Numerical Investigations of Pathological Phonation Resulting From a Unilateral Sessile Polyp

The voice, generated via the modulation of airflow by the vocal folds in the larynx, is studied computationally to improve treatment of voice disorders. A model of a vocal fold with a polyp is developed, and implemented in-house. Structural vibration of the model is computed in the time and frequency domain with the finite element method. Aerodynamic loading is computed with the Bernoulli equation, which is corrected for viscous and unsteady effects. A polyp’s mass is the most influential parameter, followed by stiffness and position. Natural frequencies are decreased by increasing mass, and increased by increasing stiffness. Damping due to the polyp’s mass is mitigated near fixed walls. Polyp mass distribution is most influential on vibration when spread into the glottis. Pitch-intensity dependence decreases with increasing polyp mass. The polyp disrupts vibration of the vocal fold pair by decreasing the cross-sectional area of the flow, and vibrating out of phase.