Hearing Thresholds with Direct Bone Conduction Versus Conventional Bone Conduction

TLDR

Patients needing bone‑conduction hearing aids often suffer discomfort from transducer pressure and poor electroacoustic performance due to skin attenuation. The study aims to compare hearing thresholds in 10 patients using a bone‑anchored hearing aid with permanent skin penetration versus conventional bone‑conduction. Ten patients were fitted with the bone‑anchored aid and underwent Békésy audiometry using a conventional Oticon A‑type transducer. Skin penetration lowered hearing thresholds by 10–20 dB between 600 and 6000 Hz, reducing transducer distortion, electrical gain, and power consumption.

Abstract

Some patients who need hearing aids are unable to use an aid which transmits the sound via the external ear canal, but have to use a bone-conduction hearing aid. The pressure needed to apply the transducer often gives the patient discomfort, and the attenuating effect of the skin gives poor electroacoustical function of the aid. A permanent skin penetration has made it possible to develop a boneanchored hearing aid with all components in one housing. Ten patients have been equipped with such an aid. This paper deals with a comparative hearing threshold measurement on 10 patients. Békésy audiometry was performed and a conventional Oticon (A-type) transducer was used. In the frequency range 600 to 6000 Hz, there was a lowering of 10–20 dB in thresholds when skin penetration was performed. This lowering in thresholds means lower transducer distortion, lower electrical gain, and lower power consumption to produce a given sensation level.