22 July 2011
Randomized, Controlled Trial of an intervention for Toddlers With Autism: The Early Start Denver Model (Dawson, G., Rogers, S., Munson, J., Smith, M., Winter, J., Greenson, J., Donaldson, A. and Varlet, J., 2010)
In 1987, O. Ivar Lovaas studied the efficacy of an early behavioral intervention and demonstrated that early behavioral intervention could result in many significant improvements for a child with an autism spectrum disorder (ASD) (e.g., improvements in IQ scores). His research created interest amongst parents and professionals and emphasized the importance of early behavioral intervention. The purpose of the current study was to evaluate the effectiveness (efficacy) of the Early Start Denver Model (ESDM), a comprehensive developmental behavioral intervention that was designed to improve outcomes for toddlers with an ASD.
The ESDM is a comprehensive behavioral intervention for infants to preschool-aged children. This model utilizes Applied Behavior Analysis (ABA) with developmental and relationship-based approaches. It is intended to treat toddlers as young as 12 months and is performed in a child’s natural environment.
This study included 48 children between the ages of 18 and 30 months, who were diagnosed with an ASD or pervasive developmental disorder (PDD) not otherwise specified (NOS). The children were included in the study if the met criteria for an ASD according to the Diagnostic and Statistics Manual of Mental Disorders, Fourth Edition, the Toddler Autism Diagnostic Interview (TADI), and the Autism Diagnostic Observation Schedule (ADOS). The children were randomly assigned to one of two groups: the ESDM group or an “assess and monitor” (A/M) group. In the ESDM group, children engaged in 20 hours per week of ESDM interventions from University of Washington clinicians, received yearly assessments, parent training, at least 5 hours or more per week of parent-delivered ESDM, in addition to any community services parents chose. The A/M group received yearly assessments, recommendations for intervention, and referrals to available community providers. At the end of the study, there were 24 children in the ESDM group and 21 children in the A/M group.
The ESDM group received intervention by trained therapists for 2 hour sessions, twice per day, 5 days per week for 2 years. ESDM strategies focus on interpersonal exchanges, affect regulation, shared engagement in natural “real life” settings. ESDM encourages adult responsivity and sensitivity to child cues with a focus on verbal and non-verbal communication. These strategies were based on a curriculum that addresses all developmental domains. The method of teaching was consistent with principles of ABA (e.g., operant conditioning, chaining and shaping.) and each child’s plan was individualized. Parent/family participation was highly emphasized. Parents received training on basic ESDM strategies via semimonthly meetings. Parents and family members were asked to use these strategies during everyday activities.
Parents of children in the A/M group were given referrals to community services at the beginning of the study and at two follow-up assessments. The A/M group reported an average of 9.1 hours per week of individual therapy and an average of 9.3 hours per week of group interventions (e.g., developmental preschool) across the 2 year period. There were an adequate amount of private ABA and community based services providers available.
The authors measured the effectiveness of ESDM by using assessing children at pre-treatment, and one and two years after treatment began. The following tests were used to assess progress: Autism Diagnostic Interview-Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS), Mullen Scales of Early Learning (MSEL), Vineland Adaptive Behavior Scale (VABS), and Repetitive Behaviors Scale (RBS).
Significant differences in cognitive ability were found. The ESDM group gained an average of 15.4 points on an IQ test and the A/M group gained an average of 4.4 points. The groups did not differ in their adaptive abilities, ADOS severity scores or RBS scores after one year of intervention.
The ESDM group demonstrated a significant difference in cognitive abilities. Their scores increased by an average of 17.6 points from baseline, whereas the A/M group’s scores increased by an average of 7 points. The majority of the change in cognitive scores was due to increases in expressive and receptive language. Both groups differed significantly in terms of adaptive behaviors. Results indicated that the ESDM childrens’ adaptive skills developed at a steady rate when compared to typically developing children. The A/M group showed a decline in adaptive skills by an average of 11.2 points. The groups did not differ in terms of their ADOS severity scores or RBS scores after two years of intervention.
Overall, this study suggests that the ESDM model — an intervention that uses ABA teaching strategies with a developmental and relationship based approach — can be effective for improving the outcomes of young children with ASDs. The authors stressed that parents’ use of these strategies during their daily routines was a crucial ingredient to the strategy’s success.