Dynamic glottal pressures in an excised hemilarynx model.

Area of Science:

• Laryngology
• Bioacoustics
• Biomechanics

Background:

• Phonation relies on air pressures to sustain vocal fold oscillation.
• Dynamic pressure variations along the vocal folds are critical but poorly understood in real-time.
• Previous studies lacked live or excised human data on time-dependent glottal pressure profiles.

Purpose of the Study:

• To investigate time-dependent glottal pressure profiles.
• To analyze pressure variations using a canine hemilarynx model.
• To understand the relationship between pressure gradients and vocal fold mechanics.

Main Methods:

• Utilized a canine hemilarynx model with a Plexiglas insert and pressure taps.
• Recorded simultaneous glottal pressure, subglottal pressure, particle velocity, and airflow.
• Examined pressure variations at different levels of vocal fold adduction.

Main Results:

• Glottal pressures exhibit significant vertical and longitudinal variations throughout the phonatory cycle.
• Pressures fluctuate most near the maximum vibratory amplitude, including transient negative pressures.
• Areas anterior and posterior to maximum vibration show less variation and sustained positive pressures, defining dynamic bidirectional pressure gradients.

Conclusions:

• Dynamic bidirectional pressure gradients in the glottis are identified.
• These pressure gradients are integral to vocal fold oscillatory mechanics.
• Understanding these pressures may be key to vocal fold tissue health and injury prevention.