Middle-ear disease is the most common cause of hearing loss. Otologic surgeons repair thousands of middle ears each year with mixed success, especially after severe middle-ear disease. Knowledge of structure-function relationships is crucial to improving reconstructive techniques. Attractive treatments for severe conductive hearing loss include direct mechanical stimulation of the cochlear windows and/or the application of bone-conduction hearing aids. In the past, we developed physiology-based models that relate structure and function in normal, pathological, and reconstructed ears. We focus now on four clinically-relevant structure-function issues using animal models: (1) We investigate the source and functional significance of observed delays in normal and modified middle-ear transmission in cat and chinchilla in the context of middle-ear impedance matching, the efficiency of sound transmission and the high-frequency response of the intact and pathologic middle ear. (2) We quantify the efficacy of direct round- and oval-window stimulation in a live animal model (chinchilla) and use these results to refine a model of cochlear function that accounts for the observed effectiveness of such stimulation in cases of round and oval-window fixation. (3) We build on our past research showing the significance of the inner-ear mechanism of bone conduction in chinchilla, and use this preparation to investigate (a) the mechanisms that contribute to the ear's response to bone conducted sound after ossicular pathology and (b) provide a fundamental test of the influence of cranial tissue vibrations on the ear's response to bone-conducted sound. (4) We use a newly developed bone-conduction-based method to quantify 'conductive'and 'sensorineural'hearing loss in mouse models of mixed hearing loss. Such a separation is critical in understanding the mechanisms of various genetic models of hearing loss.

Public Health Relevance

Middle-ear disease is the most common form of hearing loss, and otologic surgeons routinely repair middle ears but with variable success. This proposal answers questions on the basic mechanisms of middle-ear sound transfer and how the inner ear is stimulated by ossicular prostheses. It also investigates the pathways for bone-conduction hearing and uses bone conduction to define measures that distinguish between middle-ear and inner-ear related hearing losses in animal models of human ear disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
2R01DC000194-30A1
Application #
8694222
Study Section
Auditory System Study Section (AUD)
Program Officer
Watson, Bracie
Project Start
1983-01-01
Project End
2019-02-28
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
30
Fiscal Year
2014
Total Cost
$409,357
Indirect Cost
$141,928
Name
Massachusetts Eye and Ear Infirmary
Department
Type
DUNS #
073825945
City
Boston
State
MA
Country
United States
Zip Code
02114
Chang, Ernest W; Cheng, Jeffrey T; Roosli, Christof et al. (2013) Simultaneous 3D imaging of sound-induced motions of the tympanic membrane and middle ear ossicles. Hear Res 304:49-56
Rosowski, John J; Nakajima, Hideko H; Hamade, Mohamad A et al. (2012) Ear-canal reflectance, umbo velocity, and tympanometry in normal-hearing adults. Ear Hear 33:19-34
Qin, Zhaobing; Wood, Melissa; Rosowski, John J (2010) Measurement of conductive hearing loss in mice. Hear Res 263:93-103
Slama, Michael C C; Ravicz, Michael E; Rosowski, John J (2010) Middle ear function and cochlear input impedance in chinchilla. J Acoust Soc Am 127:1397-410
Ravicz, Michael E; Slama, Michael C C; Rosowski, John J (2010) Middle-ear pressure gain and cochlear partition differential pressure in chinchilla. Hear Res 263:16-25
Songer, Jocelyn E; Rosowski, John J (2010) A superior semicircular canal dehiscence-induced air-bone gap in chinchilla. Hear Res 269:70-80
Chien, Wade; Rosowski, John J; Ravicz, Michael E et al. (2009) Measurements of stapes velocity in live human ears. Hear Res 249:54-61
Rosowski, John J (2009) Comment on "When an air-bone gap is not a sign of a middle-ear conductive loss" By Sohmer et al. Ear Hear 30:149-150
Ravicz, Michael E; Cooper, Nigel P; Rosowski, John J (2008) Gerbil middle-ear sound transmission from 100 Hz to 60 kHz. J Acoust Soc Am 124:363-80
Yelin, Dvir; Bouma, B E; Rosowsky, J J et al. (2008) Doppler imaging using spectrally-encoded endoscopy. Opt Express 16:14836-44

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