Presented at the 28th World Congress of the International Association of Logopedics and Phoniatrics, Athens, Greece, 22–26 August 2010

Aim: The present study investigates the differences that may appear on acoustic parameters of the voice in female teachers, as an impact of voice fatigue.
Method: Twenty five female teachers, aged 30 to 45 years, of various specializations were recruited to participate in the study. Teachers, who had previously presented with a voice disorders due to bad vocal behaviour, or teachers, who had temporary voiceness or hoarseness of voice during the study, were excluded. Two vocal samples were selected, the same day from each teacher. The first one was selected early in the morning, before the beginning of teaching and the second in the afternoon, after they had completed their daily teaching hours. Also, during the collection of the data a questionnaire on family, psychosocial and medical history and the history of voice, was completed by all the participants.
The assessment protocol included recorded sample of their voice and speech during the production of phonemes /a/, /s/ and /z/, reading two-syllable words, reading of two texts and spontaneous speech production during a picture description task. The collected data were analyzed with the PRAAT programme.
Results: Analysis and comparison of results, revealed a statistically significant increase in the average fundamental frequency (F₀) of voice and an increase in the first, second and third formants while there were no statistically significant differences in other acoustic parameters of voice.
Discussion: The increase in the average fundamental frequency observed in our subjects indicates a growing strain in vocal folds and the region of the larynx, which is a symptom of vocal fatigue, while the increase in formants may indicates a different placement of the larynx and the articulators, due to vocal fatigue. The implication of teacher’s vocal behaviours on voice will be discussed.