This research program focuses on theoretical and empirical studies that address current issues in cochlear mechanics relevant to noninvasive evaluation of cochlear function. The major objectives of these studies are to understand cochlear-wave propagation and to characterize cochlear compression. These objectives are approached through six specific aims. The first three aims focus on aspects of cochlear-wave propagation through modeling efforts directed at the following theoretical issues: (1) appropriate characterization of cochlear-amplifier gain;(2) a more complete understanding of distortion-product retrograde wave propagation;and (3) understanding the mechanisms that underlie notches in basilar-membrane measurements. The next three aims characterize cochlear compression growth through a combination of empirical studies involving human subjects and theoretical work involving models of cochlear mechanics. Specifically, these three studies are designed to increase our understanding of the relation between: (4) compression growth rate (CGR) and the slope of forward-masking psychometric functions;(5) CGR and suppression growth rate;and (6) CGR and cochlear reflectance. The modeling work will facilitate interpretation of the measurements and provide a deeper understanding of cochlear wave-propagation, cochlear compression, and negative damping regions. Reliable estimation of CGR is clinically significant for the remediation of hearing loss because its deviation from normal provides a precise estimate of the amount of compression that an external hearing aid needs to provide. The goal of the proposed research is the development of a computational model of cochlear mechanics that will facilitate the interpretation of noninvasive measures of peripheral auditory status in humans. This work is relevant to public-health because people with hearing loss not only have problems hearing soft sounds, they also experience sounds growing louder too quickly. Understanding how the sense organ of hearing (the cochlea) influences the growth of loudness should provide useful information for the design of hearing aids tailored to individual needs.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Special Emphasis Panel (ZRG1-IFCN-B (02))
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Donahue, Amy
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Father Flanagan's Boys' Home
Boys Town
United States
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Ridley, Courtney L; Kopun, Judy G; Neely, Stephen T et al. (2018) Using Thresholds in Noise to Identify Hidden Hearing Loss in Humans. Ear Hear 39:829-844
Siegel, Jonathan H; Nørgaard, Kren Rahbek; Neely, Stephen T (2018) Evanescent waves in simulated ear canals: Experimental demonstration and method for compensation. J Acoust Soc Am 144:2135
Nørgaard, Kren Rahbek; Neely, Stephen T; Rasetshwane, Daniel M (2018) Quantifying undesired parallel components in Thévenin-equivalent acoustic source parameters. J Acoust Soc Am 143:1491
Neely, Stephen T; Fultz, Sara E; Kopun, Judy G et al. (2018) Cochlear Reflectance and Otoacoustic Emission Predictions of Hearing Loss. Ear Hear :
Trevino, Andrea C; Jesteadt, Walt; Neely, Stephen T (2016) Development of a multi-category psychometric function to model categorical loudness measurements. J Acoust Soc Am 140:2571
Sieck, Nicole E; Rasetshwane, Daniel M; Kopun, Judy G et al. (2016) Multi-tone suppression of distortion-product otoacoustic emissions in humans. J Acoust Soc Am 139:2299
Trevino, Andrea C; Jesteadt, Walt; Neely, Stephen T (2016) Modeling the Individual Variability of Loudness Perception with a Multi-Category Psychometric Function. Adv Exp Med Biol 894:155-164
Rasetshwane, Daniel M; Fultz, Sara E; Kopun, Judy G et al. (2015) Reliability and clinical test performance of cochlear reflectance. Ear Hear 36:111-24
Rasetshwane, Daniel M; Neely, Stephen T (2015) Reflectance measurement validation using acoustic horns. J Acoust Soc Am 138:2246-55
Lewis, James D; Kopun, Judy; Neely, Stephen T et al. (2015) Tone-burst auditory brainstem response wave V latencies in normal-hearing and hearing-impaired ears. J Acoust Soc Am 138:3210-9

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