Comparison of wireless and acoustic hearing aid-based telephone listening strategies

The purpose of this study was to examine speech recognition through hearing aids for seven telephone listening conditions.

Speech recognition scores were measured for 20 participants in six wireless routing transmission conditions and one acoustic telephone condition. In the wireless conditions, the speech signal was delivered to both ears simultaneously (bilateral speech) or to one ear (unilateral speech). The effect of changing the noise level in the nontest ear during unilateral conditions was also examined. Participants were fitted with hearing aids using both nonoccluding and occluding dome ear tips. Participants were seated in a room with background noise present and speech was transmitted to the participants without additional noise.

There was no effect of changing the noise level in the nontest ear and no difference between unilateral wireless routing and acoustic telephone listening. For wireless transmission, bilateral presentation resulted in significantly better speech recognition than unilateral presentation. Bilateral wireless conditions allowed for significantly better recognition than the acoustic telephone condition for participants fitted with occluding ear tips only.

Routing the signal to both hearing aids resulted in significantly better speech recognition than unilateral signal routing. Wireless signal routing was shown to be beneficial compared with acoustic telephone listening and in some conditions resulted in the best performance of all of the listening conditions evaluated. However, this advantage was only evident when the signal was routed to both ears and when hearing aid wearers were fitted with occluding domes. Therefore, it is expected that the benefits of this new wireless streaming technology over existing telephone coupling methods will be most evident clinically in hearing aid wearers who require more limited venting than is typically used in open canal fittings.