Fundamental Frequency and Formants Before and After Prolonged Voice Use in Teachers.

OBJECTIVES: This study aimed to describe and correlate the fundamental frequency behavior and the first four formants before and after exposure to usual and routinely prolonged voice use from teachers with over 4 years of experience in teaching.

STUDY DESIGN: The study design is observational and transversal with quantitative and descriptive evaluations.

METHODS: A total of 28 female teachers were subjected to the Screening Index for Voice Disorder (SIVD) and to recordings of the sustained vowel /a/ before and after exposure to prolonged voice use. Data were obtained about the fundamental frequency and the first four formants before and after voice use. Descriptive analysis and statistical processing were performed with P ≤ 0.05 for the general sample and in groups according to the outcome of the SIVD (normal and altered) and the evaluation period (morning or afternoon).

RESULTS: The average exposure time to prolonged voice use was 176 minutes. There was no statistical difference in any of the variables studied. Correlations were positive and similar across all assessments before the class, something not observed in evaluations conducted after exposure to prolonged voice use. In the general sample, altered SIVD and afternoon period groups, the second formant from before-class measurements seems to interfere negatively in the fourth formant from after-class measurements.

CONCLUSIONS: There were no changes in vocal behavior before and after exposure to prolonged voice use in the occupational environment. However, formants F1 and F2 measured before class correlated inversely with F4 after exposure to prolonged voice use.