Abstract
INTRODUCTION: The goal of the present study was to analyze the auditory-perceptual and acoustic characteristics of sibilant and vowel sounds over the course of rapid palatal expansion treatment in children with cleft lip and palate (CLP). METHODS: A Nasometer headset was used to record vowel-consonant-vowel (VCV) nonwords with the sibilants "s, z, sh" and the vowels "a, i, u" in 28 children with CLP at six time points. Auditory-perceptual and acoustic analyses of 4,500 VCV productions were obtained. RESULTS: Perceived sibilant errors increased after expander insertion (T2) and gradually returned to pretreatment levels. The s-sound was distorted most frequently (38.3%), while the fewest errors were noted for sh (28.6%). Auditory-perceptual and acoustic measures of nasality increased from the baseline before expander insertion (T1) to the final time point after secondary alveolar bone-grafting (T6). Variability between repeated productions was noted for 26.6% of consonant productions. A cluster analysis showed that 13 children with a higher error rate of 43.9% at T1 had a lower rate of 37.4% at T6 while 15 children with a lower error rate of 16.1% at T1 had a higher rate of 26.6% at T6. CONCLUSION: Speech errors increased at T2, followed by gradual improvement until T6. The cluster analysis found that some patients in this study showed an increase of pathological speech characteristics over the course of the palatal expansion treatment. More research is needed to investigate how the cleft team can identify and mitigate possible adverse effects for speech.