Immediate effect of two semi-occluded vocal tract exercises in glottal contact of occupational voice users

Abstract

Introduction. Teachers are occupational voice users with high risk of developing vocal pathologies due to their work. To face this situation, it is common the use of semi-occluded vocal tract (SOVT) exercises, a strategy of voice education/rehabil-itation implemented to induce a change in the vibration pattern of the vocal folds, mitigating, therefore, the risk of vocal lesion by reducing the collision stress applied to tissues. A variety of reports have indicated that this treatment has effects in the closed quotient (CQ), an indirect measure of collision stress. Aim. The purpose of this study was to examine the physiological effect of two different SOVT exercises in larynx activity of teachers with constant vocal effort but without vocal pathology. Methods. 43 samples of teachers were recorded before, during and after executing two SOVT exercises (tongue trill and tube phonation). Electroglottographic samples were analyzed in order to obtain CQ. Results and conclusion. Both exercises had a significant difference of CQ scores when before and during conditions were compared. Any difference was found on this parameter after executing the activity. These findings agree with previous reports where CQ tends to increase during phonation through resonance tubes; on the con-trary, execution of tongue trill tends to decrease CQ values. This behavior might be because of the particular biomechanical mechanisms of each exercise.