Acoustic voice and spectrographic measures in children with the phonological process of devoicing

Abstract

IntroductionChildren with speech sound disorders (SSDs) who present the devoicing of plosive and/or fricative sounds may have difficulties with glottal respiratory control. ObjectiveTo analyze acoustic vocal measures, spectrographic aspects and the risk of dysphonia among children with devoicing SDDs and compare the results with those of other groups of children. MethodsTwenty-five boys aged between six and 12 years participated. They were divided into four groups: the SSD-devoicing (PPDG), dysphonia (DG), SSDs other than devoicing (PPOG) and control groups (CG). The vocal tasks were recorded, and perceptual-auditory and acoustic voice analyses were performed. The children's parents answered questions about voice-related aspects (to determine a dysphonia risk score). All data were compared among the groups. ResultsDue to the sample size, an effect size analysis was considered, and the results showed possible differences between the PPDG and the other groups in measures of fundamental frequency (F0), jitter, shimmer, harmonic-to-noise ratio, maximum frequency of harmonic definition and dysphonia risk score. ConclusionsThe PPDG showed a high F0 and abnormal jitter and shimmer values. Although the voices of the children in this group had more harmonics than noise, the maximum frequency for defining the harmonics was very restricted. The PPDG had the lowest dysphonia risk score among all of the groups. Variations in F0, jitter and shimmer may indicate difficulties with controlling vocal adjustments, which appear to be hyperfunctional and not to impact vocal projection or voicing.