INTER-EAR ASYMMETRY AND BINAURAL INTERACTION IN THE BRAINSTEM AUDITORY EVOKED POTENTIALS (HEARING).
Item
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Title
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INTER-EAR ASYMMETRY AND BINAURAL INTERACTION IN THE BRAINSTEM AUDITORY EVOKED POTENTIALS (HEARING).
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Identifier
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AAI8515664
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identifier
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8515664
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Creator
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SPIVAK, LYNN G.
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Contributor
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Michael B. Seitz
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Date
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1985
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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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Health Sciences, Audiology
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Abstract
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Evidence of binaural interaction has been found in the brainstem auditory evoked potentials (BSAEP). This evidence, which takes the form of a difference trace when the monaural responses are summed and subtracted from the binaural response, however, is subject to artifactual contamination which is introduced when the BSAEP waveforms are subjected to algebraic operations. Right/left response asymmetry has been identified as a confounding variable in studies of binaural interaction.;This study examined right/left response asymmetry and its relationship to measurements of binaural interaction. It was hypothesized that response asymmetry would be present in the monaural responses of a significant number of normal hearing subjects and that the presence of significant asymmetry would cause the sum of right and left monaural responses to be a poor predictor of the binaural response, thereby resulting in a large difference trace (residual component) when the binaural response was subtracted from the combined monaural response.;Right, left, and binaural BSAEPs were recorded from 24 normal hearing subjects at 70 and 50 dB SL. Monaural responses were classified as asymmetrical when the amplitude of right - left difference trace exceeded the amplitude of the background noise. When significant asymmetry was present, the interaural intensity of the stimuli was adjusted in an attempt to reduce the asymmetry.;A significant proportion of normal hearing subjects had asymmetrical monaural BSAEPs. Classification of responses as asymmetrical was dependent on the operational definition of asymmetry, the criterion used, and the sensation level of the stimulus. Five different patterns of asymmetry were identified depending on the inter-ear wave V latency and amplitude relationships. The degree of asymmetry present was positively correlated with the amplitude of the residual component. It was found that ineraural intensity adjustments significantly reduced asymmetry. When asymmetry was reduced, the amplitude of the residual component was significantly reduced.;It was concluded that inter-ear asymmetry in the BSAEP is the rule rather than the exception. The significant correlation between the degree of inter-ear asymmetry and the amplitude of the residual component indicated that asymmetry is an important factor which must be accounted for in studies of binaural interaction in the BSAEP.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Speech & Hearing
