Does early intervention work? Longitudinal results of an early intervention study of toddlers with cleft palate

Background and aim: Earlier studies of early intervention in toddlers with cleft palate are few and, in general, suffer from methodological weaknesses in terms of inadequate control for general development and matching of participants (Broen, Doyle, & Bacon, 1993; Scherer, 1999; Scherer, D'Antonio, & McGahey, 2008; Ha, 2015; Kaiser, Scherer, Frey, & Roberts, 2017). Further, none of these studies reported long-term effects. Thus, there is still no compelling evidence of the effect of early speech-language intervention in toddlers with CP. This study investigated if parent-implemented focused stimulation targeting vocabulary and consonant inventory directly affected productive vocabulary and consonant inventory in toddlers with cleft palate ± cleft lip (CP) and delayed speech and/or language acquisition compared to a matched control group of toddlers with CP who did not receive speech-language intervention. Method: A quasi-experimental pre-test post-test control group design was used to compare outcomes from the intervention (INT) group and the control (CONT) group. Participants were twenty-eight toddlers with CP aged 16-24 months. Fourteen toddlers received intervention for three months (INT group), and fourteen toddlers with CP constituted the CONT group. The groups were matched in pairs on language development. Participants were recruited from a complete birth cohort of all 103 Danish children with CP born between December 2012 and August 2014. Video recorded assessments of interaction with a caregiver were obtained pre-intervention, immediately after intervention, and six months post-intervention. Reported vocabulary from parent questionnaires were obtained at all three time points. Recordings were randomized for pre and post-status and the main transcriber was unrelated to the project. The intervention program consisted of 9 hour-long sessions in the families' homes. Parents were taught the language support strategies responsive interaction, expansions including speech recasting, and frequent modelling of target words. Treatment fidelity was monitored throughout the intervention. Results: Immediately after intervention, the INT group had significantly higher gain scores with large effect sizes for two outcome measures compared to the CONT group: observed productive vocabulary, and true consonant types in words. All long-term data have been collected, and analyses are in progress. Conclusion: Parent-implemented focused stimulation had positive short-term effects on productive vocabulary and consonant inventory in toddlers with CP and delayed speech and/or language development when compared to a matched control group. Long-term results will be reported. Most productive vocabulary and consonant inventory measures increased whether or not participants received intervention which underscores the importance of including matched control groups in intervention studies of toddlers with CP.