Vocal characteristics of 5-year-old children: proposed normative values based on a French-speaking population†

Purpose: Previous research proposed normative data on gender- and age-specific voice acoustics for adults. Such reference values are lacking for children, particularly under the age of 6. This study was intended (1) to collect reliable normative data for the acoustic parameters of 5-year-old children's voices, and (2) to investigate potential gender-specific differences. Study: Prospective and cross-sectional. Methods: Acoustic analyses were done on the voices of 53 normophonic children (26 girls; 27 boys) aged 5;0-5;11 years, using Praat software. The fundamental frequency, local jitter, local shimmer, and noise-to-harmonics ratio (NHR) were measured on the sustained vowels [a], [i], and [u]. The highest frequency, lowest frequency, and frequency range were measured using ascending and descending glissandi on the vowel [a]. Results: For the three sustained vowels, the mean fundamental frequency ranged from 255 Hz to 277 Hz, mean jitter ranged from 0.394% to 0.591%, mean shimmer ranged from 2.571% to 5.824%, and mean NHR ranged from 0.009 to 0.034. The frequency range was from 190 Hz to 750 Hz, which corresponds to 23.7 semitones. No gender difference was found, except for NHR on the vowel [a]. Conclusions: The lack of gender differences - other than for NHR on the vowel [a] - led us to propose mixed norms for 5-year-old boys and girls combined. Implications: These normative data will allow clinicians to compare children's voice assessments to specific references in order to enhance diagnostic accuracy and measure therapy outcomes.