The five year study was based at the University of Washington (UW) Seattle and was led by Dr Geraldine Dawson, who used to be professor of psychology and director of UW's Autism Center, and is now chief science officer of Autism Speaks, an awareness, fundraising, science, and advocacy organization. A paper on the study was published online in the journal Pediatrics on 30 November.
Autism is a neurodevelopmental disorder that stays with a person for life. A person with autism has repetitive behaviors and experiences difficulty communicating verbally and interacting socially. Estimates suggest about 1 per cent of children in the US have autism.
Dawson told the press that this was the first controlled study of an intensive early intervention appropriate for children with autism who are under two and a half years old.
"Given that the American Academy of Pediatrics recommends that all 18- and 24-month-old children be screened for autism, it is crucial that we can offer parents effective therapies for children in this age range," explained Dawson.
"By starting as soon as the toddler is diagnosed, we hope to maximize the positive impact of the intervention," she added.
Previous studies have shown that interventions with preschool children with autism are effective, but testing interventions in toddlers has only started recently.
The intervention followed the Early Start Denver Model which brings together the teaching of behavioral analysis with approaches based on developmental relationships, such as parent-child and teacher-pupil.
The model is new because it blends the discipline of behavior analysis with play-based routines as a way to build a relationship with the child with autism. The approach can start with children as young as 12 months old, although in this study the youngest children were 18 months old.
Co-author Dr Sally Rogers, a professor of psychiatry and behavioral sciences at the University of California, Davis, MIND Institute in Sacramento, said:
"Infant brains are quite malleable so with this therapy we're trying to capitalize on the potential of learning that an infant brain has in order to limit autism's deleterious effects, to help children lead better lives."
For the study, which was funded by a grant from the National Institute of Mental Health, Dawson, Rogers and colleagues recruited 48 children with autism aged between 18 and 30 months old. None of the children had other health problems.
The researchers put the children into two groups. One group received 20 hours a week of intervention following the Early Start Denver Model (ESDM) for two years (comprising 2 x 2 hour sessions on five days a week, delivered by specialists from the university, plus 5 hours a week of parent-delivered therapy).
The other group of children underwent therapy in community-based programs.
At the start of the study period there was no substantial difference in functioning between the groups.
The results showed that:
- Compared to the children who had the community-based intervention, the children in the ESDM group showed significant improvements in IQ, adaptive behavior and autism diagnosis.
- Two years after starting the intervention, the ESDM children on average improved 17.6 standard score points (one standard deviation: 15 points) compared with 7.0 points in the community-intervention group, relative to their baseline scores.
- The children who had ESDM had an average improvement in in IQ of approximately 18 points compared to little more than 4 points in the community-intervention group.
- The ESDM group also showed a nearly 18 point improvement in receptive language (listening and understanding) compared to about 10 points in the community-based group.
- The adaptive behavior in the ESDM group continued to grow compared with a normative sample of typically developing children.
- In contrast, over the same 2 year period, the community-intervention group showed greater delays in adaptive behavior.
- Seven of the children in the ESDM group had enough improvement in overall skill to warrant a change in diagnosis from "autism" to the milder condition known as "pervasive developmental disorder, not otherwise specified".
- This compared to only one child in the community-base group having an improved diagnosis.
Rogers explained that they believed the ESDM group "made much more progress because it involved carefully structured teaching and a relationship-based approach to learning with many, many learning opportunities embedded in the play."
"Parental involvement and use of these strategies at home during routine and daily activities are likely important ingredients of the success of the outcomes and their child's progress," said Dawson.
The ESDM intervention took place in the toddlers' natural environment (the home) and was delivered by therapists and parents trained according to the model.
Co-author Dr Milani Smith, a licensed clinical psychologist, who oversees the UW Autism Center clinical services and provided day to day supervision on the study, said:
"Parents and therapists both carried out the intervention toward individualized goals for each child, and worked collaboratively to improve how the children were responding socially, playing with toys, and communicating."
"Parents are taught strategies for capturing their children's attention and promoting communication. By using these strategies throughout the day, the children were offered many opportunities to learn to interact with others," she explained.
"Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The Early Start Denver Model."
Geraldine Dawson, Sally Rogers, Jeffrey Munson, Milani Smith, Jamie Winter, Jessica Greenson, Amy Donaldson, and Jennifer Varley.
Pediatrics, Nov 2009.
Additional source: University of Washington.
Written by: Catharine Paddock, PhD