Current Research Projects

Choosing the best amplification parameters for listeners with severe hearing loss

Wide dynamic range compression (WDRC) hearing aids are intended to improve speech recognition by using rapid, automatic gain adjustments to place more speech information within the listener’s audible range. About 90% of hearing aids now offer WDRC processing, so over time this technology will be provided to most of the 6.2 million hearing aid wearers in the United States. Because of their broadened auditory filters and poor spectral resolution, severely-impaired listeners rely to a greater extent on temporal information including variations in speech amplitude both within and across phonemes—information that is distorted by WDRC processing. The goal of this research is to describe speech recognition in listeners with severe hearing loss and to determine an acceptable range of amplification parameters that will optimize speech recognition for these listeners.

Understanding the effects of current amplification strategies on the acoustic cues needed to recognize speech

Current hearing aids use a variety of strategies to process speech and reduce amplification of background noise. In this series of projects, we address several aspects of hearing aid processing. One is exploring how increasing numbers of compression channels alter spectral cues. Another is acoustic analysis of the effects of hearing aid expansion on consonant audibility and amplitude envelope. In collaboration with other department faculty, we are exploring use of electrophysiological recordings to measure the response to amplified speech at the cortex. The overall goal of this research is to understand the effects of amplification on the essential acoustic cues for speech recognition.

Determining the best way to provide hearing aid training and follow-up

Technology alone does not create a successful hearing aid wearer. The listener’s understanding of the device, ability to use the hearing aid to maximum advantage, and motivation to adjust to the new sound are important. In this study, in collaboration with researchers at the Seattle Veteran’s Administration, we will compare the cost effectiveness and benefits for patients of either a group or individual hearing aid orientation, in combination with a group or individual hearing aid follow-up.

Support

We are grateful to the following sources for support: National Institute of Deafness and Communication Disorders; Virginia Merrill Bloedel Hearing Research Center; Rehabilitation Research and Development Service of the Department of Veteran’s Affairs; and the University of Washington Technology Gap Innovation Fund.

We frequently need volunteers interested in trying out new hearing aid technologies. If you are interested in learning more or participating in our research, please contact us at hearlab@u.washington.edu.