Vocal Training in Healthy Individuals: A Scoping Review

Abstract

This study aimed to map the characteristics and effects of vocal training approaches in individuals with healthy voice. This is a scoping review based on three research questions: What are the interventions used for vocal training of individuals with healthy voice? What are their prescription parameters? What are their effects? The search was conducted electronically in the databases of Embase, Lilacs, Medline, Scopus, and Web of Science. The study selection was based on the reading of titles, abstracts, and full text, applying the eligibility criteria. Data related to the characteristics of the publication, sample, and intervention were extracted. Measures/outcomes and results were also extracted. Quantitative synthesis was performed, and the results were presented in descriptive format. In total, 221 studies were identified during the search, of which 23 were selected. The most frequently used approach in the vocal training of individuals with healthy voice was the Semi-Occluded Vocal Tract Exercise (SOVTE), mainly with tube and straw phonation. Many studies have focused on the immediate effect, with varying dosages. The main outcome measures were acoustic analysis, aerodynamic evaluation, electroglotography, and vocal self-assessment. Positive effects were mainly observed on aerodynamic and acoustic parameters. Only one study reported negative results in the self-assessment. The SOVTE is most frequently performed to provide an immediate effect in the acoustic analysis and has also demonstrated positive effects on vocal self-assessment. Medium and long-term effects and dosages are rarely reported and should be also investigated.