Date of Award

12-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical and Civil Engineering

First Advisor

Razvan Rusovici

Second Advisor

Ilya Mingareev

Third Advisor

Gerald J. Micklow

Fourth Advisor

James R. Brenner

Abstract

Background: The current study investigates if tympanic (myringotomy) tubes affect hearing by comparing the harmonic displacement response to sound excitation within the hearing frequency range for healthy vs. surgically-treated pediatric tympanic membranes. The use of ear myringotomy tubes has proven an effective method for combating recurrent ear infections in infants and children. These tubes are placed in the tympanic membrane through an incision and connect the middle ear to the external ear, thereby allowing fluid drainage and middle-ear ventilation. While this treatment has been proven beneficial in alleviating urgent pus accumulation in the middle ear, recent research shows that it may induce long-term adverse effects, such as partial hearing loss and permanent tympanic membrane injury. Methods: The studies were conducted using the finite element (FE) method through the development of a model of a pediatric tympanic membrane and middle ear cavity, which was then analyzed and calibrated according to results found in published literature. These analyses included harmonic and modal studies that compared acoustic and structural modal distributions, as well as displacement and pressure responses to published results. Results: The subsequent studies conducted on a calibrated finite element model (FEM) show a significant change in the tympanic membrane’s displacement frequency response, in both amplitude and frequency distribution due to the added tube mass and change in the surgically incised tympanic membrane. Conclusions: Myringotomy tubes may impact both short-term and long-term hearing, which could lead to developmental delays, particularly in toddlers developing speech.

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