Medical Student Research Fellowship for Summer 2010
Mentor: Roger W. Chan, Ph.D., Associate Professor
Department: Otolaryngology-Head and Neck Surgery; Biomedical Engineering
Room number: G7.220A
Mail Code: 9035
Phone number: 214-648-0386
Project title: The effect of subglottal geometry on aerodynamics of the aging voice
Human subjects IRB approved project number (where applicable): not applicable
Animal subjects IRB approved project number (where applicable): not applicable
Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Basic research
Brief Description of Project:
As the U.S. faces a growing aging population in the coming decades, difficulty with communication in the elderly is gaining increased attention in medical research. Recent studies have identified dysphonia in the aging population as a relatively common but under-treated condition. The acoustic and aerodynamic changes associated with the aging voice have been characterized both in the laboratory and clinically. Our research group has added to the theoretical understanding of the aging voice by developing an analytical constitutive model that predicts the age dependence of the fundamental frequency of phonation. We have also collected imaging data on cadaveric larynges of elderly donors to better characterize the anatomical changes that occur with aging.
A new project in our laboratory will test the hypothesis that vocal fold atrophy in the aging larynx could lead to an unfavorable subglottal geometry that results in reduction of aerodynamic energy being transferred to the vocal folds. The modeling component of the project will extract empirical 2D subglottic contours from coronal CT sections of cadaveric larynges. A mathematical model will be developed to quantitatively describe the subglottic geometrical contour, with vocal fold atrophy incorporated as an independent variable. With the model, the pressure drop from the tracheal inlet to the glottis will be computed as a function of the subglottic contour, and compared to pressure profiles for normal voice described in the literature.
The student with an engineering background will play a key role in developing the mathematical model and in applying the model to calculate the effect of subglottic contour on pressure changes in the subglottis. As the empiric imaging data are already available, the summer project will be purely computational in nature. The student will use MATLAB as the primary programming tool to develop and test the model. In addition to being mentored by Dr. Chan, the student will also work closely with Ted Mau, M.D.,Ph.D., Assistant Professor of Otolaryngology and Director of the Voice Center, who collected the cadaveric laryngeal imaging data and will work directly with the student to extract the subglottic contour for the modeling project.
Previous Research Activities or Publications with Medical Students:
Guy Efune, M.D. (Second year resident in Otolaryngology, UTSW) "Acellular scaffolds for vocal fold reconstruction in a rat model", Medical Student Research Project, UTSW (2007).
Lindsay Young, M.D. (Third year resident in Otolaryngology, UTSW) "Relative densities of collagen and elastin in the vocal fold lamina propria", Medical Student Research Project, UTSW (2005-2006).
Sean Callahan, M.D. (Third year resident in Otolaryngology, UTSW) "An analytical review of tensile stress-strain properties of human and animal vocal folds", Medical Student Research Project, UTSW (2005-2006).
Allis Cho, M.D. (Third year resident in Otolaryngology, LSU - Shreveport) "Viscoelastic shear properties of human and animal vocal folds", Medical Student Research Project, UTSW (2005-2006).
Chan, R.W., Fu, M., Young, L., Tirunagari, N. (2007). Relative contributions of collagen and elastin to elasticity of the vocal fold under tension. Annals of Biomedical Engineering, 35, 1471-1483.
Xu, C.C., Chan, R.W., Weinberger, D.G., Efune, G., Pawlowski, K.S. (2010). A bovine acellular scaffold for vocal fold reconstruction in a rat model. Journal of Biomedical Materials Research Part A, 92, 18-32.
Xu, C.C., Chan, R.W., Weinberger, D.G., Efune, G.., Pawlowski, K.S. (2009).
Controlled-release of hepatocyte growth factor from a bovine acellular scaffold
for vocal fold reconstruction. Journal of Biomedical Materials Research Part
A (in press).