Multiparametric and Cepstral Measures in Teachers Without Laryngeal Alterations: Comparison by Sex and Degree of Vocal Deviation.

OBJECTIVE

To analyze multiparametric acoustic indices (Acoustic Voice Quality Index [AVQI], Acoustic Breathiness Index [ABI], and Dysphonia Severity Index [DSI]) and cepstral peak prominence (CPP) and smoothed cepstral peak prominence (CPPS) measures according to sex and vocal quality in male and female teachers with normal laryngeal function. This analysis aims to deepen our understanding of these measures and their application in vocal assessments.

METHODS

This cross-sectional observational study included 86 teachers without laryngeal disorders (48 females and 38 males) aged 23-55 years, recruited from the Superintendência Central de Perícia Médica e Saúde Ocupacional, Minas Gerais, Brazil. The participants included teachers with normal laryngeal examinations. The exclusion criteria comprised smoking, active allergies/colds during recording, pregnancy or menstruation (for women), and functional dysphonia (muscle tension dysphonia, pressed/strained phonation), as determined by three speech-language pathologists' independent perceptual evaluations. Acoustic assessment was performed using sustained vowels, connected speech, and specific phonation tasks in the study. Multiparametric indices (AVQI, ABI, and DSI) and cepstral measures (CPP and CPPS) were extracted using Praat software. Voice samples (sustained vowel [a] and counting 1-20) were perceptually evaluated by three speech therapists using the GRBASI scale's G parameter (0-3 scale), showing substantial inter-rater agreement. Statistical analyses included the Mann-Whitney and t tests with a 95% confidence level.

RESULTS

Significant differences were observed among female teachers: those with normal voice quality (G0) showed higher DSI and CPP (in continuous speech) than those with mildly deviant voices (G1). In the sex-based comparison, women had higher ABI values than men in the G0 group, and higher AVQI and ABI scores in the G1 group. For cepstral measures, only the CPP in continuous speech differed significantly between the sexes, with higher values in women with G0.

CONCLUSION

The results demonstrate that both voice quality and biological sex influence acoustic voice parameters. These findings highlight the importance of incorporating these measures into the evaluation of vocal quality and support the need for sex-specific reference values in vocally demanding professions such as teaching.