A Systematic Review of Voice Therapy: What "Effectiveness" Really Implies

Behavioral voice therapy guided by a speech-language pathologist is recommended as the main treatment approach for many kinds of voice disorders. Encouraging evidence regard of good outcomes from voice therapy has been found in two previous reviews on broad patient populations. However, no definitive conclusion on the effectiveness of direct voice therapy can be drawn from these reviews due to limitations of the included studies.

To review recent literature on voice therapy; to provide clinicians with a list of evidence-based voice therapy techniques; to incorporate the therapy components in a physiologically based model; to assess the limitations and progress achieved in the recent research on voice therapy.

A literature search was conducted using three electronic databases: PubMed, Scopus, and CINAHL. A similar strategy was used in all three databases to highlight the concepts of "therapy" and "voice disorders." Only randomized controlled trials were included in the review.

Fifteen papers met the inclusion criteria, covering five categories of voice disorders (functional, Parkinson induced, GERD induced, presbyphonia, unilateral vocal fold paresis) and seven specific behavioral voice therapy approaches. Statistically significant improvements were found postintervention on at least one outcome variable in all but one study. Clinical significance of the results was rarely discussed. Discrepancies in reported outcome measures were found across studies, making comparisons between interventions challenging.

Behavioral voice therapy generally leads to significant improvements in voice outcomes, but further research considering clinical meaningfulness of the results are needed to establish what is really meant by the term "effectiveness" when it comes to voice therapy.