Functional implications of flexibility in the mammalian middle ear
Abstract/Contents
- Abstract
- The middle ear in terrestrial vertebrates exists to transmit acoustic signals from the environment into the fluid-filled inner ear, where they are transduced into electrical signals that can be interpreted by the brain. In mammals, the middle ear is uniquely characterized by the presence of three distinct ossicles, which are suspended in the air-filled middle ear cavity by a combination of ligaments, tendons, and in some cases, thin bony structures. The functional benefits of the flexibility afforded by this complicated anatomy are still debated. The goal of this work is to test the role of this flexibility by using a combination of experimental and computational methods to systematically remove sources of flexibility in the mammalian middle ear chain and measure the effects of these modifications. Three main studies are discussed. First, the middle ear ossicles in human specimens were replaced with artificial prostheses, which removed both the joint flexibility and the flexibility inherent in the bones themselves. Second, the ossicular joints in the human middle ear were sequentially fused in order to examine their role in more detail. Finally, sound transmission was characterized in the mouse middle ear as a case study of a mammalian middle ear with dramatically different characteristics and sources of flexibility than the human middle ear. In all three studies, a combination of experimental 3D vibration measurements and finite element modeling was used to explore the middle ear system and modifications. Experiments and simulations were performed in both the frequency domain as well as in the time domain to understand the role of middle ear flexibility in transmitting complex impulsive sounds in addition to pure sinusoidal signals. The results showed that while modifying the human ossicular chain with prostheses had no significant effect, on average, in the frequency domain, fusing the ossicular joints caused a significant increase in peak stapes velocity in response to an impulsive stimulus. In the mouse, the flexibility of ossicular joints appears to be less important than that of the malleus bone itself. These findings have interesting implications for both clinical questions relating to pathologies that increase ossicular joint stiffness as well as the basic scientific understanding of sound transmission through the human and mouse middle ears.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Gottlieb, Peter Kirsh |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Puria, Sunil |
| Primary advisor | Steele, Charles R. (Charles Reginald), 1944- |
| Thesis advisor | Puria, Sunil |
| Thesis advisor | Steele, Charles R. (Charles Reginald), 1944- |
| Thesis advisor | Kuhl, Ellen |
| Thesis advisor | Oghalai, John S |
| Advisor | Kuhl, Ellen |
| Advisor | Oghalai, John S |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Peter Kirsh Gottlieb. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Peter Kirsh Gottlieb
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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