Encina Llamas, Gerard

Epp, Bastian

M. Harte, James

The compressive nonlinearity of the auditory system is assumed to be an epiphenomenon of a healthy cochlea and, particularly, of outer-hair cell function. Another ability of the healthy auditory system is to enable communication in acoustical environments with high-level background noises. Evaluation of these properties provides information about the health state of the system. It has been shown that a loss of outer hair cells leads to a reduction in peripheral compression. It has also recently been shown in animal studies that noise over-exposure, producing temporary threshold shifts, can cause auditory nerve fiber (ANF) deafferentation in predominantly low-spontaneous rate (SR) fibers. In the present study, auditory steadystate response (ASSR) level growth functions were measured to evaluate the applicability of ASSR to assess compression and the ability to code intensity fluctuations at high stimulus levels. Level growth functions were measured in normal-hearing adults at stimulus levels ranging from 20 to 90 dB SPL. To evaluate compression, ASSR were measured for multiple carrier frequencies simultaneously. To evaluate intensity coding at high intensities, ASSR were measured using a single carrier frequency at four modulation depths between 25 and 100%. The data showed that ASSR level growth functions exhibited compression of about 0.25 dB/dB. For levels above 60 dBSPL, the slope showed higher variability for the different modulation depths across subjects than for lower levels. The results indicate that the slope of the ASSR level growth function can be used to estimate peripheral compression simultaneously at four frequencies below 60 dB SPL, while the slope above 60 dB SPL may provide information about the integrity of intensity coding of low-SR fibers

Online Research Database In Technology

Evaluation of peripheral compression and auditory nerve fiber intensity coding usingauditory steady-state responses - DTU Orbit (08/11/2017) Evaluation of peripheral compression and auditory nerve fiber intensity coding using auditory steady-state responsesThe compressive nonlinearity of the auditory system is assumed to be an epiphenomenon of a healthy cochlea and,particularly, of outer-hair cell function. Another ability of the healthy auditory system is to enable communication inacoustical environments with high-level background noises. Evaluation of these properties provides information about thehealth state of the system. It has been shown that a loss of outer hair cells leads to a reduction in peripheral compression.It has also recently been shown in animal studies that noise over-exposure, producing temporary threshold shifts, cancause auditory nerve fiber (ANF) deafferentation in predominantly low-spontaneous rate (SR) fibers. In the present study,auditory steadystate response (ASSR) level growth functions were measured to evaluate the applicability of ASSR toassess compression and the ability to code intensity fluctuations at high stimulus levels. Level growth functions weremeasured in normal-hearing adults at stimulus levels ranging from 20 to 90 dB SPL. To evaluate compression, ASSRwere measured for multiple carrier frequencies simultaneously. To evaluate intensity coding at high intensities, ASSRwere measured using a single carrier frequency at four modulation depths between 25 and 100%. The data showed thatASSR level growth functions exhibited compression of about 0.25 dB/dB. For levels above 60 dB SPL, the slope showed higher variability for the different modulation depths across subjects than for lower levels. Theresults indicate that the slope of the ASSR level growth function can be used to estimate peripheral compressionsimultaneously at four frequencies below 60 dB SPL, while the slope above 60 dB SPL may provide information about theintegrity of intensity coding of low-SR fibers. General informationState: PublishedOrganisations: Department of Electrical Engineering, Hearing Systems, Interacoustics A/SAuthors: Encina Llamas, G. (Intern), M. Harte, J. (Ekstern), Epp, B. (Intern)Number of pages: 8Publication date: 2015 Host publication informationTitle of host publication: Proceedings of ISAAR 2015Editors: Santurette, S., Dau, T., Dalsgaard, J. C., Tranebjærg, L., Andersen, T.ISBN (Print): 978-87-990013-5-4Main Research Area: Technical/natural sciencesSource: PublicationPreSubmissionSource-ID: 123057990Publication: Research - peer-review › Article in proceedings – Annual report year: 2016 

Evaluation of peripheral compression and auditory nerve fiber intensity coding using auditory steady-state responses

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Evaluation of peripheral compression and auditory nerve fiber intensity coding using auditory steady-state responses

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