Which teachers are most at risk for voice disorders? Individual factors predicting vocal acoustic parameters monitored in situ during a workweek

Abstract

To identify the factors affecting teachers’ vocal acoustic parameters, with the aim of detecting individuals at risk of phonotrauma. The voicing time, voice sound pressure level [SPL] and fundamental frequency [fo] of 87 teachers were measured during one workweek using a voice dosimeter. We retrospectively investigated the impact of 10 factors (gender, age, teaching experience, teaching level, tobacco, gastro-esophageal problems, nonoccupational voice activity, voice education, past voice problems, and biopsychosocial impact of voice problems measured using the Voice Handicap Index [VHI]) on each voice parameter. None of the above factors affected voicing time or SPL. fo depended significantly on gender, teaching level, nonoccupational voice activity and VHI score. Specifically, fo was higher in women (Δ\u2009=\u200969 Hz), in individuals without nonoccupational voice activities (Δ\u2009=\u200911 Hz), and in individuals with a lower VHI score (increase of 0.7 Hz for each additional point). For females, post hoc comparisons revealed a substantial impact of teaching level on fo: university instructors had deeper voices than kindergarten (Δ\u2009=\u200966 Hz), elementary (Δ\u2009=\u200952 Hz), or secondary teachers (Δ\u2009=\u200941 Hz). Since higher fo increases the mechanical stress related to vocal fold vibration, the screening and prevention of phonotrauma should focus primarily on women, particularly those who teach at lower levels, and teachers with more self-rated voice problems. The lower fo of teachers who engage in nonprofessional voice activities may suggest acute inflammation or muscle fatigue due to voice overload.