Table of Contents

ABSTRACT

For a large proportion of people with hearing loss, understanding speech in noisy listening environments can be very challenging. To overcome the problem, many modern hearing aids incorporate noise reduction features or techniques to reduce the background noise or enhance the signal-to-noise ratios (SNRs). Among the common noise reduction features are digital noise reduction (DNR), directional microphones (DIR), expansion, transient noise reduction (TNR), and wind noise reduction. In this paper, the concept of each noise reduction feature, and how it works with the background noise are covered as intended. The benefits and effects of various noise reduction features on speech understanding and listening comfort among hearing aid users are discussed based on previous studies. Limitations of the noise reduction techniques to improve speech intelligibility and research implications are also explained. In conclusion, most noise reduction features have positive effects on improving listening comfort in noise. The DIR relatively to other noise reduction strategies, seems to be the most effective feature in improving the SNRs. Nevertheless, more research evidence is needed to understand the benefits of applying noise reduction features on hearing aids used by children with hearing loss.

Keywords: Hearing loss, hearing aid, speech intelligibility, noise reduction, directional microphone