Comparison of Thresholds Obtained With the Radioear B-71 and B-81 Bone-Conduction Transducers.

Abstract

A new bone conduction transducer, the Radioear B-81, has been designed to be an improvement over the commonly used transducer, the Radioear B-71. Reference Equivalent Threshold Force Levels (RETFLs) were obtained with the new Radioear B-81. Thresholds were obtained in accordance with ANSI-S3.6-2018 (Annex D) and participants were selected as prescribed in ISO 389.9-2009. Thresholds were obtained with automatic audiometry using circumaural earphones (Radioear DD450) and forehead placement of the bone vibrators. Mean bone conduction thresholds obtained using the B-81 and B-71 bone oscillators for frequencies from 250 to 4000 Hz were not statistically different. RETFLs for the B-81 are identical to the values in ANSI S3.6-2018 for the B-71 bone vibrator. Air-bone gaps were observed for both transducers at low frequencies (250 and 500 Hz) due to occlusion effects produced by the circumaural earphone and at high frequencies (3000 and 4000 Hz), previously reported in several studies that used standard RETFLs. Test-retest differences for air conduction thresholds were analyzed and the results are presented in the Appendix A (Supplemental Digital Content 1, http://links.lww.com/EANDH/A639). RETFLs in ANSI S3.6-2018 and ISO 389.3-2016 are appropriate for use with the B-81 bone vibrator.