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Auditory Signal Processing Laboratory

Our research is concerned with understanding how the human ear processes sound information, identifying hearing loss early and developing interventions for individuals with hearing loss.

  • ​​​​​​​Current Studies

    Noise Exposure and Hearing Problems Study

    We are seeking adults who have spent time in loud noise environments to participate in a ​research study to help us develop tests to identify hearing loss caused by loud noise exposure​. Research has shown that loud noise exposure can damage parts of the ear that respond to moderate and loud level sounds. This damage may cause problems with understanding speech in a background noise, such as in restaurants or at parties. The purpose of this research is to find ways to identify people who have hearing loss caused by loud noise exposure and eventually develop strategies for helping those people hear better in background noise.​

    Sign Up to Participate in this Study

    You can participate in this study if you are an English-speaking adult who has normal hearing or hearing loss and you have been exposed to gunfire, explosions or high impact noise or have difficulty understanding speech when there is other noise present.​

    Participants will be compensated for their time.​

    To learn more about this study, visit​. You may contact our lab by email ( or phone (531) 355-6373​.

    Sign Up to Participate in this Study​​​

  • ​​​Lab Overview

    The Auditory Signal Processing (ASP) Lab has two primary goals:​

    • Understanding suprathreshold hearing deficits and their relation to hidden hearing loss
    • Developing methods to identify hidden hearing loss in humans

    Hidden hearing loss is a form of hearing loss that cannot be diagnosed using current clinical procedures. Hidden hearing loss causes suprathreshold hearing deficits​ that include difficulty understanding speech in a background of noise. Our current experiments focus on determining the relationship between suprathreshold measures that are affected by hidden hearing loss and physiological measures of auditory function.

    The ASP Lab also aims to provide scientific basis for the need to restore cochlear processes that are diminished when hearing loss occurs, and to develop innovative signal-processing algorithms for hearing prostheses to restore these processes in individuals with hearing loss. Restoring these cochlear processes can improve speech perception, increase user satisfaction, and promote use of hearing technology, such as hearing aids. In order to provide the scientific basis needed, we first need to understand how the auditory system processes sound information. To this end, part of our research program focuses on use of noninvasive techniques to gain a better understanding of cochlear nonlinearity in humans with normal hearing and ​with hearing loss.


    This laboratory has a clinical audiometer used to determine threshold and a tympanometer used to assess middle-ear status. The laboratory includes two sound-treated booths and PCs for​ data-collection. The lab is also equipped with specialized hardware used for the measurement of electrophysiological responses, otoacoustic emissions, acoustic reflectance, speech perception and other psychoacoustic procedures. Custom-designed software for these measurements is installed in the PCs.


    The Auditory Signal Processing Lab is directed by Daniel M. Rasetshwane, Ph.D., and is supported by a grant from the National Institutes of Health, National Institute for Deafness and Communication Disorders (NIDCD) – grant number R03 DC013982. Judy G. Kopun, M.A. and Sara Fultz, Au.D., research audiologists, are in charge of laboratory operations. The lab benefits from internal collaborations with Stephen Neely, D.Sc.​, Michael Gorga, Ph.D.​, Walt Jesteadt, Ph.D.​ and ​Ryan McCreery, Ph.D. The lab be​nefits from external collaborations with Marc Brennan, Ph.D. at University of Nebraska, Lincoln and Odile Clavier, Ph.D. at ​Crear​​e Inc.

  • Specific Areas of Research

    1. Understand suprathreshold hearing deficits and their relation to hidden hearing loss
    2. Design and evaluation of audio signal-processing algorithms for hearing prostheses
    3. Use of loudness as a suprathreshold measure of cochlear function
    4. Furthering our understanding of reflectance and development of measurement techniques
    5. Impact of equipment and stimulus calibration on ear-canal measurements
    6. The origin and level-dependence of cochlear delays in human

    If you are interested in participating in a study, please contact Judy Kopun or Sara Fultz at (531) 355​-6373​ or