Prevalence of vocal handicap among primary school teachers in Malaysia and validation of a noise-measuring wearable device to measure vocal intensity
Zainal Shaffiq Ahmad Shukkeri, Sheng Qian Yew, Marina Mat Baki, Nor Shahrina Mohd ZawawiIntroduction
The prevalence of vocal handicap among primary school teachers in Malaysia has not been previously investigated, and effective preventive strategies remain lacking. This study aimed to determine the prevalence of vocal handicap among primary school teachers in Negeri Sembilan, Malaysia, and to evaluate the validity and reliability of a wearable device, originally designed for noise measurement, for assessing vocal intensity in this population.
Materials & Methods
The study was conducted in two phases. Phase 1 was a cross-sectional survey using the Malay-Vocal Handicap Index-10 (M-VHI-10) to assess the prevalence of vocal handicap among primary school teachers in Negeri Sembilan, Malaysia. Phase 2 was a cross-sectional validation study in which voice intensity measured by the wearable device was compared with that of a voice dosimeter (gold standard); concurrent validity by Pearson correlation; agreement by intraclass correlation (ICC [3,1]).
Results
A total of 132 (response rate = 92.3%) and 28 (response rate = 100.0%) teachers participated in Phase 1 and Phase 2, respectively. The overall prevalence of vocal handicap was 79.5%, with teachers using voice amplifiers showing a significantly higher prevalence (89.8%) compared to those not using voice amplifiers (73.5%) ( p = 0.025). No significant differences were observed between different school types ( p = 0.105). The wearable device exhibited poor concurrent validity ( r = 0.184, p = 0.330) and poor inter-rater reliability (ICC = 0.077, p = 0.171) in measuring vocal intensity compared with a voice dosimeter (gold standard).
Conclusion
The prevalence of vocal handicap among primary school teachers in Negeri Sembilan, Malaysia, was higher than that reported in other countries. Although it was initially intended to serve as a surrogate instrument for assessing vocal intensity, the wearable device, originally developed for noise measurement, exhibited poor validity and reliability. These findings highlight the need for the development of a novel device specifically designed to measure vocal intensity accurately.