Psychoacoustics of normal and impaired hearing and applications to hearing aid design and fitting

In recent years many improvements have been made in the quality of hearing aids provided to hearing-impaired people. The majority of hearing-impaired people are now being fitted with digital hearing aids that offer great flexibility for tailoring the sound to best fit the residual hearing capacity of the person. However, even the best current hearing aids do not restore auditory perception to normal, and many users of hearing aids complain of difficulty in understanding speech, especially in noisy situations. Our goal is to make hearing aids work more effectively for hearing-impaired people, who constitute approximately 7% of the population in the UK. We also aim to develop ways of fitting hearing aids more effectively, so as to optimise the benefit to each individual.

Hearing impairment affects approximately 7% of the population in most developed countries, including the UK. In the majority of cases, the hearing loss is cochlear in origin, and cannot be ?cured?. The main form of treatment is via the use of hearing aids, and this is likely to remain the case for many years. Hearing aids can improve the audibility of soft sounds, but they are still of limited benefit in alleviating the major complaint of hearing-impaired people, which is difficulty in understanding speech in noise. This is true even for digital hearing aids, which are now available on the UK National Health Service, and which allow many possibilities for the processing of sound. One major goal of our research is to improve the effectiveness of hearing aids by: (1) the use of new and improved methods of signal processing in hearing aids; (2) development of improved methods of selecting the type of signal processing to be used with a particular individual; (3) development of improved methods for fitting hearing aids to an individual. All of these require an understanding of the basic processes and mechanisms that underlie the hearing loss, and that is also a focus of our work.