Speaking Fundamental Frequency and Phonation Time during Work and Leisure Time in Vocally Healthy Preschool Teachers Measured with a Voice Accumulator

Abstract

Objective: More knowledge is needed about preschool teachers' voice use to identify voice behaviours related to work demands that increase the risk for vocal dysfunction. The purpose of this study was to: (1) determine if speaking fundamental frequency (F₀) and phonation time differ between work and leisure time and (2) describe variation in F₀ and phonation time across the workday in preschool teachers with healthy voices. Methods: A portable voice accumulator was used to collect data on F₀ and phonation time. Twelve vocally healthy female preschool teachers participated in recordings during both work and leisure time for 2 successive days. Their mean age was 35 years (range 21-53 years). Results: Mean F₀ was high during the working day (266 Hz) and decreased significantly after work (p < 0.0001). F₀ was high also during leisure time (246 Hz) as compared to reference F₀ values for Swedish females based on laboratory recordings. Phonation time at work varied widely among the participants, with an average of 12.0%, and decreased significantly to 5.5% during leisure time (p < 0.0001). Most participants had few opportunities for voice rest during work. Conclusion: Swedish preschool teachers use high levels of F₀ and phonation time during work compared to leisure time indicating high vocal load caused by work. To clarify the role of daily voice use in the causation of vocal dysfunction in this profession, recordings over several days are needed. In addition to F₀ and phonation time, recordings of voice sound pressure level and background noise level seem important.