Changes in distortion product otoacoustic emissions during prolonged noise exposure

被引:25
作者
Eddins, AC [1 ]
Zuskov, M
Salvi, RJ
机构
[1] Indiana Univ, Dept Speech & Hearing Sci, Auditory Physiol Lab, Bloomington, IN 47405 USA
[2] SUNY Buffalo, Dept Commun Disorders & Sci, Hearing Res Lab, Buffalo, NY 14260 USA
关键词
distortion product; otoacoustic emission; noise-induced hearing loss; chinchilla;
D O I
10.1016/S0378-5955(98)00182-8
中图分类号
R36 [病理学]; R76 [耳鼻咽喉科学];
学科分类号
100104 ; 100213 ;
摘要
The aim of this study was to evaluate the reduction in 2f(1)-f(2) distortion product otoacoustic emission (DPOAE) amplitude resulting from prolonged noise exposures. A group of five chinchillas was exposed continuously to an octave-band noise centered at 4.0 kHz for a total of 42 days, 6 days at each of seven exposure levels. Exposure level increased in 8-dB steps from 48 to 96 dB SPL. DPOAE input-output (I/O) functions were measured at octave intervals over a range of primary tone fi frequencies between 1.2 and 9.6 kHz. Measurements were obtained (1) pre-exposure, (2) during days 3-6 of each 6-day exposure, and (3) 3 weeks after the final exposure. Continuous noise exposure caused a reduction in DPOAE amplitude that was greatest at f(2) frequencies within and above (3.4-6.8 kHz) the octave-band noise exposure. For these f(2) frequencies, DPOAE amplitudes decreased as exposure level increased up to approximately 72-80 dB SPL; higher exposure levels failed to cause any further reduction in DPOAE amplitude. The noise level at which DPOAE amplitude began to decrease was approximately 50 dB SPL. Above this critical level, DPOAE amplitude decreased 1.3 dB for every dB increase in noise level up to approximately 75 dB SPL. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
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页码:119 / 128
页数:10
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