Age-related hearing loss is a highly prevalent chronic health condition that severely limits the older person’s ability to communicate during social, occupational, and other personal interactions and in turn, affects quality of life. Hearing aids are the principal form of remediation, but only 20% of elderly people with significant hearing loss obtain them. One of the primary reasons for limited use of hearing aids is that they do not provide sufficient benefit in noise or for understanding the speech of certain talkers, such as those who speak at a fast rate. This is due in part to age-related loss of signal audibility and reduced spectral resolution, and in part to age-related decline in speed of auditory processing.
The current project aims to address these two limitations of hearing aids through a systematic assessment of two types of signal processing algorithms that potentially can benefit older hearing-impaired listeners. One type of signal processing algorithm, developed by Dr. Espy-Wilson and her colleagues (Dept. of Electrical and Computer Engineering), seeks to separate the target speech signal from a competing speech signal at key intervals in the speech stream. The competing speech signal is then extracted and attenuated so that the total signal delivered to the hearing-impaired listener is primarily composed of the target speech message. The second type of signal processing algorithm, based on prior research by Dr. Gordon-Salant and her colleagues, attempts to slow certain brief segments of the speech signal (i.e., consonants) that are difficult for older hearing-impaired listeners to process, while at the same time attempts to accelerate relatively long segments of the speech signal (i.e., vowels and sonorants) that are highly redundant for older hearing-impaired listeners. A series of experiments are underway to assess the benefits of each of these signal processing algorithms for older hearing-impaired listeners. Ultimately, this highly innovative and collaborative program of research can dramatically alter the digital signal processing algorithm design of hearing aids to enhance speech understanding in realistic listening situations for elderly people, and thereby improve their quality of life.