Hearing-aid users’ voices: A factor that could affect directional benefit

Abstract

Objective: Backward-facing directional processing (Back-DIR) is an algorithm that employs an anti-cardioid directivity pattern to enhance speech arriving from behind the listener. An experiment that was originally designed to evaluate Back-DIR, together with its follow-up experiment, are reported to illustrate how hearing-aid users’ voices could affect directional benefit. Design: Speech recognition performance was measured in a speech-180°/noise-0° configuration, with aids programmed to Back-DIR enabled or omnidirectional processing. In the original experiment, the conventional hearing-in-noise test (HINT) was used, wherein listeners repeated heard sentences. In the follow-up experiment, a modified HINT was used, wherein a carrier phrase was presented before each sentence. Study sample: Fifteen adults with sensorineural hearing loss participated in both experiments. Results: Significant Back-DIR benefit (relative to omnidirectional processing) was observed in the follow-up experiment, while not in the original experiment. Conclusions: In the original experiment, hearing aids were affected by listeners’ voices such that Back-DIR was not always activated when the target speech was presented. In the follow-up experiment, listeners’ voice effects were eliminated by the carrier phrase activating Back-DIR before the sentences were presented. The results suggest that the effect of hearing-aid technologies is highly dependent on the characteristics of listening conditions.

Key Words::

• Hearing aid
• directional microphone
• voice

Acknowledgements

The authors thank Dr. Sepp Chalupper for his contributions in research design. Portions of this paper were presented at the annual meeting of the American Auditory Society, March 10th, 2012, Scottsdale, Arizona, USA.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This research was supported by a research grant from Siemens Hearing Instruments, Inc.