THE INFLUENCE OF MICROPHONE POSITION ON SOUND LOCALIZATION WITH HEARING AIDS

Van den Bogaert T, Carette E, Wouters J.

ExpORL, Dept. Neurosciences, K.U.Leuven, O&N2, Herestraat 49/721, B-3000 Leuven, Belgium.

The question whether hearing aids transmit enough cues for localizing sound sources and whether hearing aid users are able to use these cues to build up a realistic spatial auditory representation of our surrounding environment has recently gained a lot of interest. This is due to the wide application of bilateral hearing aid fittings, to the development of wirelessly inter-linked bilateral hearing aids, to the recent hearing aid designs enabling the preservation of binaural localization cues and to the flexible microphone configurations which aim at preserving the monaural spectral cues of the hearing aid user.

In this study hearing aid users, as well as normal hearing listeners as a reference, were evaluated in different localization experiments: elevation and front-back discrimination both focusing on the monaural spectral cues and left-right localization focusing on the binaural cues. The hearing impaired subjects were tested without and with different types of hearing aids with microphones behind-the-ear, in-the-canal and in-the-pinna.

Most of the hearing impaired subjects are capable of localizing sounds relatively accurate in all three dimensions (left-right / front-back / elevation) if the test procedure included a frequency specific audibility compensation for their hearing impairment. Differences between the different hearing aid designs were obtained. This difference was especially prominent in the front-back experiments.

[This research was partly funded by GN ReSound and the FWO - research foundation  Flanders – project G.0334.06N]

E-mail: jan.wouters@med.kuleuven.be