Efficacy of a motor speech intervention in children with cerebral palsy: A randomized controlled trial

AIM: To evaluate the effects of an intensive motor speech intervention based on Motor Speech Intervention-Prompts for Restructuring Oral Muscular Phonetic Targets (MSI-PROMPT) on speech and perceived intelligibility in children with cerebral palsy (CP) aged 3 to 10 years. METHOD: This was a waiting list-control randomized parallel clinical trial. Participants were randomized to a 3-week MSI-PROMPT programme or waitlisted to standard care (WL-SC). Primary outcomes were the Intelligibility in Context Scale, the Viking Speech Scale (VSS), and the Phonetic Inventory. After the intervention, group comparisons were performed using analysis of covariance, adjusting for baseline scores, age, and sex; results were reported as the adjusted mean difference (AMD) and 95% confidence interval (CI). Interactions with baseline severity were explored using simple-effect analyses. RESULTS: Sixty children (30 MSI-PROMPT, 30 WL-SC; n = 20 females; mean age 5 years 3 months, SD = 2 years 2 months; range = 3 years 0 months-9 years 11 months) completed the trial. After the intervention, the MSI-PROMPT group showed significantly greater improvements than the WL-SC group in Intelligibility in Context Scale (AMD = 0.38; 95% CI = 0.23-0.53, p < 0.001), VSS (AMD = -0.31; 95% CI = -0.50 to -0.12; p = 0.002), and Phonetic Inventory (AMD = 1.21; 95% CI = 0.60-1.81; p < 0.001). VSS gains were larger in children with higher baseline severity (VSS = 3: AMD = -0.35, p = 0.001; VSS = 4: AMD = -0.64, p = 0.002). Exploratory within-group analysis in the MSI-PROMPT group suggested that observed gains were maintained at the 3-month follow-up. INTERPRETATION: Intensive MSI-PROMPT significantly improved perceived intelligibility and speech skills in children with CP compared to standard care. Follow-up observations at 3 months suggested potential stability of gains, although these within-group findings remain exploratory because of the lack of a parallel control group. Exploratory analyses also suggested that treatment effects may vary according to baseline severity, supporting further investigation of individualized intervention planning.