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.
