The Effects of Palatal Expansion on Speech Articulation in Children With Unilateral Versus Bilateral Cleft Lip and Palate

OBJECTIVE: Children with cleft lip and palate (CLP) often require palatal expansion before secondary alveolar bone grafting (SABG). As individuals with CLP frequently experience speech disorders, the expander may further impact speech due to the space it occupies intraorally. This study aimed to evaluate the effects of expansion and cleft type on speech outcomes. METHODS: This was a prospective cohort study of 30 patients (37% females; mean age 8.95 ± 1.04 y) with CLP, including 16 bilateral CLP and 14 unilateral CLP. Speech recordings and self-perception questionnaires were obtained at 6 time points: before expansion (T1), after expander insertion (T2), during expansion (T3), during retention (T4), after expander removal (T5), and after SABG (T6). The main outcome measures were self-perception questionnaire ratings from patients and parents; consonant spectral center of gravity (CoG) of /ʃ/, /s/, and /z/; the first (F1) and second (F2) vowel formants of /a/, /i/, and /u/; and nasalance scores. The effects of time point and cleft type were analyzed using a linear mixed-effects model with post hoc Tukey-Kramer tests. RESULTS: Significant changes in speech ratings over time were observed ( P <0.01), but cleft type had no effect. Both time and cleft type significantly influenced consonant CoG and high vowel formants ( P <0.05). Speech nasality was unaffected by cleft type or time point. CONCLUSIONS: Expansion adversely affected self-perceived and acoustic speech measures, with cleft type further influencing acoustic outcomes. Clinicians can use the results to counsel patients on the speech effects of palatal expansion and improve treatment acceptance.