Tongue dorsum activity in children with velopharyngeal insufficiency vs. typically developing children.

To investigate whether children with velopharyngeal insufficiency (VPI) exhibit increased elevation and retraction of the tongue dorsum. Two quantitative metrics of tongue dorsum activity: Dorsum excursion Index (DEI) and Tongue Constraint Position Index (TCPI) were captured using mid-sagittal images of the tongue obtained from Ultrasound Tongue Imaging. Participants: Six children with velopharyngeal insufficiency (VPI), six children with palate (w/wo cleft lip) without velopharyngeal insufficiency (wo VPI) and ten typically developing children aged 6-15 repeated six different consonants in aCa and iCi contexts five times. A linear mixed-effect model was used to examine the response variables across three groups. Overall, DEI was not significantly higher in the VPI group than in the other two groups. Also, TCPI was not significantly lower in the cleft palate group (VPI and wo VPI). However, significant differences were detected between certain phonetic contexts in the VPI group. In addition, a significant interaction between group and consonant was found in the context of /i/. These findings suggest that the presence of VPI may not lead to a uniform increase in tongue dorsum elevation or retracted position across all speech sounds. Rather, the articulatory behaviours of children with VPI may be influenced by the specific phonetic context and individual variability.