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Are the Majority of Children with Autism Mentally Retarded?. Meredyth Goldberg Edelson. Relation to Classic Article. Creak (1961) was part of a working party in Great Britain that was responsible for identifying diagnostic criteria for autism.
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Are the Majority of Children with Autism Mentally Retarded? Meredyth Goldberg Edelson
Relation to Classic Article • Creak (1961) was part of a working party in Great Britain that was responsible for identifying diagnostic criteria for autism. • They identified nine characteristics, including mental retardation • Creak (1961) claimed that mental retardation was regarded as a “sine-qua-non,” meaning an essential aspect of autism.
Purpose of Edelson’s Article • Edelson (2006) conducted a literature review to determine the origin of the claim “the majority of children with autism have mental retardation” and whether it had any empirical basis.
Literature Review • By conducting an online search, looking through references lists and by examining textbooks on psychology and related areas, Edelson found 215 articles that made claims about the comorbidity of autism and mental retardation.
Did the reports of prevalence rates of MR in children with autism come from empirical sources? • 58 articles made empirical claims, 165 articles made nonempirical claims, and 8 articles made both empirical and nonempirical claims. • Thus, only 26% of the claims came from empirical sources
Results from Nonempirical Articles • Of the nonempirical articles, 104 cited specific prevalence rates of MR in children with autism. The mean rate was 77.83% and the percentage that was cited most often was 75%. • The number of articles that claimed that the majority of children with autism have MR has significantly increased over the years.
Results from Empirical Articles • The mean prevalence rate in the empirical articles was 75.28%, which is similar to the mean rate obtained from the nonempirical studies. • However, in the 3 articles published prior to 1960, the mean prevalence rate was 34.33% whereas the mean prevalence rates reported after 1960 were at least 30% higher.
Could the nonempirical sources of prevalence rates be traced back to empirical studies? • Of the 165 nonempirical articles, 53% of the citations did not trace back to empirical data. • Unfortunately, most readers would not realize that the claims did not come from an empirical source.
Were the methods used in empirical studies valid considering the interference of autism with the testing procedure? • Children with autism have language and attention deficits as well as other characteristics than can interfere with the intelligence testing procedure. • When these characteristics are not taken into consideration, the IQ test may not accurately reflect the child’s intelligence level • Only 35 (out of 58) of the empirical articles provided information about the methods they used to test the intelligence of children with autism in their sample.
Which Methods were Used? • Verbal measures and timed (performance) measures were used and some studies used developmental or adaptive scales to measure intelligence. Developmental and adaptive scales are not measures of intelligence.
Conclusions • It may not be warranted to assume that the majority of children with autism have MR. • Recent findings from epidemiological surveys indicate that 40 to 55% of children with autism have MR. • When researchers use intelligence measures that take into account the interfering characteristics of autism, much lower rates of MR are found than those reported in the literature
Importance of Article • It raises awareness of one major assumption that is made about children with autism. The view that most children with autism have MR is widespread. • Families may be more optimistic about their child’s abilities and outcomes and have higher expectations (and hopefully seek treatment). • Also raises awareness that it is likely that many claims in the literature (not just in the autism literature) are not based on empirical data or that they are based on old empirical data. Therefore it is important to think critically about what you read.
References Creak, M. (1961). Schizophrenic syndrome in childhood. Lancet, 2, 818. Edelson, M. G. (2006). Are the majority of children with autism mentally retarded? A systematic evaluation of the data. Focus on Autism and Other Developmental Disabilities, 21, 66-83.