RESUMO
INTRODUCTION: Teachers seem to be vulnerable to voice disorders because of excessive use of their voice. The purpose of this study was to investigate the effects of a voice education program on the Vocal Handicap Index (VHI) scores of elementary school teachers in the Persian education system. METHOD: This was a semi-experimental study, performed in Shiraz public schools. Ten schools were selected on their similarity in number of students and teachers, and allocated at random to training or control groups. Sixty-one teachers in the training group and 66 teachers in the control group completed the VHI in the first week. Teachers in the trained group received voice education for 4 weeks, and then continued to follow the program for a further 4 weeks. The control group received no training. After 8 weeks, all subjects completed the questionnaire again. RESULTS: Compliance was good for all practices except "breathing exercises" and "using amplifiers" where it was exceptionally poor. Teachers in the training group improved significantly in total VHI score (from 14.2 to 6.8), whereas the control group showed a significant worsening (from 10.1 to 13.7). These effects were significant (P < 0.05) for total VHI score and for all subscales. The corresponding effect sizes for the training group range from -0.53 to -0.84 (-0.83 in the overall VHI). CONCLUSION: A voice education program can have positive effects on the voice of teachers, even without dysphonia, in the middle of their teaching. Such a program may have a place in the Persian education system.