Short-Term Effects of Four Common Semioccluded Vocal Tract Exercises in Primary Muscle Tension Dysphonia: A Randomized Controlled Trial.

OBJECTIVES

This study investigated the effects of four common semioccluded vocal tract exercises (SOVTEs)-tongue trill, lip trill, straw phonation, and water resistance therapy (WRT)-in primary muscle tension dysphonia (MTD).

STUDY

DESIGN

Double-blind randomized controlled trial.

METHODS

The participants who included 30 females with primary MTD were randomly assigned to one of four experimental SOVTE groups and a vocal hygiene (control) group. Each participant underwent four voice therapy sessions, conducted twice weekly. Aerodynamic, acoustic, auditory-perceptual, and self-assessments were performed before and after the interventions.

RESULTS

Within-group comparisons indicated a significant improvement in maximum phonation time (MPT) following lip trill, straw phonation, and WRT (P < 0.05). No significant changes were observed for acoustic measures in SOVTE groups (P > 0.05). The overall severity of dysphonia significantly decreased after tongue trill and straw phonation. Frequency and severity of vocal tract discomfort (VTD) and the voice handicap index (VHI) showed significant improvements after straw phonation and WRT (p< 0.05). In the control group, only acoustic measures and VHI changed significantly (P < 0.05). Between-group comparisons revealed significant improvement only in the MPT and VTD. Post hoc analyses demonstrated that MPT improvement was significantly greater in the straw phonation compared with other groups (P < 0.05; η² ≥ 0.14). Additionally, significant differences were observed between trills, tongue trill and WRT, and WRT and vocal hygiene for the VTD (P > 0.05; η² ≥ 0.14).

CONCLUSION

All SOVTEs were effective in primary MTD. Although certain SOVTEs demonstrated significant improvements in MPT and VTD, no single exercise was identified as the most beneficial. Future studies with larger sample size and objective measures are recommended.