On the Use of Envelope Following Responses to Estimate Peripheral Level Compression in the Auditory System

Author:

Encina-Llamas GerardORCID,Dau TorstenORCID,Epp BastianORCID

Abstract

ABSTRACTHearing impairment is a common and increasingly frequent problem among elderly people. The success of restoration or compensation therapies is strongly dependent on the development of reliable diagnostic methods for individual patients. The ability to compress the large level range of incoming sounds into a smaller range of vibration amplitudes on the basilar membrane (BM) is an important property of the healthy auditory system. Sensorineural hearing impairment typically leads to a decrease in sensitivity to sound and a reduction of the amount of compression observed in BM input-output functions in the cochlea. While sensitivity loss can be measured efficiently via audiometry, no measure has yet been provided that represents fast and reliable compression estimates in the individual listener. This would be useful to disentangle outer hair cells (OHC) from inner hair cells (IHC) damage. In the present study, magnitude-level functions obtained from envelope following response (EFR) to four simultaneously presented amplitude modulated tones were measured in normal hearing (NH) and sensorineural hearing impaired (HI) listeners. The slope of part of the EFR magnitude-level function was used to estimate level compression as a proxy of peripheral compression. The median values of the compression estimates in the group of NH listeners were found to be consistent with previously reported group-averaged compression estimates based on psychoacoustical measures and group-averaged distortion-product otoacoustic emission magnitude-level functions in human listeners. They were also similar to BM compression values measured invasively in non-human mammals. The EFR magnitude-level functions for the HI listeners were less compressive than those for the NH listeners. This is consistent with a reduction of BM compression. Given the numerical concordance between EFR-based compression estimates and group-averaged estimates from other methods, the frequency-specific (on-characteristic frequency (CF)) nature of BM compression was analysed through computer modelling. A computer model of the auditory nerve (AN) was used to simulate EFR magnitude-level functions at the level of the AN. The recorded EFRs were considered to represent neural activity originating mainly from the auditory brainstem-midbrain rather than a direct measure of AN activity. Nonetheless, the AN model simulations could account for the recorded data. The model simulations revealed that the growth of the EFR magnitude-level function might be highly influenced by contributions from off-CF neural populations. This compromises the possibility to estimate on-CF (i.e., frequency-specific or “local”) level compression with EFRs. Furthermore, the model showed that, while the slope of the EFR magnitude-level function is sensitive to a loss of BM compression observed in HI listeners due to OHC dysfunction, it is also sensitive to IHC dysfunction. Overall, it is concluded that EFR magnitude-level functions may not represent frequency-specific level compression in the auditory system.

Publisher

Cold Spring Harbor Laboratory

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3