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An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions

BACKGROUND: The interference between the incoming sound wave and the acoustic energy reflected by the tympanic membrane (TM) forms a standing wave in human ear canals. The existence of standing waves causes various problems when measuring otoacoustic emissions (OAEs) that are soft sounds closely rel...

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Autores principales: Chen, Shixiong, Zhang, Haoshi, Wang, Lan, Li, Guanglin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4096431/
https://www.ncbi.nlm.nih.gov/pubmed/25001486
http://dx.doi.org/10.1186/1475-925X-13-95
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author Chen, Shixiong
Zhang, Haoshi
Wang, Lan
Li, Guanglin
author_facet Chen, Shixiong
Zhang, Haoshi
Wang, Lan
Li, Guanglin
author_sort Chen, Shixiong
collection PubMed
description BACKGROUND: The interference between the incoming sound wave and the acoustic energy reflected by the tympanic membrane (TM) forms a standing wave in human ear canals. The existence of standing waves causes various problems when measuring otoacoustic emissions (OAEs) that are soft sounds closely related with the functional status of the inner ear. The purpose of this study was to propose an in-situ calibration method to overcome the standing-wave problem and to improve the accuracy of OAE measurements. METHODS: In this study, the sound pressure level (SPL) at the TM was indirectly estimated by measuring the SPL at the entrance of the ear canal and the acoustic characteristics of the earphone system, so that sound energy entering the middle ear could be controlled more precisely. Then an in-situ calibration method based on the estimated TM SPL was proposed to control the stimulus level when measuring the stimulus frequency otoacoustic emissions (SFOAEs) evoked by swept tones. The results of swept-tone SFOAEs with the in-situ calibration were compared with two other calibration methods currently used in the clinic. RESULTS: Our results showed that the estimate of the SPL at the TM was rather successful with the maximal error less than 3.2 dB across all the six subjects. With the high definition OAE spectra achieved by using swept tones, it was found that the calibration methods currently used in the clinic might over-compensate the sound energy delivered to the middle ear around standing-wave frequencies and the SFOAE amplitude could be elevated by more than 7 dB as a consequence. In contrast, the in-situ calibration did not suffer from the standing-wave problem and the results could reflect the functional status of the inner ear more truthfully. CONCLUSIONS: This study suggests that calibration methods currently used in the clinic may produce unreliable results. The in-situ calibration based on the estimated TM SPL could avoid the standing-wave problem and might be incorporated into clinical OAE measurements for more accurate hearing loss screenings.
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spelling pubmed-40964312014-07-23 An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions Chen, Shixiong Zhang, Haoshi Wang, Lan Li, Guanglin Biomed Eng Online Research BACKGROUND: The interference between the incoming sound wave and the acoustic energy reflected by the tympanic membrane (TM) forms a standing wave in human ear canals. The existence of standing waves causes various problems when measuring otoacoustic emissions (OAEs) that are soft sounds closely related with the functional status of the inner ear. The purpose of this study was to propose an in-situ calibration method to overcome the standing-wave problem and to improve the accuracy of OAE measurements. METHODS: In this study, the sound pressure level (SPL) at the TM was indirectly estimated by measuring the SPL at the entrance of the ear canal and the acoustic characteristics of the earphone system, so that sound energy entering the middle ear could be controlled more precisely. Then an in-situ calibration method based on the estimated TM SPL was proposed to control the stimulus level when measuring the stimulus frequency otoacoustic emissions (SFOAEs) evoked by swept tones. The results of swept-tone SFOAEs with the in-situ calibration were compared with two other calibration methods currently used in the clinic. RESULTS: Our results showed that the estimate of the SPL at the TM was rather successful with the maximal error less than 3.2 dB across all the six subjects. With the high definition OAE spectra achieved by using swept tones, it was found that the calibration methods currently used in the clinic might over-compensate the sound energy delivered to the middle ear around standing-wave frequencies and the SFOAE amplitude could be elevated by more than 7 dB as a consequence. In contrast, the in-situ calibration did not suffer from the standing-wave problem and the results could reflect the functional status of the inner ear more truthfully. CONCLUSIONS: This study suggests that calibration methods currently used in the clinic may produce unreliable results. The in-situ calibration based on the estimated TM SPL could avoid the standing-wave problem and might be incorporated into clinical OAE measurements for more accurate hearing loss screenings. BioMed Central 2014-07-08 /pmc/articles/PMC4096431/ /pubmed/25001486 http://dx.doi.org/10.1186/1475-925X-13-95 Text en Copyright © 2014 Chen et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/4.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Chen, Shixiong
Zhang, Haoshi
Wang, Lan
Li, Guanglin
An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title_full An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title_fullStr An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title_full_unstemmed An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title_short An in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
title_sort in-situ calibration method and the effects on stimulus frequency otoacoustic emissions
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4096431/
https://www.ncbi.nlm.nih.gov/pubmed/25001486
http://dx.doi.org/10.1186/1475-925X-13-95
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