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Optimization of the diagnosis of noise-induced hearing loss with otoacoustic emissions

Hannah Keppler UGent (2010)
abstract
Excessive noise exposure induces alterations of the structural elements of the organ of Corti, especially at the level of the outer hair cells (OHCs). Prolonged noise exposure leads to a gradually developing sensorineural hearing loss (noise-induced hearing loss, NIHL). However, an extensive amount of OHCs can be damaged without concomitant hearing loss established by pure-tone audiometry. Therefore, an alternative technique, evoked otoacoustic emissions (EOAEs), is suggested as a sensitive tool in the detection of NIHL. Amplitude reductions or absence of EOAEs reflect OHC damage, and are promising in the detection of pre-clinical NIHL. However, sensitive and reliable identification and monitoring of inner-ear damage caused by noise exposure is compromised by the large inter-subject variability of EOAEs. The goal of this thesis was to contribute to the knowledge regarding EOAEs in the early detection of NIHL. First, the technique of EOAEs and its influencing variables were explored. Second, the applicability of EOAEs in recreationally exposed subjects was evaluated. Regarding the first research aim, the effects of aging on EOAEs, the test-retest reliability of EOAEs, and the role of efferent suppression (ES) in the prediction of temporary hearing damage was evaluated. We found that deteriorated EOAE amplitudes with age are the result of age-related peripheral hearing loss superimposed on pure age-effects. EOAEs can also be used to monitor cochlear hearing status over time. Further, no relationship between the amount of temporary hearing damage and the magnitude of ES was seen. However, the noise-protective role of the auditory efferent system cannot be ruled out. With regard of the second research aim, we found that EOAEs were able to detect temporary effects of recreational noise exposure, as well as to differentiate between subjects with different attitudes regarding noise exposure, hearing loss and use of hearing protector devices. In conclusion, EOAEs can be used to identify and monitor subtle inner-ear changes, but the technique can still be improved with regard to its measurability and reliability.
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author
promoter
UGent and UGent
organization
year
type
dissertation
publication status
published
subject
keyword
Noise-induced hearing loss, otoacoustic emissions
pages
222 pages
publisher
Ghent University. Faculty of Medicine and Health Sciences
place of publication
Ghent, Belgium
defense location
Gent : UZ (auditorium E)
defense date
2010-06-28 17:30
language
English
UGent publication?
yes
classification
D1
additional info
dissertation consists of copyrighted materials
copyright statement
I have transferred the copyright for this publication to the publisher
id
1079594
handle
http://hdl.handle.net/1854/LU-1079594
date created
2010-11-25 14:26:21
date last changed
2017-01-16 10:37:57
@phdthesis{1079594,
  abstract     = {Excessive noise exposure induces alterations of the structural elements of the organ of Corti, especially at the level of the outer hair cells (OHCs). Prolonged noise exposure leads to a gradually developing sensorineural hearing loss (noise-induced hearing loss, NIHL). However, an extensive amount of OHCs can be damaged without concomitant hearing loss established by pure-tone audiometry. Therefore, an alternative technique, evoked otoacoustic emissions (EOAEs), is suggested as a sensitive tool in the detection of NIHL. Amplitude reductions or absence of EOAEs reflect OHC damage, and are promising in the detection of pre-clinical NIHL. However, sensitive and reliable identification and monitoring of inner-ear damage caused by noise exposure is compromised by the large inter-subject variability of EOAEs. 
The goal of this thesis was to contribute to the knowledge regarding EOAEs in the early detection of NIHL. First, the technique of EOAEs and its influencing variables were explored. Second, the applicability of EOAEs in recreationally exposed subjects was evaluated. 
Regarding the first research aim, the effects of aging on EOAEs, the test-retest reliability of EOAEs, and the role of efferent suppression (ES) in the prediction of temporary hearing damage was evaluated. We found that deteriorated EOAE amplitudes with age are the result of age-related peripheral hearing loss superimposed on pure age-effects. EOAEs can also be used to monitor cochlear hearing status over time. Further, no relationship between the amount of temporary hearing damage and the magnitude of ES was seen. However, the noise-protective role of the auditory efferent system cannot be ruled out. With regard of the second research aim, we found that EOAEs were able to detect temporary effects of recreational noise exposure, as well as to differentiate between subjects with different attitudes regarding noise exposure, hearing loss and use of hearing protector devices. 
In conclusion, EOAEs can be used to identify and monitor subtle inner-ear changes, but the technique can still be improved with regard to its measurability and reliability.},
  author       = {Keppler, Hannah},
  keyword      = {Noise-induced hearing loss,otoacoustic emissions},
  language     = {eng},
  pages        = {222},
  publisher    = {Ghent University. Faculty of Medicine and Health Sciences},
  school       = {Ghent University},
  title        = {Optimization of the diagnosis of noise-induced hearing loss with otoacoustic emissions},
  year         = {2010},
}

Chicago
Keppler, Hannah. 2010. “Optimization of the Diagnosis of Noise-induced Hearing Loss with Otoacoustic Emissions”. Ghent, Belgium: Ghent University. Faculty of Medicine and Health Sciences.
APA
Keppler, H. (2010). Optimization of the diagnosis of noise-induced hearing loss with otoacoustic emissions. Ghent University. Faculty of Medicine and Health Sciences, Ghent, Belgium.
Vancouver
1.
Keppler H. Optimization of the diagnosis of noise-induced hearing loss with otoacoustic emissions. [Ghent, Belgium]: Ghent University. Faculty of Medicine and Health Sciences; 2010.
MLA
Keppler, Hannah. “Optimization of the Diagnosis of Noise-induced Hearing Loss with Otoacoustic Emissions.” 2010 : n. pag. Print.