ERI: A Novel Multiphysics Framework for Fluid Circulation and Oxygen Transport in Vocal Folds

Duquesne University, Pittsburgh PA

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Voice disorders have the prevalence of almost 30% in the general population and 60% in professions with high voice usage, such as educators, public speakers, and singers. Most voice dysfunctions have a one-to-one correspondence with the dynamical flow-structure interaction feature of phonation, and localized vocal fold lesions are associated with decreased blood flow and lower oxygen levels within the tissue. There is thus a profound need for understanding the effect of fluid dynamics within the vocal fold on oxygen flow since local changes in tissue oxygenation and perfusion is a critical metric of its functional state. The research results will provide a deep understanding of the fluid physics of phonation and its contribution to hydration and oxygen transport in the vocal fold. The project will also encompass educational plans that involve the operation of a YouTube channel, summer undergraduate research experience, as well as outreach activities to local K-12 schools and the public through the Carnegie Science Center Museum and Women in Science group, through the programs that foster the participation of low-income high school students, K-6 students, and girls in STEM. The goal of this project is to develop a multi-physics computational framework to investigate the role of interstitial liquid distribution and systemic hydration of the vocal fold during phonation using a biphasic description of vocal fold tissue. Systemic hydration plays a key chemo-mechanical role in the function of vocal folds, which is still not fully understood. The project will fill this gap by combining a fluid-poroelastic structure interaction model with an oxygen transport model, in two specific aims: (1) developing a fluid-structure interaction modeling approach integrating the fully coupled behavior between turbulent glottal airflow and porous vocal fold’s structure to provide a spatiotemporal prediction of filtration velocity, as well as oxygen concentration within the porous vocal fold, and (2) investigating the relationship between interstitial fluid circulation and oxygen flow in the vocal fold, in order to identify the extent to which vocal fold dehydration attenuates oxygen concentration. The Reynolds-Averaged Navier-Stokes equations and Biot’s poroelasticity equations are going to be used to model airflow through the larynx and fluid-saturated vocal fold tissue respectively, while for oxygen transport due to the porous flow in the tissue, the convection-diffusion–reaction equation will be applied. The proposed measurements and numeric will quantify for the first time the three-dimensional interstitial convective fluid velocities that drive the mass transport and provide systemic hydration of the tissue, as well as detailed data on oxygen concentration inside the vocal fold under different phonation conditions, that acts as an indicator for tissue hypoxia. Results will highlight the importance of including poroelasticity in phonation models which promotes new visions for the management of vocal diseases, such as in the development of voice prostheses for laryngectomized patients. The findings are also directly applicable to other problems involving fluid-structure interaction and mass transport, such as cardiovascular diseases and tumor metastasis. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.