08 July 2011
There have been questions about ABA’s effectiveness with children with Autism and mental retardation (MR). MR is measured by IQ and is categorized into ranges of mild, moderate, severe, and profound impairment. Approximately 70% of children with Autism also have a diagnosis of MR, although this statistic has been the source of some debate. There are studies which have examined the effectiveness of ABA specifically with children with Autism and MR. A few are reviewed below.
One such study was conducted by Smith, Eikeseth, Klevstrand and Lovaas in 1997. This study examined 21 preschoolers with Autism and MR. The average IQ of the students before treatment was 35 (i.e., severe MR). Students in the treatment group received 30 hours of ABA per week, and children in the non-treatment group received “minimal” treatment. After 35 months the students in the treatment group obtained significantly higher average IQ scores and demonstrated more expressive speech than the non-treatment group. The study also reported a decrease in problem behaviors for both groups of students. In a similar study, Eldevik, Eikeseth, Jahr and Smith (2006) gave children with Autism and MR 22 hours of ABA per week for 2 years. The average IQ of students before treatment was 41. After 2 years, the treatment group showed significantly more change than the non-treatment group in intellectual ability, receptive language, and spoken language. Both of these studies reported smaller increases in IQ and language than what has been observed in higher functioning people; however, both demonstrated that people with Autism and MR make steady improvements over time in response to ABA-based therapies.
It is also important to note that because MR is considered so prevalent in people with Autism, most of the research that examines Autism treatments includes children with Autism and MR. Therefore, the majority of results, unless explicitly stated, can be generalized, to a limited degree, to people with Autism and MR.
Lovaas’ initial study of Discrete Trial Training for children with Autism included children with MR. In this study (1987) the children in the treatment group showed increases in IQ scores of an average of 30 points overall after treatment. Interestingly, there were 10 children with moderate to severe MR included in the treatment group. After treatment, only 3 of the 10 children remained in the moderate to severe range of MR. In other words, 70% of the children with Autism and MR moved out of the moderate to severe MR ranges.
Howard, Sparkman, Cohen, Green and Stanislaw (2005) included children with MR in their study and found that the children who received intense behavioral treatment (IBT) showed significant progress in cognitive, language, social, and self-help skills. Sallows and Gaupner (2005) included students who had IQ’s ranging from 35 to 75 (i.e., mild to moderate MR). After 4 years of treatment 11 of the 23 children had IQ scores in the normal range (i.e., above 85). The authors identified two classes of learners: rapid and moderate learners. The authors said this about moderate learners: “Although these children did not ‘catch up’ to peers, they did show increases in developmental age equivalents. At the end of the study these children were continuing to gain skills at the rate of 3.4 to 4.3 months per year (in language and social skills).”
The list of studies which demonstrate that ABA significantly helps children with Autism and MR is lengthy. After having reviewed just a few of them here, it is apparent that there can be no question about whether ABA is an effective treatment for children with Autism and certain levels of MR. The diagnosis of MR may affect other treatment variables, such as length of treatments, intensity, and treatment goals and appears to impact the rate of acquiring new skills.