Sound evaluation of partially implantable piezoelectric middle ear implant: comparative study of frequency responses

Two comparative studies were performed in six subjects using partially implantable middle ear implants (MEI). The sound quality was evaluated by speech discrimination tests and sound evaluation tests. In the first experiment, the performance of the output transducer of the MEI and an ear phone of a conventional hearing aid was compared. The MEI showed better results than the hearing aid in both the speech discrimination tests and sound quality rating. In the second experiment, four kinds of frequency responses for the external component of the MEI were compared. Sound quality evaluation in a wide frequency response with a peak at 4000 Hz were superior to those with the frequency response of the present MEI model. In conclusion, improvement of the external component in the frequency response can provide better performance of the MEI.