Interaction between epilaryngeal and laryngeal adjustments in regulating vocal fold contact pressure.

Zhaoyan Zhang

doi:10.1121/10.0003393

Abstract

This study investigates the peak vocal fold contact pressure at different conditions of epilaryngeal narrowing and laryngeal adjustments. The results show that for a given subglottal pressure, the peak vocal fold contact pressure may increase or decrease with epilaryngeal narrowing, depending on a complex interaction between vocal fold vertical thickness, initial glottal angle, and subglottal pressure. However, epilaryngeal narrowing also significantly increases vocal efficiency so that for a target sound pressure level, the peak vocal fold contact pressure decreases with epilaryngeal narrowing. Overall, the peak vocal fold contact pressure and respiratory effort can be minimized by epilaryngeal narrowing, adopting a small initial glottal angle, and an intermediate vocal fold thickness.

Highlights

This study aims to better understand the effect of epilaryngeal narrowing on the peak contact pressure between the vocal folds during phonation, an important contributing factor to vocal fold injury
This study shows that for a given constant subglottal pressure, while epilaryngeal narrowing consistently increases sound pressure level (SPL), its effect on the peak vocal fold contact pressure is variable and depends on a complex interaction between the vertical thickness, initial glottal angle, and subglottal pressure
For thin vocal folds or low to moderate subglottal pressures, the peak contact pressure generally increases with increasing epilaryngeal narrowing at small initial glottal angles

Summary

Introduction

This study aims to better understand the effect of epilaryngeal narrowing on the peak contact pressure between the vocal folds during phonation, an important contributing factor to vocal fold injury. Epilaryngeal narrowing and other similar vocal tract adjustments have been widely used in vocal training and voice therapy (e.g., resonant voice therapy or semi-occluded phonation, Verdolini-Marston et al, 1995; Verdolini et al, 1998; Titze, 2006), with one important goal being to minimize vocal fold contact pressure. It was pointed out that this effect would depend on the interaction between the degrees of epilaryngeal narrowing and vocal fold adduction This study investigates this interaction between epilaryngeal narrowing and laryngeal adjustments in controlling the peak vocal fold contact pressure between the vocal folds. The specific goal is to determine the epilaryngeal and laryngeal conditions that produce the lowest peak vocal fold contact pressure in voice tasks either with a given constant subglottal pressure or targeting a specific sound pressure level (SPL)

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Conclusion