Vocal load investigations on primary school teachers

Statistics on professional figures with diseases related to the phonatory apparatus show the need for an immediate investigation. Vocal emission is influenced to a great extent by the acoustic conditions of the workplace and by some other physiological and psychological factors. Teachers, of different types and levels, including teachers of physical education and music, are one of the most affected categories of work types. In a similar way to the hearing field, literature suggests the use of a dosimetry to measure the vocal load, a field that has not yet been fully explored. The Ambulatory Phonation Monitor (APM3200) is a portable device that consists of an accelerometer positioned on the talker's neck, and worn over an entire working day, provides the phonation time, the fundamental frequency and the sound pressure level, estimated 12 cm from the speaker's mouth, after a calibration. Some vocal dose measures, such as the Vocal Loading Index, the Time Dose, the Distance Dose, the Energy Dissipated Dose and the Energy Radiated Dose, can be determined from the above vocal parameters. In this work the results of a survey that were carried out in six primary schools in Turin and Beinasco (Italy) are presented. In particular, the vocal parameters and vocal doses related to the primary school teachers measured over some working days have been correlated with the subjective assessments of vocal load and performance, the background noise level and the reverberation time measured in the classrooms.