Cross-Sectional Area and Length Changes With a Semi-Occluded Vocal Tract: The Role of the Epilarynx in Human Phonation

Abstract

The configuration of the vocal tract acoustically transforms the sound produced by the vibration of the vocal folds into the vowels and consonants listeners recognize as speech or song. Although the phonetic components of speech are well known to be produced by modulating the vocal tract with expansions and constrictions, the focus of this study was on understanding how specific types of vocalizations targeted to enhance voice quality generate refinements of the vocal tract shape through further selective widening (expansions/lengthening) and narrowing (constrictions/contractions).Positioned between the vocal folds (source) and vocal tract (filter), the epilarynx has been proposed to play a critical role in vowel identity and voice quality. Yet, the physiological changes or series of modifications that take place in this region during specific types of vocalization are not well understood. The purpose of this study was to provide a better understanding of vocal tract shapes across several voicing profiles, commonly used during clinical interventions for the treatment of voice disorders, by quantifying them using high-resolution magnetic resonance imaging (MRI).