The Impact of Semi-Occluded Vocal Tract Exercises on Multidimensional Measures of Voice in Dysphonia: A Randomized Controlled Study.

PURPOSE: The data on the effectiveness of the semi-occluded vocal tract exercise (SOVTE) program over multiple sessions are not yet sufficiently documented, and there is a need for future research within structured therapeutic frameworks. Investigating therapeutic techniques within a treatment paradigm may help to evaluate the long-term effectiveness and better management of voice disorders.

STUDY

DESIGN

The design of this study was a prospective, single-blind, randomized controlled trial.

METHOD: The study was a four-arm trial-(a) lip trill group-experimental group 1, (b) straw phonation group-experimental group 2, (c) vocal function exercises group-experimental group 3, or (d) no-treatment group (NT). The study included 44 participants who were diagnosed with voice disorder secondary to organic causes. Outcome measures were obtained after 6 voice therapy sessions of 30-40 minutes each, carried out twice weekly for the 3 experimental groups. Independent practice at home was used as well. The subjective, objective, and multiparametric measures of voice were analyzed.

RESULTS

Linear mixed-model analyses revealed significant effects of Conditions and Groups, confirming treatment efficacy. Repeated measures analysis of variance also showed strong conditions effects. In posttreatment, the values of the subjective parameters (Grade, Roughness, Breathiness, Asthenia, Strain, and the scores of the Vocal Performance Questionnaire) were reduced; the values of acoustic and multiparametric measures such as jitter, shimmer, Acoustic Voice Quality Index, and Acoustic Breathiness Index scores reduced and the smoothed cepstral peak prominence values increased; and the perturbation-related electroglottographic parameters reduced in all experimental groups. Post hoc tests confirmed significantly better outcomes in experimental groups versus the NT, and the lip trill group showed better improvements among all the experimental groups.

CONCLUSION

The results confirmed that all three SOVTEs caused significant improvements in the outcome measures in individuals with dysphonia compared with the NT.

TRIAL REGISTRATION: Clinical Trials Registry-India (CTRI/2023/09/057396).