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

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. TRIAL REGISTRATION Current Controlled Trials ISRCTN20953675.