Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Spring 2017

Document Type


Degree Name

Doctor of Audiology (AuD)


Department of Communication Sciences and Disorders


Christopher G. Clinard

Lincoln C. Gray

Brenda M. Ryals


The purpose of the present study was to examine why older adults have trouble with speech-in-noise understanding. Difficulty with speech-in-noise comprehension has been associated with age-related degradation in frequency processing. Our study sought to investigate this relationship by examining the neural representation of frequency in quiet and in noise across the adult-life span. In order to do this, one behavioral correlate of frequency processing, frequency difference limens (FDLs), and one electrophysiological correlate, the frequency following response (FFR), was utilized. In the present study, we specifically focus on the electrophysiological measures of frequency processing across the adult life span. It was hypothesized that as age increased, FFR phase coherence and FFR amplitude would decrease (i.e. neural synchrony was expected to degrade with age). It was also hypothesized that masking noise would be expected to have an adverse effect on both FFR phase coherence and amplitude, with older adults having more adverse effects than the younger adults.

Properly identifying the underlying source(s) of impairment is essential to designing appropriate treatment plans that effectively target these underlying deficits. Thus, the present study aims to determine how frequency processing is affected by aging and what consequences it may have on speech-in-noise understanding in older adults.



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