An ultrasound investigation of tongue dorsum raising in children with cleft palate +/- cleft lip

Objective: This study aimed to determine whether overuse of the tongue dorsum, or back, is evident in children with repaired cleft palate with or without cleft lip (CP+/-CL). We hypothesized that children with CP+/-CL would show overuse of the tongue dorsum, a compensatory pattern.
Method: Secondary data analysis of mid-sagittal ultrasound tongue imaging data from 31 children with CP+/-CL and 29 typically developing children were used. We annotated the consonants /ʃ, t, s, k/ at the point of maximum constriction in an /aCa/ environment. Children with CP+/-CL said the tokens 10 times, typically developing children said them once. We automatically fitted splines to the tongue contour and extracted the Dorsum Excursion Index (DEI) for each consonant. This metric measures the relative use of the tongue dorsum, with more posterior consonants having higher values. We compared DEI values across groups and consonants using a linear mixed effects model. DEI was predicted by the interaction of consonant (baseline: /ʃ/) and speaker type (baseline: TD), including by-speaker random slopes for consonant and random intercepts for speaker.
Results: Overall DEI was not higher in children with CP+/-CL compared to typically developing children. Between groups the only significant difference was the position of /k/ relative to /ʃ/, where the difference between these two consonants was smaller in the children with CP+/-CL.
Conclusions: There was no support for the hypothesis that overuse of the tongue dorsum is a common characteristic in children with repaired CP+/-CL. However, individual children may present with this pattern.