Effects of Voice Therapy on Muscle Tension Dysphonia: A Systematic Literature Review

The present study aimed to carry out a systematic review of the effects of voice therapy on individuals diagnosed with muscle tension dysphonia (MTD) or hyperfunctional dysphonia. This is a systematic literature review on the databases Medline (via PubMed), Cochrane Library, Scopus, and Lilacs using a search strategy related to the theme of the study. The selection included clinical trials that assessed the effects of speech therapy intervention on patients diagnosed with MTD or hyperfunctional dysphonia published over the last 10 years in Portuguese, English, or Spanish. The Physiotherapy Evidence-Based Database (PEDro) Scale was used to assess the methodology of the studies. Of the 634 publications, 12 studies were included in this review, of which three were excluded due to a low score on the PEDro Scale, resulting in a final number of nine publications. Regarding the techniques approached, semioccluded vocal tract exercises (22.22%), nasal sound and frequency modulation (22.22%), maximum phonation time (MPT) technique and vocal hygiene (11.11%), vocal function exercises (11.11%), respiratory exercises along with phonoarticulatory sounds (11.11%), manual laryngeal therapy (11.11%), and manual laryngeal therapy associated with respiratory exercises (11.11%) were identified. These techniques promoted the following effects: improvement in intraoral and subglottal pressure, positive alterations in the glottal contact quotient, significant changes in fundamental frequency measures, increased MPT, and reduced voice roughness. Methodology was identified to be a shortcoming in the studies. The clinical trials reviewed showed positive results in using the therapeutic techniques selected in the speech therapy approach.