Middle Ear Research
The Wallace Middle Ear Research Unit is co-directed by Professors John J. Rosowski, Ph.D. and Saumil N Merchant, M.D. Other members of the staff include Professor William T. Peake, Sc.D., Associate Scientist Michael E. Ravicz, M.S., Melissa Wood, as well as graduate students, residents and post-doctoral research fellows.
The goal of our research is to better understand sound transmission through normal, diseased and reconstructed middle ears, so that better diagnostic tests and therapeutic procedures can be offered to patients with middle-ear disease. Middle-ear diseases such as chronic otitis media and otosclerosis, which affect over 10 million people in the U.S., are common causes of significant conductive hearing loss.
Over the past 20 years, the laboratory has utilized a unique and powerful combination of methods to study middle ear mechanics, including in-vitro measurements in cadaveric human temporal bones, in-vivo measurements using audiometry and laser Doppler vibrometry, and physics-based quantitative modeling (see Figures attached below).
Our work has (a) provided insight into middle-ear sound transmission in the normal ear in humans and in a variety of mammalian species (b) resulted in better understanding of mechanisms of hearing loss in a variety of common pathologic conditions such as middle-ear fluid, ossicular fixation, ossicular discontinuity and third window lesions; (c) elucidated the structure-function relationships in a number of commonly performed surgical procedures, such as stapedectomy, tympanoplasty and mastoidectomy; (d) resulted in new tests employing laser vibrometry for improved preoperative differential diagnosis of ossicular lesions, and (e) provided specific surgical recommendations to optimize postoperative hearing results in certain types of middle ear surgical procedures.
1. Merchant SN, Rosowski JJ. Conductive hearing loss caused by third-window lesions of the inner ear. Otol Neurotol 2008; 29:282-289.
2. Rosowski JJ, Nakajima HH, Merchant SN. Clinical utility of laser-Doppler vibrometer measurements in live normal and pathologic human ears. Ear and Hearing 2008; 29:3-19
3. Chien W, Rosowski JJ, Merchant SN. Investigation of the mechanics of type III stapes columella tympanoplasty using laser Doppler vibrometry Otol Neurotol 2007; 28:782-787.
4. Voss SE, Rosowski JJ, Merchant SN, Peake WT. Non-ossicular signal transmission in human middle ears: experimental assessment of the “acoustic route” with perforated tympanic membranes. J Acoust Soc Am 2007;122:2135-2153.
5. Merchant SN, Nakajima HH, Halpin C, Nadol JB Jr, Lee DJ, Innis WP, Curtin H, Rosowski JJ. Clinical investigation and mechanism of air-bone gaps in large vestibular aqueduct syndrome. Annals Otol Rhinol Laryngol 2007; 116:532-541.
Legend: Interactive Research Approaches used in Wallace Middle Ear Research Unit :
Top- Middle ear models; Bottom left- Clinical hearing results; Bottom right- Acoustic measurements in cadaveric temporal bone preparation