of individuals of our population achieved an audible CROS-effect in the most favorable condition, with the signal at the BCD-side. In the condition with the signal in front of the subject, the number of fittings with an audible CROS-effect drops to 0. The transcutaneous BCD did not provide any substantial positive effect on the speech understanding, during the three simulated listening situations in quiet. In noise, we found a limited improvement in some specific conditions and a very small degradation in others. Analysis of the logbook showed a low daily usage of the transcutaneous BCD. Conclusion<br> This study challenges the evidence-based fundamentals of a trial period with a transcutaneous BCD in subjects with SSD. Even with current “power” BCDs, it is not possible to achieve a satisfactory audibility of speech during the headband trial in the large majority of subjects with SSD and (near) normal hearing in the best ear. Further research has to highlight if a wireless (Bi)CROS-system can provide SSD-subjects with a reliable trial period to assess the possible benefits of head shadow effect compensation in daily life.