Efferent-mediated changes in the composite distortion product otoacoustic emissions signal and its components: A potential tool to investigate auditory processing disorder
Item
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Title
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Efferent-mediated changes in the composite distortion product otoacoustic emissions signal and its components: A potential tool to investigate auditory processing disorder
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Identifier
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d_2009_2013:b24fe7f6bfce:11879
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identifier
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12537
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Creator
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Abdelrazeq, Shukrallah,
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Contributor
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Glenis R. Long
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Date
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2013
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Language
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English
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Publisher
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City University of New York.
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Subject
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Audiology | auditory processing disorder | distortion product otoacoustic emissions | efferent anti-masking hypothesis | medial olivocochlear efferent system | overlap component | reflection component
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Abstract
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One of the hallmarks of auditory processing disorder (APD) is difficulty listening in background noise. This difficulty maybe related to the function of the medial olivocochlear (MOC) efferent system, which is hypothesized to provide an anti-masking effect that might aid in speech processing in noise. To test this hypothesis, we investigated the efferent anti-masking hypothesis via efferent-induced changes in the baseline levels of distortion product otoacoustic emissions (DPOAE) in a group of subjects suspected of having APD with speech-in-noise deficits matched for age and gender with a control group with less speech-in-noise deficits. There was no significant difference in audiometric thresholds between the groups. We examined not only the typical composite DPOAE, but also the two major components (overlap and reflection components), which determine the overall DPOAE level. We hypothesized that the group with speech-in-noise deficits would show reduced efferent effects relative to the control group. The findings did not support the efferent anti-masking hypothesis as efferent-induced changes in the composite DPOAE signal and the overlap component did not differ significantly between the two groups, but the statistical power was low. The separation of the two DPOAE components was beneficial in detecting efferent effects at the high frequency region where the DPOAE levels were lowest, and efferent effects were variable. The mean baseline levels and SNR of composite DPOAE and the overlap component were lower in the group with speech-in-noise deficits than the control group. This difference was not significant, but the statistical power was low. In addition, no significant correlations were found between performance on speech-in-noise tests and DPOAE change due to efferent activation across groups. Factors that might explain why the efferent anti-masking hypothesis was not supported are discussed.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Speech and Hearing Sciences
