Protocol for a UK-based feasibility randomised controlled trial evaluating the BabblePlay app intervention to encourage vocalising in infants with Down syndrome

Background: Down syndrome affects around 1 in 893 live births in the UK and is the leading cause of intellectual disabilities. Children with Down syndrome experience delays in speech, language and communication, which increase with age. This delay is associated with negative social, emotional and economic outcomes in adulthood. Previous research has found that early, frequently delivered language intervention in infants with Down syndrome may be effective at improving early language skills. However, there are limited high quality, evidence-based interventions for early speech development. This study is a feasibility randomised controlled trial (RCT) for evaluating the feasibility of an app, BabblePlay, as an intervention tool for increasing vocalisations in infants with Down syndrome. Method: The study is a UK-based, remotely-delivered feasibility RCT. Online recruitment will take place July 2024 to January 2025. Children will be randomly allocated to the BabblePlay intervention group or a control group. The intervention group will be asked to use BabblePlay with their child for 5 minutes twice a day for 6 weeks (split into two 3-week periods). The control group will be asked to use a mirror with their child for 5 minutes twice a day for 3 weeks, followed by 5 minutes twice a day with the app for 3 weeks. We aim to recruit 40 children with Down syndrome aged 7–15 months. Data will be collected by BabblePlay, questionnaires and 2-day-long audio recordings at baseline and after the first and second 3-week activity periods. We will run focus groups with caregivers to explore the acceptability of the app. Feasibility (including recruitment and retention) will be assessed through progression criteria using a traffic light system. Discussion: This feasibility RCT will allow us to evaluate progression to a definitive RCT to examine whether use of the app results in changes to infant babbling and word production. This study will highlight any necessary adjustments to the protocol. It will also add to the limited research on early speech and language intervention for children with Down syndrome. Trial registration: This trial is registered with the OSF registry (registration DOI: https://doi.org/10.17605/OSF.IO/V2DNH) registered on 10 August 2024.