Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Area of Science:

• Biomechanics of speech
• Vocal fold dynamics
• Laryngeal physiology

Background:

• Understanding vocal fold dynamics is crucial for diagnosing and treating voice disorders.
• Ex-vivo hemilarynx experiments provide a controlled environment to study phonation mechanisms.

Purpose of the Study:

• To investigate the impact of vocal fold adduction on vibrational output, glottal flow resistance, and sound pressure.
• To analyze the relationship between adduction, airflow dynamics, and vocal fold oscillation patterns.

Main Methods:

• Experiments were conducted on three excised human male larynges.
• Measurements included vibrational output, glottal flow resistance, and sound pressure.
• Analysis involved empirical eigenfunctions, displacements, and velocities along the vocal fold surface.

Main Results:

• Increased adduction raised glottal flow resistance and oscillation amplitudes in two larynges, suggesting improved energy transfer.
• One larynx showed decreased resistance and amplitude with increased adduction, linked to unbalanced, predominantly lateral oscillations.
• Balanced vertical-lateral oscillation patterns were found to be more beneficial for phonation than predominantly lateral vibrations.

Conclusions:

• Vocal fold adduction can facilitate phonation by increasing resistance and enhancing vibrations, but requires a balanced vertical-lateral displacement ratio.
• An unbalanced oscillation pattern, even with increased adduction, can negatively impact phonation.
• The findings highlight the importance of balanced vocal fold dynamics for efficient voice production.