A two-dimensional biomechanical model of vocal fold posturing.

Area of Science:

• Biomechanics
• Speech Science
• Computational Modeling

Background:

• Understanding laryngeal cartilage dynamics is crucial for voice production.
• Quantifying forces and torques in 2D laryngeal movement provides insight into vocal fold function.

Purpose of the Study:

• To quantify the forces and torques governing two-dimensional (2D) translation and rotation of laryngeal cartilages.
• To model vocal fold posturing (elongation and adduction) based on intrinsic laryngeal muscle activations.
• To compare simulated and measured movement and acoustic outputs for a repeated /hi/ gesture.

Main Methods:

• Developed a computational model of the larynx, incorporating three-dimensional (3D) cartilage movements.
• Programmed activations of five intrinsic laryngeal muscles (cricothyroid, thyroarytenoid, lateral cricoarytenoid, posterior cricoarytenoid, interarytenoid) as inputs.
• Utilized measured electromyographic signals as inputs for modeling a repeated adductory-abductory gesture (/hi-hi-hi-hi-hi/).
• Quantified muscle parameters including maximum active stress, passive stress, activation time, contraction time, and maximum shortening velocity.

Main Results:

• The model successfully simulated the dynamics of 2D laryngeal posturing based on muscle activations.
• Comparison between simulated and measured movement and acoustic outputs for the /hi/ gesture showed agreement.
• The study effectively quantified the forces and torques involved in laryngeal cartilage motion.

Conclusions:

• The developed model accurately simulates laryngeal dynamics and vocal fold posturing.
• Computational modeling with electromyographic inputs provides a valid approach to studying voice production.
• This research enhances our understanding of the biomechanical principles underlying speech production.