Comparative approaches to otoacoustic emissions : towards and understanding of why the ear emits sound

The ear represents a remarkable achievement in sensory physiology. It is very fast (timescales on the order of 1-100 kHz), has a large bandwidth (-10 octaves in the human), highly sensitive (threshold is ultimately determined by thermal noise), operates over an enormous dynamic range (factor of a trillion in terms of energy input), capable of sharp stimulus selectivity (e.g. frequency and intensity discrimination) and exhibits robust nonlinear behavior. As a sensor designed to detect acoustic sound pressure, surprisingly, the ear also emits sound as well. These otoacoustic emissions (OAEs) have been developed extensively for clinical applications (healthy ears emits while impaired ones do not), though their full potential has yet to be realized. Much of the effort gone into understanding OAEs has been developed within the context of mammals, where specific anatomical and physiological features (e.g. traveling waves and somatic motility) are thought to play an integral role in generation. This thesis approaches OAEs comparatively, systematically characterizing emissions in humans and an array of non-mammals (chickens, geckos and frogs) who lack these mammalian features and exhibit a diverse range of morphologies.

Department dc:contributor.department

Harvard University--MIT Division of Health Sciences and Technology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Bergevin, Christopher

Advisor dc:contributor.advisor

• Christopher A. Shera and Dennis M. Freeman.

• Harvard University--MIT Division of Health Sciences and Technology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/39572
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/39572

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/39572