Better Understanding of Direct Bone-Conduction Measurement:Comparison with Frequency-Specific Bone-Conduction Tonesand Brainstem Responses

ABSTRACT

The present study aimed to compare thresholds of directbone-conduction (BC direct) with those of behaviorally measured BC pure-tone audiometry(PTA) and objectively measured BC auditory brainstem response (ABR) to confirm the clinicalfeasibility of their relationships. Subjects and Methods: Young adults with normal hearingparticipated in the study to determine the thresholds from three measurements at four testingfrequencies. In the BC direct, the vibrator of a bone-anchored hearing aid softband wasplaced on the right mastoid of each subject. In both PTA and ABR, a B71 bone oscillatorwas placed on the subject’s right mastoid. While the subject’s thresholds of BC direct andBC PTA were determined with a clinically routine 5-dB step procedure, BC ABR was conductedto determine the individual’s hearing sensitivity by a peak V of the waveform usingtone-burst and click stimuli. Results: The BC direct showed a different pattern between lowand high frequencies. Precisely, its thresholds were 13.25 and 12.25 dB HL at 0.5 and 1kHz, respectively, but 19 and 19.75 dB HL at 2 and 4 kHz, respectively. A significant positivecorrelation existed between BC direct and PTA at 1 kHz, which was also correlated withABR. Conclusions: Based on the current data, the thresholds of BC direct were similar toBC PTA at low frequencies and BC ABR at high frequencies. The thresholds of BC directmight be predictable at approximately 5 dB higher (or lower) than that in PTA, although alarge data set is required for standardization. J Audiol Otol 2020;24(2)85-90