Publication Date

2013

Document Type

Honors Thesis

Department

Engineering

Keywords

Intracranial pressure-Measurement, Otoacoustic emissions, Lumped elements (Electronics), Middle ear-Physiology, Middle ear-Pathophysiology, Ear-Models, Distortion product otoacoustic emissions, DPOAEs, Lumped element model, Network model, Ear model, Auditory system, Ear

Abstract

Elevated intracranial pressure (ICP) is a condition that arises from a number of causes, both traumatic and chronic. Currently, the only ways to monitor ICP clinically are highly invasive. Distortion product otoacoustic emissions (DPOAEs) have been shown to change with ICP. As part of the long-term goal to assess the potential of DPOAEs as a non-invasive measure of ICP, it is important to understand the causes of these changes. It is presently hypothesized that sti ening of the annular ligament of the stapes attenuates the transmission of the primaries to the cochlea and DPOAE from the cochlea, predominantly causing the changes in DPOAEs with ICP. The goal of the present work is to design a comprehensive model of the ear for the prediction of DPOAEs in order to understand why DPOAEs change with ICP. DPOAEs from two subjects were measured at 16 frequencies between 500 and 4000 Hz for both t and validation of the model. Middle ear compliances were sti ened systematically in the tting of the model. Fitting and validation of the model showed that the model was able to roughly predict measured DPOAEs in the case of elevated ICP when the annular ligament was sti ened by a factor of 2.7 { 5.2 times, the malleus was sti ened 1.7 { 2.9 times, the IM joint 1 { 2.3 times, and the IS joint was shown to have little e ect on DPOAE changes with ICP. Sti ening of the annular ligament alone was not able to predict changes in DPOAEs with ICP as well as changes to all middle ear compliances.

Language

English

Comments

75 p. : col. ill. Honors project-Smith College, 2013. Includes bibliographical references (p. 62-[64})

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