# Middle Ear Nonlinearity in High Intensity Sound: Impact on Hearing Damage and Protection

> **NIH NIH R01** · MASSACHUSETTS EYE AND EAR INFIRMARY · 2022 · $420,645

## Abstract

ABSTRACT:
 Our ears are vulnerable to intense sounds (> 130 dB SPL) that can damage middle- and inner-ear
structures and produce temporary or permanent hearing loss. Prior research has focused on studying damage
to the cochlea, but relatively little is known of how the middle ear transmits extremely high-level damaging sounds
to the cochlea. While the middle ear muscle reflex elicited by high level steady state sounds can reduce sound
transmission to the cochlea, it cannot protect the ear during brief impulsive sounds. Nonlinear mechanisms of
the middle ear that can provide protection for impulsive sounds have been observed. However, there are few
quantitative studies of middle ear nonlinear processes, and the contributions of nonlinear mechanisms to the
frequency and level dependence of middle ear sound transfer are not well described. Furthermore, the etiologies
of middle ear structural failures produced by intense sounds are poorly known, as are their effects on middle ear
function. This lack of knowledge limits our ability to prevent such failures. There is also a lack of knowledge of
how surgically reconstructed middle ears with a passive prosthesis or graft work and their failure rate at high
level sounds. To tackle these questions, we propose three aims in this study. Aim 1 will use human cadaveric
temporal bones to systematically characterize middle ear nonlinear processes in time and frequency domains at
high intensity, in normal and reconstructed middle ears, to gain critical new knowledge on middle ear structure
and function at high sound levels. Aim 2 will extend the sound intensity to levels that can rupture the tympanic
membrane and other soft tissues to investigate the cause and time history of failures in normal and reconstructed
middle ears. For Aim 3, we propose to develop finite element middle ear nonlinear models that incorporate
multiple middle ear nonlinear mechanisms, including impulsive time-domain models and continuous tone
frequency-domain models. This study will impact our ability to predict noise-induced hearing damage,
development of new strategies for ear protection and improvements in the surgical repair of damaged middle
ears.

## Key facts

- **NIH application ID:** 10443501
- **Project number:** 2R01DC016079-06A1
- **Recipient organization:** MASSACHUSETTS EYE AND EAR INFIRMARY
- **Principal Investigator:** Jeffrey Tao Cheng
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $420,645
- **Award type:** 2
- **Project period:** 2017-02-08 → 2027-03-01

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10443501

## Citation

> US National Institutes of Health, RePORTER application 10443501, Middle Ear Nonlinearity in High Intensity Sound: Impact on Hearing Damage and Protection (2R01DC016079-06A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10443501. Licensed CC0.

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