Elderly listeners often experience poorer speech intelligibility than younger listeners, particularly in the presence of noise. Although an age- related reduction in hearing sensitivity likely contributes to this finding, recent scientific research suggests that an age-induced deficit in suprathreshold auditory processing may be present even in the absence of clinically significant hearing loss. Specifically, aging may result in a reduction in the cochlear nonlinearity which in turn may adversely affect suprathreshold processing. The cochlear nonlinearity, which is thought to reflect the functioning of the outer hair cells in the cochlea, is responsible for high sensitivity, sharp frequency tuning, and enhanced spectral contrasts via suppression. Thus, any reduction in the magnitude of the nonlinearity may result in one or more functional deficits, possibly including impaired speech intelligibility. The long-term goal of the proposed research is to further our understanding of the auditory processing of elderly listeners. In particular, this project will evaluate multiple psychophysical estimates of cochlear nonlinearity in young and aged listeners both with normal hearing and with mild- to-moderate hearing loss. For all proposed experiments, two different signal frequencies will be examined, one relatively low and one relatively high; these frequency regions may normally differ in their strength of nonlinear processing and thus differences between young and elderly listeners may be greater at the higher frequency. Thus, the purpose of this study is to examine multiple measures of cochlear nonlinearity in the same group of subjects to determine whether or not an age-related decline in the nonlinearity exists. The ultimate goal is to provide a better understanding of the listening difficulties experienced by elderly listeners.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31DC005085-01
Application #
6405031
Study Section
Communication Disorders Review Committee (CDRC)
Program Officer
Sklare, Dan
Project Start
2002-01-01
Project End
Budget Start
2002-01-01
Budget End
2002-12-31
Support Year
1
Fiscal Year
2001
Total Cost
$22,908
Indirect Cost
Name
Arizona State University-Tempe Campus
Department
Other Health Professions
Type
Schools of Arts and Sciences
DUNS #
188435911
City
Tempe
State
AZ
Country
United States
Zip Code
85287
Gifford, Rene H; Bacon, Sid P; Williams, Erica J (2007) An examination of speech recognition in a modulated background and of forward masking in younger and older listeners. J Speech Lang Hear Res 50:857-64
Gifford, Rene H; Bacon, Sid P (2005) Psychophysical estimates of nonlinear cochlear processing in younger and older listeners. J Acoust Soc Am 118:3823-33