Importance: Few studies have evaluated the pediatric voice objectively using acoustic measurements. Furthermore, consistency of these measurements across time, particularly for continuous speech, has not been evaluated.
Objectives: (1) To evaluate normal pediatric voice frequency and perturbation using both time-based and frequency-based acoustic measurements, and (2) to determine if continuous speech samples facilitate increased recording stability. DESIGN Prospective, longitudinal study.
Setting: Pediatric otolaryngology practice within a tertiary hospital.
Participants: Forty-three children, ages 4 to 17 years. INTERVENTION OR EXPOSURE: Sustained vowel utterances and continuous speech samples, which included 4 Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) sentences and the first sentence of the "rainbow passage" ("A rainbow is a division of white light into many beautiful colors that takes the shape of a long round arch, with its path high above and its 2 ends apparently beyond the horizon") were obtained at 2 time points.
Main outcome and measure: Intraclass correlation coefficients (ICCs) were calculated to assess reliability between speech samples.
Results: Fundamental frequency of sustained vowel utterances had excellent reliability (ICC ≥ 0.94). Time-based analyses of perturbation in sustained vowel utterances demonstrated poor reliability (ICC < 0.40), while frequency-based analyses of perturbation for these utterances demonstrated good to excellent reliability (ICC > 0.40). Fundamental frequency of continuous speech sample had excellent reliability (ICC > 0.94). Frequency-based analyses of continuous speech samples demonstrated excellent reliability (ICC > 0.75) for all but 1 variable, which demonstrated good reliability (cepstral-spectral index of dysphonia of the all voiced sample; ICC =0.72).
Conclusions and relevance: Sustained vowel utterance and continuous speech samples provide consistent measures of fundamental frequency. Frequency-based analysis of sustained vowel recordings improves the reliability of perturbation measures. Continuous speech recordings can be obtained in children and demonstrate good to excellent reliability across recordings. This suggests that frequency-based analysis of continuous speech may be more representative of a child's voice and therefore may be of use in the study both of the developmental changes of the pediatric voice as well as the study of vocal changes pretreatment and posttreatment in children with voice disorders.