Connections between voice ergonomic risk factors in classrooms and teachers' voice production.

Objective: The aim of the study was to investigate if voice ergonomic risk factors in classrooms correlated with acoustic parameters of teachers' voice production.
Methods: The voice ergonomic risk factors in the fields of working culture, working postures and indoor air quality were assessed in 40 classrooms using the Voice Ergonomic Assessment in Work Environment - Handbook and Checklist. Teachers (32 females, 8 males) from the above-mentioned classrooms recorded text readings before and after a working day. Fundamental frequency, sound pressure level (SPL) and the slope of the spectrum (alpha ratio) were analyzed.
Results: The higher the number of the risk factors in the classrooms, the higher SPL the teachers used and the more strained the males' voices (increased alpha ratio) were. The SPL was already higher before the working day in the teachers with higher risk than in those with lower risk.
Conclusion: In the working environment with many voice ergonomic risk factors, speakers increase voice loudness and use more strained voice quality (males). A practical implication of the results is that voice ergonomic assessments are needed in schools.
(Copyright © 2013 S. Karger AG, Basel.)