Outcomes of population based language promotion for slow to talk toddlers at ages 2 and 3 years: Let's Learn Language cluster randomised controlled trial

Abstract

Objective: To determine the benefits of a low intensity parent-toddler language promotion programme delivered to toddlers identified as slow to talk on screening in universal services.

Design: Cluster randomised trial nested in a population based survey.

Setting: Three local government areas in Melbourne, Australia.

Participants: Parents attending 12 month well child checks over a six month period completed a baseline questionnaire. At 18 months, children at or below the 20th centile on an expressive vocabulary checklist entered the trial.

Intervention: Maternal and child health centres (clusters) were randomly allocated to intervention (modified “You Make the Difference” programme over six weekly sessions) or control (“usual care”) arms.

Main outcome measures: The primary outcome was expressive language (Preschool Language Scale-4) at 2 and 3 years; secondary outcomes were receptive language at 2 and 3 years, vocabulary checklist raw score at 2 and 3 years, Expressive Vocabulary Test at 3 years, and Child Behavior Checklist/1.5-5 raw score at 2 and 3 years.

Results: 1217 parents completed the baseline survey; 1138 (93.5%) completed the 18 month checklist, when 301 (26.4%) children had vocabulary scores at or below the 20th centile and were randomised (158 intervention, 143 control). 115 (73%) intervention parents attended at least one session (mean 4.5 sessions), and most reported high satisfaction with the programme. Interim outcomes at age 2 years were similar in the two groups. Similarly, at age 3 years, adjusted mean differences (intervention−control) were −2.4 (95% confidence interval −6.2 to 1.4; P=0.21) for expressive language; −0.3 (−4.2 to 3.7; P=0.90) for receptive language; 4.1 (−2.3 to 10.6; P=0.21) for vocabulary checklist; −0.5 (−4.4 to 3.4; P=0.80) for Expressive Vocabulary Test; −0.1 (−1.6 to 1.4; P=0.86) for externalising behaviour problems; and −0.1 (−1.3 to 1.2; P=0. 92) for internalising behaviour problems.

Conclusion: This community based programme targeting slow to talk toddlers was feasible and acceptable, but little evidence was found that it improved language or behaviour either immediately or at age 3 years.