Randomized, Controlled Trial of an Intervention for Toddlers With Autism

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 2010;125;e17-e23; originally published online Nov 30, 2009; DOI: 10.1542/peds.2009-0958)

In 1987 Lovaas’s study on an early behavioral intervention for children with autism found that 49% of the participants were able to attend a regular class room setting in a mainstream school and had made significant IQ gains. This finding led to an increased interest into the effects of early intervention and raised questions about early plasticity in children with autism. Despite subsequent early intervention studies which have found gains in IQ for a subgroup of children, questions regarding the efficacy of early intervention persist, due to lack of methodological rigor. Authors of meta-analysis of efficacy of early behavioral intervention argue that stronger evidence that early behavioral interventions yield better outcomes than standard care is required.

Aims of the study:
This study, The Early Start Denver Model, was a randomized controlled trial of early intensive behavioral intervention. The authors hypothesized that the early intervention would result in significant improvements in cognitive abilities of young children with autism. There were three major differences in this study in comparison to previous early behavioral intervention studies. The first was that a high level of methodological rigor, including gold- standard diagnostic criteria, randomization, comprehensive outcome measures conducted by naive examiners and measures of fidelity of implementation of a manualized intervention was maintained. The second was that all children who took part in the study were less than 30 months old at entry. Thirdly was a comprehensive early behavioral intervention for infants to preschool-aged children with ASD that integrates applied behavior analysis (ABA) with developmental and relationship-based approaches. The intervention was provided in a toddler’s natural environment (the home) and was delivered by trained therapists and parents. In our study, children received structured intervention at high intensity.

Patients and Methods

Study Procedures
Forty-eight children between 18 and 30 months of age, diagnosed with autistic disorder or pervasive developmental disorder (PDD), not otherwise specified (NOS), were randomly assigned to 1 of 2 groups: (1) the ESDM group received yearly assessments, 20 hours week of the ESDM intervention parent training, and parent delivery for 5 or more hours/week of ESDM, in addition to whatever community services as chosen by the parents (2) the assess-and-monitor (A/M) group received yearly assessments with intervention recommendations and referrals for intervention from commonly available community providers in the greater Seattle region.

Participants were recruited through pediatrics centers, hospitals pre-schools and local autism organizations. Inclusion criteria included age below 30 months at entry, met the criteria for autism diagnosis and willingness to participate in a two year intervention.

Autism diagnostic measures included; the autism diagnostic interview-revised, autism diagnostic observation schedule, mullen sacles of early learning, vineland adaptive behavior scales and repetitive behavior scale.

Participants were placed into 2 groups on the basis of IQ and gender to ensure comparable IQ and gender ratios between groups. The intervention groups did not differ at baseline in severity of autism symptoms based on ADOS scores, chronological age, IQ, gender, or adaptive behaviors.

Intervention Groups:

ESDM Group:
The ESDM group was provided with intervention by trained therapists for 2-hour sessions, twice per day, 5 days/ week, for 2 years. A detailed intervention manual and curriculum were used. One or both parents were trained from the primary therapist twice monthly on the principles and specific techniques of the ESDM were taught. Parents were asked to ESDM teaching strategies during daily activities and to keep track of the number of hours during which they used these strategies. Teaching strategies are consistent principles of ABA, such as the use of operant conditioning, shaping, and chaining. Each child’s plan is individualized. There is a strong parent-family role responsive to each family’s unique characteristics. The programs were supervised graduate-level therapists who had a minimum of 5 years experience providing early intervention for young children with autism. On-going consultation was provided by clinical psychologist, speech-language pathologist, and developmental behavioral pediatrician. An occupational therapist provided consultation as needed. The intervention was delivered was delivered by therapists who typically held a bachelors degree, received 2 months of training from the lead therapist and met weekly with the lead therapist.

A/M Group:
Children who were randomly assigned to the A/M group received comprehensive diagnostic evaluations, intervention recommendations, and community referrals at baseline and again at each of the 2 follow-up assessments. Families were provided with resource and reading materials at baseline and twice a year throughout the study. The children received an average of 9.1 hours of 1:1 therapy and average 9.3 hours per week of group intervention across the 2-year period during which the intervention study was conducted.

Data Analysis:

The effect of ESDM intervention was assessed by using repeated-measures analysis of variance, baseline scores with 1- and 2-year outcome scores. The primary outcome measures were the MSEL and the VABS composite standard scores.

Secondary outcome measures were the ADOS severity score, the RBS, MSEL, and VABS subscale scores, and changes in diagnostic status (autistic disorder, PDD NOS, and no diagnosis).

No serious adverse effects related to the intervention were reported during the 2-year period.

Year 1 Outcome:
The ESDM group demonstrated an average IQ increase of 15.4 points compared with an increase of 4.4 points in the A/M group. The ESDM group improved 17.8 points on receptive language compared with a 9.8-point improvement in the A/M group. The groups did not differ in terms of adaptive behavior. The groups did not differ in terms of their ADOS severity scores or RBS total score after 1 year of intervention.

Year 2 Outcome:
Two years after the baseline assessment, the ESDM group showed significantly improved cognitive ability. The ESDM and A/M groups significantly differed in terms of their adaptive behavior. The ESDM group showed similar standard scores at the 1- and 2-year outcomes, indicating a steady rate of development, whereas the A/M group, on average, showed an 11.2-point average decline. Thus, the A/M group’s delays in overall adaptive behavior became greater when compared with the normative sample. The A/M group showed average declines in standard scores that were twice as great as those in the ESDM group in the domains of socialization, daily living skills, and motor skills. The groups did not differ in terms of their ADOS severity scores or RBS total score after 2 years of intervention.

At intake the diagnosis in each group were not significantly different. After two years the diagnosis improved for 29.2% of the children in the ESDM group but only improved for one (4.8%) child in the A/M group. However, the diagnosis changed from PDD NOS at baseline to autistic disorder at year 2 for 2 (8.3%) children in the ESDM group and 5 (23.8%) children in the A/M group. Thus, children who received ESDM were significantly more likely to have improved diagnostic status at the 2-year outcome compared with children in the A/M group.

The outcomes of this study, which involve an increase in IQ scores of 17 points and significant gains in language and adaptive behavior, compare favorably with other controlled studies of intensive early intervention which delivered discrete trial intervention.

Link to original study, click here

For the summary great thanks to: Miss Georgiana Elizabeth Barzey

For the permission to post this study, great thanks to: American Academy of Pediatrics: Brad Rysz


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