Smoothed Cepstral Peak Analysis of Brazilian Children and Adolescents Speakers

Childhood and adolescence are essential stages in the development of voice and speech quality; therefore, it is essential to understand the vocal changes that occur during this period. Frequency-based measurement methods like cepstral measurements stand out among the methods described, which are able to identify f_o and estimate the periodicity and noise in the acoustic wave without establishing individual cycles of the sound wave.

Two hundred seventy-one recordings (128 female and 131 male) from children and adolescents aged 5 to 18 years with no vocal complaints were analyzed. Three speech-language pathologists assessed the vocal quality and determined as appropriate for the age. The recordings were divided into six age groups (G1:5-7; G2:8-9; G3:10-11; G4:12; G5:13-15 and G6:16-18 years old). Sustained production of the vowel /a/ were inspected and edited using the PRAAT software. Then, it was extract de Cepstrum Peak Prominence Smoothed (CPPS) using a script in the same software. A Two-way ANOVA was applied to investigate the effect of sex, age and sex*age interaction, followed by Bonferroni's correction for each gender separately. Finally, the Student's t test for independent samples was performed to compare genders within each age group.

Male children and adolescents from G5 and G6 had higher CPPS measures than G1, G2 and G3 (P ≤ 0.001). In addition, G6 also had higher values than G4 (P ≤ 0.001). There was no difference between age groups in the female group. In turn, sex differences were reported from 12 years of age onwards, with higher CPPS values found for male participants compared to female participants (P ≤ 0.01).

Vocal changes that usually occur from childhood to adolescence are reflected in the acoustic CPPS measure in males, resulting in higher values in the 13 to 18 years old. On the other hand, no changes in CPPS values were observed in the age groups of female participants. Males have higher CPPS values than females and that sex differences are reported after 12 years of age.