The effects of age on acoustic reflex adaptation.
Item
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Title
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The effects of age on acoustic reflex adaptation.
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Identifier
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AAI8821102
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identifier
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8821102
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Creator
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Lynn, Deborah Jean.
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Contributor
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Arthur Boothroyd
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Date
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1988
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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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In recent years, numerous studies have focused on the effects of aging on selected measurements of the acoustic reflex. Although the measurement of acoustic reflex adaptation (or decay) has been used clinically in the differential diagnosis of auditory pathology, there have been no studies which have investigated how the aging process alters this measurement. The purpose of the present study was to investigate the effects of age and presbycusic hearing loss on the rate of reflex adaptation.;Three groups of 12 subjects each were used in this study: young normal subjects (ages 20-29), older normal hearing subjects (ages 60-69), and subjects with a mild to moderate presbycusic hearing loss (ages 60-69). The reflex activating stimuli consisted of tonal stimuli at.5, 1, and 2 KHz and a broad band noise presented at 10 dB and 15 dB above the subject's acoustic reflex threshold.;The rate of adaptation was calculated by using a time constant. Individual adaptation functions were fitted by the exponential equation y = a * e{dollar}\sp{lcub}\rm -bt{rcub}{dollar} and from this equation the time constant 1/b was derived. The time constant is the time in seconds taken for the admittance to decay by 63% of its maximum value. In addition to calculating the rate of adaptation for each function, the morphology of the curves were examined closely for trends. Four different curve patterns were discovered. Statistical analysis was performed on the rate and morphology data to determine group, stimulus type and sensation level effects.;The major conclusions drawn from this study were two. First, the rate of reflex adaptation was not significantly different across the three groups studied. That is, the rate was not significantly affected by age or presbycusis. Second, the data on the morphology of the decay curves indicated an age dependency. The basis for this age-related finding is not known. However, it appears that the reflex adaptation process may be more complex than typically assumed. Therefore, the use of a single estimate of decay rate (as commonly used in the clinical decay test) may overlook confounding detail of the adaptation function could have diagnostic value.
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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 and Hearing Sciences
