Speech and myofunctional exercise physiology: a critical review of the literature.

PURPOSE: To analyze the scientific literature about the physiology and effects of exercises used in the treatment of oral myofunctional disorders.

RESEARCH STRATEGY: The methodology used followed the concepts of the Cochrane Handbook and involved question formulation related to the topic of investigation, identification and selection of the studies, and a critical evaluation of the selected articles.

SELECTION CRITERIA: Papers were selected on PubMed database using the following keyword combinations: "physiology exercise AND speech, language and hearing science", "exercise physiology AND speech therapy", "exercise physiology AND myofunctional therapy", and "physiology exercise AND swallowing therapy". Only papers written in English and published between the years of 2000 and 2010 were included in the analysis.

DATA ANALYSIS: Manuscripts were analyzed according to their objectives, research design, participants, inclusion of a control group, assessment criteria, therapeutic proposal, results and existence about physiology of the chosen exercises.

RESULTS: One hundred and eight studies were identified, out of which 38 had access to the full text and were directly related to the investigated topic. The articles were classified as clinical trials and experimental research, case studies, literature reviews and theoretical articles, letters to the editor and critical analyses.

CONCLUSION: This review concluded that there is a lack of knowledge about the effects of the myofunctional exercises used by clinicians. Also there is a lack of scientific evidence to determine the frequency at which they should be performed. Generally, the articles investigate the efficacy of treatment programs without inquiring whether the included exercises are individually effective.