Voice quality of children and young people with Down's Syndrome and its impact on listener judgement
Rodger, R. (2009) Voice quality of children and young people with Down's Syndrome and its impact on listener judgement, no. 512.
Background: Voice quality in Down's syndrome (DS) is accepted as unusual, often perceived as harsh and whispery with lower pitch and altered nasal resonance. Less is known about the resulting impact, particularly in relation to how children and young people with DS are accepted by their peers. Method: This is a quantitative study of the voice quality of children and young people with DS compared to age-matched typically-developing (TD) controls. Expert raters use the Vocal Profile Analysis Scheme to perceptually rate voice, which is compared to instrumental analysis of fundamental frequency, perturbation measures and spectral tilt. The impact of typical and atypical voice quality is evaluated in a study of listener judgments of character, ability, age, gender and social desirability using a specially designed semantic-differential questionnaire completed by special-needs and mainstream education staff and TD peers based on audio-recordings. Results: Perceptually, a number of features, including lip, tongue and jaw settings, pharyngeal constriction and respiratory support were found to be atypical compared to controls, whilst other features, notably phonation type and nasality, echoed typical patterns but were more severe in presentation in the speakers with DS. Contrary to hypotheses only spectral tilt differed significantly in instrumental analysis. All groups of raters judged the speakers with DS significantly more negatively than controls across all questionnaire parameters. TD peers showed a strong preference for the company of TD children over those with DS. Conclusions: Perceptual differences are evident in the voices of children with DS, but these are not always supported by instrumental findings, perhaps indicating that the constellation of differences give rise to more negative perception. Close agreement between education staff groups suggests that children with DS are no more disadvantaged by the perception of teachers in mainstream than in special-schools; however particular difficulties are highlighted for the development of friendships with TD peers.