Vocal tract physiology and its MRI evaluation

Abstract

Introduction. The rapid technological evolution in Magnetic Resonance Imaging (MRI) has recently offered a great opportunity for the analysis of voice production. Objectives. This article is aimed to describe main physiological principles at the base of voice production (in particular of vocal tract), and an overview about literature on MRI of the vocal tract. This is presented in order to analyze both present results and future perspectives. Method. A narrative review was performed by searching the MeSH terms “vocal tract” and “MRI” in PubMed database. Then, the obtained studies were subsequently selected by relevancy. Results. Main fields described in literature concern technical feasibility and optimization of MRI sequences, modifications of vocal tract in vowel or articulatory phonetics, modifications of vocal tract in singing, 3D reproduction of vocal tract and segmentation, and describing vocal tract in pathological conditions. Conclusions. MRI is potentially the best method to study the vocal tract physiology during voice production. Most recent studies have achieved good results in representation of changes in the vocal tract during emission of vowels and singing. Further developments in MR technique are necessary to allow an equally detailed study of faster movements that participate in the articulation of speaking, which will allow fascinating perspectives in clinical use.