Current Research Projects

The aim of this project is to develop and evaluate signal processing schemes that enable users of hearing aids to train their devices to their preferred characteristics in varying everyday listening situations.

To date a trainable hearing aid concept (Dillon et al., 2006) has been successfully developed, implemented, and evaluated (Zakis et al., 2007). The first version of a trainable hearing aid trained the static characteristic (gain below the compression threshold, compression ratio, and noise suppression strength) in three frequency bands using information about simple measures of the acoustic input (intensity level and estimated signal-to-noise ratio) and self-adjustments of gain. Out of thirteen hearing aid users who spent one to four weeks training the test device, nine showed a significant preference for their trained response over the NAL-NL1 prescribed response at the conclusion of a comparison trial that was conducted double blinded. Other aspects of trainability have been explored, including potential users of trainability (Keidser et al., 2007), the effect of using different control configurations (Dreschler et al., 2008), and the effect of baseline response (Keidser et al., 2008). These studies have suggested that while hearing aid candidates like the idea of performing self-adjustments of gain in their own environments, most would want the training to be completed within a few weeks with the use of no more than two controls. Interestingly, the use of different control configurations did not affect the end result; however, the baseline response did, suggesting that self-adjustments, and fine-tuning of gain, should be performed from an adequate starting response.

A new algorithm is currently being implemented in a real-time system for evaluation in the field.

A test participant is adjusting the amplification characteristic using a simple control configuration while listening to traffic noise

References:

1. Dillon H, Zakis J, McDermott H, Keidser G, Dreschler W and Convery E (2006). The trainable hearing aid: What will it do for clients and clinicians? Hearing Journal, 59:30-36.

2. Dreschler WA, Keidser G, Convery E and Dillon H (2008). Client-based adjustments of hearing-aid gain: the effect of different control configurations. Ear and Hearing, 29(2):214-227.

3. Keidser G, Convery E and Dillon H (2007). Potential users and perception of a self-adjustable and trainable hearing aid: A consumer survey. Hearing Review, 14(4): 8-20,24,26,31.

4. Keidser G, Convery E and Dillon H (2008). The effect of a self-adjustable and trainable hearing aid: A consumer survey. Journal of the Acoustical Society of America 124(3), 1668-1681.

5. Zakis JA, McDermott HJ and Dillon H (2007). The design and evaluation of a hearing aid with trainable amplification parameters. Ear and hearing, 28(6):812-830.