A systematic review of resonant voice therapy

Abstract

Purpose 1) To provide a systematic guideline on the contents of resonant voice therapy in terms of definition, variety of resonant voice therapy and the therapeutic steps involved. 2) To evaluate the level of evidence of the effectiveness of using resonant voice therapy in treating voice disorders. Method Refereed journal papers between the years 1974 to 2014 were searched using the keywords “Humming, Resonant Voice Therapy, Resonant Voice” through data- base Elsevier ScienceDirect Complete, Medline & Proquest Medical Library New Platform. Quality of evidence was evaluated by using The GRADE Approach by students. Result Nine studies met the search criteria. Only one was a randomized- controlled study and the other eight were observational studies. Types of resonant voice therapies commonly mentioned in the studies include Lessac- Madsen Resonant Voice Therapy, Y- Buzz, resonance therapy and humming. Overall level of quality of evidence was graded as “low”. Conclusion There were limited studies that investigated the effectiveness of Resonant Voice Therapy. Most studies were small- scaled uncontrolled observational studies with the inclusion of only narrow populations. There is clearly a need for more large-scale randomized controlled studies with wider population to provide further evidence for the effectiveness of resonant voice training.