Transient-Evoked Otoacoustic Emissions as a Measure of Noise-Induced Threshold Shift Otoacoustic emissions and behavioral hearing thresholds were measured before and after exposure to a 10-min, 105-dB SPL, half-octave band of noise centered at 1.414 kHz. Along a single recovery function, transient-evoked otoacoustic-emission (TEOAE) measurements made with 74-dB pSPL nonlinear click ensembles were alternated with a Bekesy threshold-tracking procedure. Each of ... Research Article
Research Article  |   December 01, 1998
Transient-Evoked Otoacoustic Emissions as a Measure of Noise-Induced Threshold Shift
 
Author Affiliations & Notes
  • Lynne Marshall
    Naval Submarine Medical Research Laboratory Groton, Connecticut
  • Laurie M. Heller
    Naval Submarine Medical Research Laboratory Groton, Connecticut
  • Contact author: Lynne Marshall, PhD, Naval Submarine Medical Research Laboratory, Box 900, Subase NLON, Groton, CT 06349. Email: marshall@nsmrl.navy.mil
Article Information
Hearing & Speech Perception / Acoustics / Hearing Disorders / Research Issues, Methods & Evidence-Based Practice / Hearing / Research Articles
Research Article   |   December 01, 1998
Transient-Evoked Otoacoustic Emissions as a Measure of Noise-Induced Threshold Shift
Journal of Speech, Language, and Hearing Research, December 1998, Vol. 41, 1319-1334. doi:10.1044/jslhr.4106.1319
History: Received January 16, 1998 , Accepted August 24, 1998
 
Journal of Speech, Language, and Hearing Research, December 1998, Vol. 41, 1319-1334. doi:10.1044/jslhr.4106.1319
History: Received January 16, 1998; Accepted August 24, 1998

Otoacoustic emissions and behavioral hearing thresholds were measured before and after exposure to a 10-min, 105-dB SPL, half-octave band of noise centered at 1.414 kHz. Along a single recovery function, transient-evoked otoacoustic-emission (TEOAE) measurements made with 74-dB pSPL nonlinear click ensembles were alternated with a Bekesy threshold-tracking procedure. Each of the 14 participants with normal hearing underwent 2 hour-long temporary-threshold shift (TTS) sessions as well as 2 pretest sessions and a posttest session. The Bekesy test frequency was fixed at 2.0 kHz, whereas emissions were analyzed in half-octave bandwidths with center frequencies ranging from 0.707 to 5.656 kHz. Results showed that (a) the maximum temporary emission shifts (TES) were half 1 octave above the exposure frequency; (b) the 4.7-dB average temporary emission shift magnitude at approximately 2 min postexposure was less than half of the 11.7-dB average TTS; (c) the average recovery times for emissions and hearing thresholds were similar (188 vs. 186 min); and (d) the average TTS magnitude along the recovery function was predictable from TES magnitude. It concluded that both TEOAEs and Bekesy thresholds reveal the same aspects of postexposure inner-ear changes.

Acknowledgments
The authors wish to thank Jim Patterson for assistance with the Bekesy psychophysical procedure. Kelley Mascher provided the software and hardware for switching between the stimuli for TEOAEs, noise exposures, and behavioral testing, and both Susan Norton and he helped plan the study. Barbara Lentz, Linda Westhusin, and Jon Hromi collected the data, and HM1 Lentz also assisted with the data analyses. Keith Larson designed the plot showing the timing of the testing during the experimental session and the 3-D plots, and HM1 Lentz did the other plots. Ed Cudahy and Tom Hanna gave many helpful comments on an earlier version of this manuscript. An anonymous reviewer also provided useful comments. Portions of this work were presented at the twentieth midwinter research meeting of the Association for Research in Otolaryngology, Saint Petersburg Beach, Florida, February, 1997. This work was supported by a grant from the Office of Naval Research. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government.
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