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 relations is crucial to improving reconstructive techniques. In the past, we developed physiology-based models that relate structure and function in normal ears, pathological ears and reconstructed ears. We focus now on four new clinically-relevant structure- function issues: (1) We quantify the contribution of the middle ear to the shape of the auditory threshold curve by (a) comparing middle-ear inputs and outputs to quantify the power transfer efficiency of the middle-ear in individual animals, (b) comparing estimates of middle-ear output at physiologic threshold in live animals. Near constant levels of middle-ear output at threshold would imply the middle ear plays a dominant role in shaping normal auditory thresholds. (2) We investigate the contribution of the round window and natural or pathologic `third windows'to normal, pathological and aided middle-ear function. Normal and pathologic inner-ear windows are potential pathways for stimulating the cochlea as well as potential shunt paths for directing sound power away from the cochlea. This work will determine how the round window and different `third windows'into the inner ear affect sensitivity to airborne sound and assess their potential as pathways for cochlear stimulation. (3) We will quantify the relative contributions of different bone- conduction pathways. Recent reports come to contradictory conclusions on the clinical significance of compressive bone conduction, and point to a sensitivity of this mechanism to inner-ear conductive pathology. We quantify the contribution of cochlear compression relative to other bone- conduction mechanisms and test whether changes in bone-conducted thresholds with `third- window'pathologies are explained by cochlear compression. (4) We test methods, including laser- Doppler vibrometry and bone-conduction stimulation, to separate `conductive'and `sensory-neural' hearing loss phenotypes in animal models of hearing loss. This 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 is designed to answer questions on the mechanisms of middle- and inner-ear conductive losses that result from middle and inner-ear abnormalities. It will also investigate the pathways for bone-conduction hearing and use bone conduction to define measures that better distinguish between middle-ear and inner- ear related hearing losses.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC000194-29
Application #
8304132
Study Section
Auditory System Study Section (AUD)
Program Officer
Miller, Roger
Project Start
1983-01-01
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2014-08-31
Support Year
29
Fiscal Year
2012
Total Cost
$307,501
Indirect Cost
$103,858
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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