The purpose of this project is to determine the nature of the hearing difficulties experienced by listeners whose ability to hear quiet sounds like pure tones is still relatively good. One particular focus of the project is on older listeners who, despte normal audiograms, find understanding speech in background sounds difficult. For comparison, younger listeners with cochlear hearing loss will also be examined. The framework of the project is structured around 3 Specific Aims.
The first Aim explores the possibility that normal thresholds in quiet can belie permanent neural dysfunction at the level of the auditory nerve, a situation that parallels noise exposure work showing that recovery of sensitivity following acoustic over-exposure can occur despite residual nerve damage.
This Aim will lead to a better delineation of the sound-processing deficits that exist in the face of apparently good hearing.
The second Aim focuses on auditory brainstem responses [ABRs] evoked by complex sounds like speech. This type of ABR testing is rapidly growing in usage but much remains to be understood about the basic response. The immediate goal of the second Aim is to study the particular situation of age-related differences in the speech-evoked ABR, but the broader objective is to use this study as a vehicle to better understand the multiplicity of factors that contribute to the generation of the speech-evoked ABR both in the normal and cochlear-impaired auditory system.
The final Aim contributes a new perspective on factors that affect speech understanding in everyday listening environments where the background sound is typically fluctuating in both time and frequency making the glimpses of target speech themselves dynamically vary across these dimensions as well as across ears. Together, these three Aims combine to provide a series of parallel studies that will significantly advance our understanding of the processing of complex sounds like speech in challenging listening environments, even for people with relatively good hearing.

Public Health Relevance

of this project to public health is that it advances our understanding of everyday listening difficulties experienced by people with hearing loss, as well as by people whose hearing is otherwise deemed to be good - especially those who are older. The project also provides new insights into objective tests of hearing that are gaining in popularity. Overall, the findings will be relevant to the public health challenge of the burgeoning communication difficulties experienced by an increasingly aging population.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC001507-21
Application #
8677864
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Donahue, Amy
Project Start
1992-12-01
Project End
2018-08-31
Budget Start
2014-09-01
Budget End
2015-08-31
Support Year
21
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Grose, John H; Porter, Heather L; Buss, Emily et al. (2016) Cochlear hearing loss and the detection of sinusoidal versus random amplitude modulation. J Acoust Soc Am 140:EL184
Grose, John H; Menezes, Denise C; Porter, Heather L et al. (2016) Masking Period Patterns and Forward Masking for Speech-Shaped Noise: Age-Related Effects. Ear Hear 37:48-54
Mamo, Sara K; Grose, John H; Buss, Emily (2016) Speech-evoked ABR: Effects of age and simulated neural temporal jitter. Hear Res 333:201-9
Grose, John H; Mamo, Sara K; Buss, Emily et al. (2015) Temporal Processing Deficits in Middle Age. Am J Audiol 24:91-3
Grose, John H; Griz, Silvana; Pacífico, Fernando A et al. (2015) Modulation masking release using the Brazilian-Portuguese HINT: psychometric functions and the effect of speech time compression. Int J Audiol 54:274-81
Grose, John H; Buss, Emily; Porter, Heather L et al. (2013) Across-frequency envelope correlation discrimination and masked signal detection. J Acoust Soc Am 134:1205-14
Grose, John H; Mamo, Sara K (2012) Frequency modulation detection as a measure of temporal processing: age-related monaural and binaural effects. Hear Res 294:49-54
Grose, John H; Mamo, Sara K (2012) Electrophysiological measurement of binaural beats: effects of primary tone frequency and observer age. Ear Hear 33:187-94
Grose, John H; Buss, Emily; Hall 3rd, Joseph W (2012) Binaural beat salience. Hear Res 285:40-5
Grose, John H; Mamo, Sara K (2010) Processing of temporal fine structure as a function of age. Ear Hear 31:755-60

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