ABSTRACT
BACKGROUND AND OBJECTIVES: Many patients who have voice disorders simply use too much effort and strain when they speak or sing and create too much laryngeal muscle tension. Therefore voice therapy have been a viable adjunct to surgery and pharmachological therapy for the management of voice disorder. No definitive data exist about the efficacy of techniques used in voice therapy. Moreover, aerodynamic and acoustic analysis according to respiration and phonation methods has seldom been reported. MATERIALS AND METHODS: In this study, healthy adults with natural breathing, abdominal breathing, and abdominal breathing with resonant phonation were analysed by aerodynamic and acoustic method. RESULTS: In the order of natural breathing, abdominal breathing, and abdominal breathing with resonant phonation, maximum phonation tended to increase, but without statistical significance. In both sex, the fundamental frequency, mean airflow rate, intensity tended to increase and glottal resistance tended to decrease at abdominal breathing and abdominal breathing with resonant phonation than natural breathing, but without statistical significance, except in easy voice. In female, jitter and shimmer were decreased and NHR was increased at abdominal breathing with resonant phonation and the improvement of acoustic aspects was significant. CONCLUSION: A change of mode of respiration and phonation which inspire more air and control subglottal pressure properly was found to reduce the glottal adduction and increase the vocal efficiency. This respiration and phonation method appear to enhance normal vocal function especially in female who is apt to have more voice disorders than male.