Systematic review and meta-analysis of studies on voice outcomes following straw phonation exercise for individuals with functional dysphonia

Abstract

Objectives: The aim of the present study was to systematically evaluate the evidence on the effectiveness of straw phonation exercise for treatment of functional dysphonia. Methods: Nine electronic databases were searched to identify outcome studies that used straw phonation exercise for treating functional dysphonia. The Critical Appraisal of Treatment Evidence (CATE) checklist was used to assess the qualities of all included studies by two independent reviewers. Results from selected outcomes are synthesized according to parameters. For studies with comparable data, meta-analyses were performed. Results: Five studies were included for data synthesis, and among them four were included for meta-analysis. Straw phonation was found to bring significant improvements in all subjective but only in some objective outcome measures. The influence of straw diameters on treatment outcomes could not be explored due to insufficient data. Validity of results were weakened by the methodological defects of all included studies. Conclusion: Preliminary evidence supports the use of straw phonation exercise as an effective intervention to improve voice outcomes for individuals with functional dysphonia. The results suggest the need for more intervention studies with rigorous study designs to support the use of straw phonation exercise in voice treatment.