Abstract:
Air versus bone conduction loudness balance testing was performed at the frequencies 0.25, 0.5, 0.75, 1, 2, and 4 kHz in three groups of subjects: normal-hearing subjects, subjects with pure sensorineural hearing loss, and subjects with mixed hearing loss. The subjects were fitted with earphones (Koss portaPro) and a percutaneous bone transducer (HC-380) or an audiometric transducer (B71). Narrow-band noise was presented interchangeably between the earphones and the bone transducer. Balance testing was performed at each frequency and at different levels (30--80 dB HL in 10-dB steps) in the following manner: The sound pressure from the earphones was fixed and the subject under test adjusted the output level from the bone transducer for equal loudness similar to the procedure used in the conventional ABLB test. Preliminary results and their interpretation will be presented.