Date of Award

Spring 2013

Document Type

Dissertation

Degree Name

Doctor of Audiology (AuD)

Department

Department of Communication Sciences and Disorders

Advisor(s)

Christopher G. Clinard

Lincoln C. Gray

Brenda M. Ryals

Abstract

One of the most common complaints of persons with sensorineural hearing loss is difficulty hearing in background noise. Temporal fine structure (TFS) is one of the factors that contributes to understanding speech in the presence of background noise. TFS refers to the periodic information in speech which helps us to identify which speech sound we are listening to. TFS is also negatively affected by hearing loss, as well as age. In a quest to discover how TFS processing and thus speech-in-noise understanding can be improved, this study examined the effects of musical training on behavioral and physiological measures of temporal fine structure, as well as the brain-behavior relationship as it relates to frequency representation in the brainstem. This relationship was measured by two behavioral tests: frequency discrimination and a measure of speech understanding in background noise – the Hearing-in-Noise test (HINT), and one physiologic measure, the frequency following response (FFR). The stimuli for frequency discrimination and the FFR were tonebursts of 500 Hz in quiet, 1000 Hz in quiet, 500 Hz in noise, and 1000 Hz in noise. A total of 28 subjects were tested, 16 musicians and 12 non-musicians. The results showed that musicians had better frequency difference limens (FDLs) than non-musicians. For the physiologic measure, musical experience did not affect phase-locked representations of TFS. Musicians also did not have better signal-to-noise ratios on the HINT. There were no significant brain-behavior relationships between measures except that lower or better FDL thresholds at 1000 Hz in quiet implied lower or worse phase coherence at 1000 Hz in quiet. A greater number of years of musical experience related to lower or better FDLs for the conditions in quiet but not in noise. The years of training did not relate to performance on FFR phase coherence, amplitude, or HINT scores. It was concluded that musical training significantly enhanced behavioral TFS processing, however no significant effects were noted for neural representation of TFS or speech-in-noise understanding.

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