Document Type
Article
Publication Date
2001
Publication Title
The Journal of the Acoustical Society of America
Abstract
Sound transmission through ears with tympanic-membrane ~TM! perforations is not well understood. Here, measurements on human-cadaver ears are reported that describe sound transmission through the middle ear with experimentally produced perforations, which range from 0.5 to 5.0 mm in diameter. Three response variables were measured with acoustic stimulation at the TM: stapes velocity, middle-ear cavity sound pressure, and acoustic impedance at the TM. The stapes-velocity measurements show that perforations cause frequency-dependent losses; at low frequencies losses are largest and increase as perforation size increases. Measurements of middle-ear cavity pressure coupled with the stapes-velocity measurements indicate that the dominant mechanism for loss with TM perforations is reduction in pressure difference across the TM; changes in TM-to-ossicular coupling generally contribute less than 5 dB to the loss. Measurements of middle-ear input impedance indicate that for low frequencies, the input impedance with a perforation approximates the impedance of the middle-ear cavity; as the perforation size increases, the similarity to the cavity’s impedance extends to higher frequencies. The collection of results suggests that the effects of perforations can be represented by the path for air-volume flow from the ear canal to the middle-ear cavity. The quantitative description of perforation-induced losses may help clinicians determine, in an ear with a perforation, whether poor hearing results only from the perforation or whether other pathology should be expected.
Volume
110
First Page
1432
Last Page
1444
DOI
10.1121/1.1394195
Rights
© 2001 Acoustical Society of America.
Recommended Citation
Voss, Susan E.; Rosowski, John J.; Merchant, Saumil N.; and Peake, William T., "Middle-Ear Function with Tympanic-Membrane Perforations. I. Measurements and Mechanisms" (2001). Engineering: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/egr_facpubs/141
Comments
Archived as published.