Parent mediated social communication therapy for young children with autism (PACT) long term follow up of a randomised controlled trial
Summary Background It is not known whether early intervention can improve long term autism symptom outcomes. We aimed to follow up the Preschool Autism Communication Trial (PACT) to investigate whether the PACT intervention had a long term effect on autism symptoms and continued effects on parent and child social interaction. Methods PACT was a randomised controlled trial of a parent mediated social communication intervention for children aged 2 4 years with core autism. Follow up ascertainment was done at three specialised clinical services centres in the UK (London, Manchester, and Newcastle) at a median of 5*75 years (IQR 5*42 5*92) from the original trial endpoint. The main blinded outcomes were the comparative severity score (CSS) from the Autism Diagnostic Observation Schedule (ADOS) the Dyadic Communication Assessment Measure (DCMA) of the proportion of child initiatiations when interacting with the parent, and an expressive receptive language composite. All analyses followed the intention to treat principle. PACT is registered with the ISRCTN registry, number ISRCTN58133827. Findings 121 (80% of the 152 trial participants (59 [77% of 77 assigned to PACT intervention vs 62 [83% of 75 assigned to treatment as usual) were traced and consented to be assessed between July, 2013, and September, 2014. Mean age at follow up was 10*5 years (SD 0*8) Group difference in favour of the PACT intervention based on ADOS CSS of log odds effect size (ES) was 0*64 (95% CI 0*07 to 1*20) at treatment endpoint and ES 0*70 (95% CI 0*05 to 1*47) at follow up, giving an overall reduction in symptom severity over the course of the whole trial and follow up period (ES 0*55, 95% CI 0*14 to 0*91, p=0*004) Group difference in DCMA child initiations at follow up showed a Cohen's d ES of 0*29 (95% CI 0.02 to 0.57) and was significant over the course of the study (ES 0*33, 95% CI 0*11 to 0*57, p=0*004) There were no group differences in the language composite at follow up (ES 0*15, 95% CI 0*23 to 0*53) Interpretation The results are the first to show long term symptom reduction after a randomised controlled trial of early intervention in autism spectrum disorder. They support the clinical value of the PACT intervention and have implications for developmental theory. Funding Medical Research Council.
The Lancet