COCHLEAR MECHANICS, WAVE PROPAGATION, AND COMPRESSION The proposed project continues a program of research that is improving our knowledge of cochlear function through a combination of theoretical and empirical studies of fundamental processes in the peripheral auditory system that have both basic and translational implications.
The first aim addresses a theoretical issue concerning power amplification in cochlear mechanics. It posits a mechanism for amplification in a four- chamber cochlear model and investigates consistency with experimental observations.
This aim tests supporting evidence for the existence of a hypothetical cochlear amplifier.
The second aim focuses on further development of a method for measurement of acoustic emissions from the inner ear that are evoked by wide- band noise stimuli. Signal processing and statistical analysis of these cochlear-reflectance measurements will improve their sensitivity to hearing loss and improve the accuracy of their prediction of hearing threshold. The remaining two aims of this project both utilize a cochlear-processing simulation, which is based on an existing nonlinear model of cochlear mechanics. Through a combination of computational modeling and behavioral measurements these aims will investigate two perceptual phenomena: consonant recognition and loudness growth.
These aims will both test the hypothesis that cochlear processing produces spectro-temporal features that are closer to observed perception than features derived directly from the acoustic signal. Through efforts related to all four aims, questions that possess both basic scientific interest and applied clinical relevance will be addressed by combined application of measurement and modeling efforts.

Public Health Relevance

The cochlea is the part of the inner ear that responds to sounds and is the primary organ for our sense of hearing. The proposed research program will develop a computational simulation of cochlear mechanics that addresses a fundamental question regarding amplification in the cochlea. In addition, results from cochlear models will be combined with physiological and behavioral data from human subjects to support the investigation of specific auditory phenomena, such as acoustic reflections from the cochlea, speech-consonant perception, and multi-tone loudness growth. Thus, the proposed research combines human measurements and computer simulations to address important questions about hearing processes that have both basic scientific and applied clinical relevance.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Study Section
Auditory System Study Section (AUD)
Program Officer
Cyr, Janet
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Father Flanagan's Boys' Home
Boys Town
United States
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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 :
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
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Groon, Katherine A; Rasetshwane, Daniel M; Kopun, Judy G et al. (2015) Air-leak effects on ear-canal acoustic absorbance. Ear Hear 36:155-63
Lewis, James D; Neely, Stephen T (2015) Non-invasive estimation of middle-ear input impedance and efficiency. J Acoust Soc Am 138:977-93

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