THE EFFECT OF STIMULUS CENTER FREQUENCY AND BANDWIDTH ON THE RESPONSE-TIME OF THE HUMAN ACOUSTIC REFLEX.
Item
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Title
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THE EFFECT OF STIMULUS CENTER FREQUENCY AND BANDWIDTH ON THE RESPONSE-TIME OF THE HUMAN ACOUSTIC REFLEX.
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Identifier
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AAI8515662
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identifier
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8515662
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Creator
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SIRLIN, MINDY WERTHEIMER.
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Contributor
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Harry Levitt
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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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Acoustic reflex response-time, defined as the time (in msec) between stimulus onset and 10% of the maximum impedance change caused by the acoustic reflex, was measured in ten normal young adult subjects. Five of the subjects exhibited a biphasic response and five exhibited a uniphasic response.;Prior to the main experiment, a new procedure for simulating the phase and amplitude changes caused in the ear by the acoustic reflex was used to determine whether and to what extent the measuring equipment was adding to the observed response-times. The equipment used in this study had virtually no delay in response and had a rise time of approximately 12 msec to an electrically simulated reflex. These findings indicated that the instrumentation was accurately tracking the impedance change caused by the reflex.;In the main experiment, stimuli consisted of five bandwidths (1/6, 1/3, 1, 2 and 4 octaves) centered at three frequencies (500, 1000 and 4000 Hz) presented both at ART and at 10 dB above ART.;The data indicated that acoustic reflex response time is significantly faster for 500 Hz stimulation than it is for 4000 Hz stimulation. There were no significant differences between biphasic and uniphasic response times. Changes in bandwidth did not result in significant changes in response-time at 500 or 1000 Hz. At 4000 Hz, for signals wider than an octave, acoustic reflex response-time was significantly shorter than it was for signals narrower than an octave. The small initial negative peak of the biphasic reflex behaved differently than the major observed portion of the response.;There were important differences between ART and reflex response-time. The effect of frequency on response-time was opposite that of the effect of frequency on ART. While there is a critical band effect for acoustic reflex threshold, there is not a critical band for acoustic reflex response time.
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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
