The long-term goal of the proposed work is to improve our understanding of the neural representation of speech in the presence of sensorineural hearing loss. Single neuron recordings will be made in cats exposed to intense noise, which produces a hearing loss comparable to moderate high frequency loss (greater than or equal to 1 kHz).
The first aim i s designed to test and further develop a way of compensating for the loss of sharp cochlear tuning and nonlinear suppression in damaged cochleas.
The aim i s to develop a method of specifying the optimum spectral shape for presenting a particular speech sound to an ear with a particular hearing loss, where optimum means designed to produce patterns of auditory nerve activity that are as normal as possible.
The second aim will characterize neural responses to running speech, instead of the isolated phonemes that are usually used in auditory experiments. The representation of sentence-level speech will be characterized in both the spectral and temporal domains, for both normal and damaged ears. The compensation methods developed in the first aim will be tested using these stimuli. The effects of background noise will also be examined. In the third aim, an accurate computational model of auditory nerve activity in a damaged ear will be developed. Development and testing of the model will be closely coordinated with the experimental studies of the first two aims. The goal is to produce a model which is accurate enough to be used as a test bed for developing hearing-aid signal- processing.
The final aim will study how cats with a hearing loss discriminate variants of the vowel /epsilon/ with different second formant frequencies. These behavioral experiments are designed to differentiate between two models of information representation in the auditory nerve, the so-called rate-place, and temporal-place models. The experiments take advantage of the fact that cats with a moderate hearing loss do not have rate-place information which would allow them to discriminate these vowels.
This aim will provide evidence, for the first time, on the relative importance of the two information representation codes in the auditory nerve and will be important in interpreting the results of the experiments in the other three aims.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Hearing Research Study Section (HAR)
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Johns Hopkins University
Biomedical Engineering
Schools of Medicine
United States
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Ropp, Tessa-Jonne F; Tiedemann, Kerrie L; Young, Eric D et al. (2014) Effects of unilateral acoustic trauma on tinnitus-related spontaneous activity in the inferior colliculus. J Assoc Res Otolaryngol 15:1007-22
Paninski, Liam; Ahmadian, Yashar; Ferreira, Daniel Gil et al. (2010) A new look at state-space models for neural data. J Comput Neurosci 29:107-26
May, Bradford J; Little, Nicole; Saylor, Stephanie (2009) Loudness perception in the domestic cat: reaction time estimates of equal loudness contours and recruitment effects. J Assoc Res Otolaryngol 10:295-308
Young, Eric D (2008) Neural representation of spectral and temporal information in speech. Philos Trans R Soc Lond B Biol Sci 363:923-45
Ma, Wei-Li Diana; Young, Eric D (2006) Dorsal cochlear nucleus response properties following acoustic trauma: response maps and spontaneous activity. Hear Res 216-217:176-88
Heinz, Michael G; Issa, John B; Young, Eric D (2005) Auditory-nerve rate responses are inconsistent with common hypotheses for the neural correlates of loudness recruitment. J Assoc Res Otolaryngol 6:91-105
Heinz, Michael G; Young, Eric D (2004) Response growth with sound level in auditory-nerve fibers after noise-induced hearing loss. J Neurophysiol 91:784-95
Ngan, E M; May, B J (2001) Relationship between the auditory brainstem response and auditory nerve thresholds in cats with hearing loss. Hear Res 156:44-52
May, B J; Prell, G S; Sachs, M B (1998) Vowel representations in the ventral cochlear nucleus of the cat: effects of level, background noise, and behavioral state. J Neurophysiol 79:1755-67
Hienz, R D; Stiles, P; May, B J (1998) Effects of bilateral olivocochlear lesions on vowel formant discrimination in cats. Hear Res 116:10-20