Randomized, Controlled Trial of the LEAP Model of Early Intervention for Young Children with Autism Spectrum Disorders.
Strain, P. S. & Bovey, E. H. II. (2011). Randomized, controlled trial of the LEAP model of early intervention for young children with autism spectrum disorders. Topics in Early Childhood Special Education, 20 (10), 1-22.
Reviewed by: Rebecca Schulman, Rutgers University
Why study this topic?
Previous research on early intervention for autism spectrum disorders (ASDs) has primarily focused on programs that emphasize discrete trial methods in settings specifically for children with ASDs. Intervention models that involve inclusion in public school settings, such as Learning Experiences and Alternative Program for Preschoolers and Their Parents (LEAP), have received much less attention. It is essential to assess different types of early intervention programs to ensure that educational resources are being used in the most effective way possible.
What did the researchers do?
The researchers aimed to evaluate the effectiveness of LEAP, a manualized inclusion program for preschool children with ASDs. Typically developing peers are taught to facilitate social and communication behaviors of children with ASDs during daily preschool routines. LEAP also involves daily data collection, skill training for families, and a variety of science-based intervention approaches, including errorless learning, time delay, incidental teaching, pivotal response training, and picture exchange communication system.
The current study was a randomized control trial (RCT) to better determine the overall efficacy of enrollment in LEAP. Two hundred and thirty preschool teachers and 294 children with ASDs participated. Classrooms were randomly assigned to either the full LEAP replication or a comparison condition which consisted of LEAP’s intervention manuals, videos, and training presentation materials but did not include follow-along training. Intervention lasted for two years. Children were assessed at three time points: before the start of the assigned intervention, after about one year of intervention, and at the conclusion of the second year of participation. At each time point, measures were taken to assess defining characteristics of autism, cognitive ability (IQ), receptive and expressive communication competence, social skill development, and problem behavior. In addition, this study tried to account for limitations of previous RCTs by assessing if treatment was being implemented properly and measuring teacher satisfaction of the intervention.
What did the researchers find?
The results indicate that, although the groups were equivalent on all child and teacher measures prior to intervention, the LEAP group averaged twice the gain in IQ and language development, as well as twice the reduction on a measure of autism symptoms, relative to the comparison group. The LEAP group also showed a greater increase in social behavior and decrease in problem behavior than did the comparison group. Furthermore, after one year, the full replication LEAP classes adhered to proper treatment implementation 53% of the time, which rose to 87% at the end of year two. The comparison classes showed 31% adherence to program implementation at the end of year one, which only rose to 38% after the second year. Lastly, ratings from teachers in the treatment classes showed that they liked the LEAP program and thought that it was responsible for the improvements seen in their students.
What do the results mean?
This study was the first RCT of a classroom-based intervention in a public school setting for young children with ASDs. It is also the first RCT to collect data on implementation of the treatment and one of the first to evaluate satisfaction with the intervention in addition to Smith, Groen, and Wynn (2000). Additionally, it was the first RCT to show large developmental improvements in children with ASDs using methods other than discrete trials. One limitation of the current study is that ASDs diagnosis and change in ASDs symptoms were assessed by screening questionnaires rather than by standard diagnostic measures involving direct observation. Despite this limitation, results suggest that children in the intervention group made considerable cognitive, social, language and behavioral gains in relation to the comparison group.
Smith, T., Groen, A., & Wynn, J. W. (2000). Randomized trial of intensive early intervention for children with pervasive developmental disorder. American Journal on Mental Retardation, 104, 269-285.