The effectiveness of voice hygiene and practical training for preschool teachers in Bosnia and Herzegovina.

Effective voice education promotes healthy voice use, particularly for kindergarten teachers in demanding environments. This study assessed the effectiveness of a brief, workplace-based voice education program for the preschool teachers. Teachers were quasi-randomly assigned based on work schedules to either the Direct Voice Training Group (N = 31), which received a four-hour face-to-face training session and an educational booklet, or the Educational Booklet Only Group (N = 45). Outcomes were measured using the Vocal Fatigue Index (VFI) and blinded perceptual voice quality assessments via the GRBAS scale at baseline and three months post-intervention. Nonparametric Wilcoxon signed-rank tests assessed statistical significance, with effect sizes (r) calculated. Both groups improved significantly, but the Direct Voice Training Group showed broader improvements, with small to medium effect sizes (r = 0.25-0.38), whereas the Booklet Only Group had limited improvements (r < 0.3). Blinded evaluations confirmed greater benefits for the direct training group. These findings highlight the value of brief, targeted interventions for occupational vocal health, though small to medium effect sizes suggest that more intensive interventions may be required for clinically significant outcomes.