An experimental approach for the evaluation of vocal behavior of university professors

Voice risk factors for teachers were widely investigated, since this professional category is mainly subjected to vocal diseases. However, the existing literature focused on kinder-garden, primary and secondary school-teachers. In this study, the attention is towards the vocal behavior of university professors, who hold lessons in large classrooms, talk continuously for long time intervals and often use microphone to improve their intelligibility. An experimental campaign has been planned that involves subjects that teach in classrooms with different volume, reverberation-time and background-noise. The voice monitoring is performed using Vocal Holter, a portable vocal analyzer developed at Politecnico di Torino. The material collected for each professor includes a sustained vowel /a/, a comfortable free-speech (about five minutes), two lessons (maximum 3 hours). The parameters extracted from the sustained vowel allow a preliminary vocal status of each subject to be assessed, while the free-speech parameters represent the baseline with respect the lesson parameters are compared to. A first pilot study has been carried out that involved 14 subjects that taught in 12 different classrooms. Results are reported in terms of vocal parameters and their correlation to classroom acoustical characteristics. Examples of parameters are jitter, shimmer and CPPS (sustained vowel), sound pressure level, fundamental frequency and duration of voice and silence periods (lessons).