Semioccluded Vocal Tract Exercises: Changes in Laryngeal and Pharyngeal Activity During Stroboscopy

Abstract

The purpose of this study was to compare the changes in laryngeal activity from baseline during three different semioccluded vocal tract exercises (SOVTs). This is a prospective case-series study. Transnasal stroboscopy was performed while four singers performed three SOVTs (straw phonation, lip trill, and tongue trill) to evaluate laryngeal changes during the execution of SOVTs. Evaluations using a modified Stroboscopy Evaluation Rating Form captured the following parameters: amplitude of vocal fold movement, mucosal wave, phase closure, glottal closure, anterior-posterior vocal tract constrictions, medial-lateral vocal tract constrictions, laryngeal ascension, and pharyngeal constriction during a pitch glide. The parameters that changed from baseline, as well as the direction and magnitude of change that occurred across SOVTs, varied within and between each subject. All the singers benefited from at least one SOVT, but no single SOVT benefited all four singers. Although SOVTs result in endoscopic and stroboscopic changes that might be considered beneficial, the results indicate marked variability across SOVTs and singers in terms of the laryngeal and pharyngeal adjustments induced by the exercises. Singing teachers and Speech Language Pathologists (SLPs) may need to more carefully assess the impact of specific SOVTs when deciding which one(s) to prescribe as a teaching or therapeutic exercise.