A new hearing aid variant. Preliminary evaluation.

An attempt was made to combine the advantages of a behind-the-ear (BTE) hearing aid (trouble-free use, powerful amplification, room for high-quality components, space for large energy source, use of extra equipment), with the advantages of the in-the-ear (ITE) hearing aid (improved intelligibility, improved directional hearing, improved signal/noise ratio). A BTE hearing aid was equipped with filters and provided with an external microphone. A first experiment, carried out in an anechoic chamber on KEMAR (Knowles Electronic Manikin for Acoustical Research), showed that directional variation of the frequency response of the hearing aid microphone was better in the new hearing aid than in the original BTE. A second experiment was carried out with a group of 6 normal-hearing persons concerning the frequency characteristic of sound transmission from twelve angles in the horizontal plane without a hearing aid, with a normal BTE aid, with the 'new aid', and with an ITE aid. The new instrument gave significantly better directional hearing than the original BTE aid. A clinical study will be started to verify and extend the experimental results obtained.