Skull simulator for direct bone conduction hearing devices.

The Bone-Anchored Hearing Aid (BAHA) is a direct bone conduction hearing device which has given patients with various middle ear disorders a significantly improved quality of life. As the BAHA has gained acceptance as a valuable contribution to the Swedish hearing aid rehabilitation program, the need for equipment which can perform objective frequency response measurements has grown. Such equipment is indispensable for carrying out quality assurance, service, and fitting evaluation. To meet the above-mentioned demands, the skull simulator TU-1000 has been developed. The dynamic behaviour of the skull simulator TU-1000 can be characterized as that of a rigid mass body with a weight significantly exceeding the weight corresponding to the dynamic mass of the transducer incorporated in the BAHA. The motions of the mass body are measured by an accelerometer the output signal of which is amplified by a precalibrated amplifier. The output signal is proportional to the output force level from the BAHA. The skull simulator TU-1000 is capable of measuring the output force level from the BAHA with high reliability for frequencies ranging from 100 Hz to 10 kHz.