Article
Automated hearing threshold estimation using cochlea-scan technology in pediatric audiometry
Automatische Hörschwellenbestimmung mittels DPOAE in der pädaudiologischen Diagnostik
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Published: | September 7, 2006 |
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Outline
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Conditioned free-field play audiometry does not allow precise quantitative assessment of hearing loss in infants and young children. The descrepancy between behavioral and real threshold is known to be considerably high (up to 50 dB in infants). Moreover, due to the high discrepancy only poor frequency-specific information of the hearing loss can be yielded. Also, due to free-field stimulation a side-different determination of the hearing loss is not possible. The purpose of the present study was to evaluate the performance of a new automated and objective method (cochlea-scan technology) for frequency-specific and quantitative assessment of hearing loss in pediatric audiometry.
Hearing thresholds were recorded at five test-frequencies (f2 = 1.5, 2, 3, 4, and 5 kHz) by using a hand held system (cochlear-scan, Fischer-Zoth/Natus) based on extrapolated DPOAE I/O-functions (Boege and Janssen 2002). Hearing thresholds were presented in the form of an audiogram and referred to as a ‘DPOAE-audiogram’. DPOAE-audiograms were obtained in 83 infants and children aged between 3 months and 12 years who were seen in the pediatric ambulatorium of the ENT-department.
In the older children a close relation between DPOAE-audiogram and behavioral audiogram was found. The younger the child the higher was the discrepancy between objective and behavioral threshold. In infants with a suspected genetic hearing loss, DPOAE-audiograms indicated a mid-frequency hearing loss whereas behavioral audiograms did not exhibit any change in hearing loss across frequency. Also, in children who underwent chemotherapy, which is known to induce a high-frequency hearing loss, DPOAE-audiograms provided more frequency-specific information about the hearing loss than behavioral audiograms. In some cases side-different DPOAE-audiograms were found. Side-different hearing was confirmed by ABR.
Findings suggest cochlea-scan technology to be a siutable tool for assessing cochlear hearing loss in infants more precisely than behavioral hearing testings. A side-different determination of the hearing loss is possible. Due to the fact that cochlea-scan technology provides frequency-specific and quantitative information about the hearing loss more detailed information than otherwise obtained by commonly used automated OAE and ABR procedures can be yielded.
References
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- Boege P, Janssen T. Pure-tone threshold estimation from extrapolated distortion product otoacoustic emission I/O-functions in normal and cochlear hearing loss ears. J Acoust Soc Am. 2002; 88: 1810-1818