A review of current "noise reduction" hearing aids: rationale, assumptions, and efficacy.

Amplification technology has changed considerably in the last decade, particularly with the introduction of more advanced adaptive signal processing approaches and digital/hybrid hearing aids. Because difficulty understanding speech in the presence of background noise is the most common complaint of hearing-impaired patients, an increasing number of these new products are being marketed as "noise reduction" hearing aids. There reamin, however, many unanswered questions regarding patient candidacy for these instruments, and the relative benefit that can be expected from the new technology. This article discusses issues and assumptions underlying noise reduction strategies, reviews categories of hearing aids on the market that are meant to alleviate listening difficulty in noise, and outlines future needs in research and development in this area.