Effects of Sulcus Vocalis Depth on Phonation in Three-Dimensional Fluid-Structure Interaction Laryngeal Models

Area of Science:

• Biomechanics
• Vocal Fold Physiology
• Computational Fluid Dynamics

Background:

• Sulcus vocalis is a vocal fold indentation affecting phonation.
• Understanding the impact of sulcus depth on vocal fold function is crucial.

Purpose of the Study:

• To investigate the effects of sulcus vocalis depth on phonation and vocal fold vibration.
• To establish numerical models simulating vocal fold dynamics with varying sulcus depths.

Main Methods:

• Three-dimensional laryngeal models were created for healthy and sulcus vocalis conditions (1-3mm depth).
• Fluid-structure interaction (FSI) was computed using sequential coupling: immersed boundary method (IBM) for airflow and finite-element method (FEM) for tissue.
• Numerical simulations analyzed vocal fold vibration and airflow dynamics.

Main Results:

• Increased sulcus vocalis depth reduced vocal fold vibrating frequency.
• Deeper sulcus vocalis expanded prephonatory glottal half-width, increasing phonation threshold pressure.
• Vocal fold vibration and phonation became more difficult with greater sulcus depth.

Conclusions:

• Sulcus vocalis depth significantly impacts vocal fold vibration and phonation.
• Phonation threshold pressure can serve as a diagnostic indicator for healthy vocal folds and different sulcus vocalis types.
• These findings contribute to understanding vocal fold pathologies and developing diagnostic tools.