OBJECTIVE: To evaluate the effects of using respiratory biofeedback associated with a quiet breathing pattern, on chest circumference, pulmonary function, respiratory muscle strength and the following functional mouth-breathing habits: watching things with mouth open, sleeping with mouth open, dribbling on the pillow, difficulty in waking up, snoring and restlessness during sleep. METHOD: Twenty functional mouth-breathing children were evaluated. They underwent 15 sessions of respiratory biofeedback by means of the biofeedback pletsmovent (MICROHARD® V1.0), which provided biofeedback on thoracoabdominal movements. Chest circumference, spirometry and maximum static respiratory pressures were determined before and after the therapy. The adults responsible for these children were asked questions about the children's mouth-breathing habits. Student's t test for paired data and non-parametric tests were used to analyze the data. RESULTS: The use of respiratory biofeedback in association with a quiet breathing pattern did not produce significant alterations in chest circumference or in forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), Tiffeneau index (TI) or maximal expiratory pressure (MEP). However, there was a significant difference in maximal inspiratory pressure (MIP) (-53.6 ± 2.9 cmH2O vs. -65.0 ± 6.0 cmH2O; p< 0.05) and there were significant changes in the evaluated habits. CONCLUSION: The results allow the conclusion that respiratory biofeedback associated with a quiet breathing pattern improves the inspiratory muscle strength and habits of functional mouth-breathers. It can therefore be used as a therapeutic method for such individuals.
mouth breathing; physical therapy; respiration
