From 30% to 60% of children with an autism spectrum disorder (ASD) have an IQ measure that falls in the intellectual disability (ID) range.
(Catherine Rice et al., Risk for cognitive deficit in a population-based sample of U.S. children with autism spectrum disorders: Variation by perinatal health factors, Disability and Health Journal, Volume 3, Issue 3, Pages 202-212 (July 2010)
The above range refers to the entire range of Autism Spectrum Disorders including Aspergers whch, by definition, excludes anyone with an intellectual disability. If you exclude Aspergers from the calculation then you are looking at a figure similar to the 80% figure referenced for non-Aspergers autism referenced in the 2006 Canadian Senate brief of the Canadian Psychological Association. Yet we continue to ignore intellectual disability in our public discussion of autism. Intellectual Disability is very much the elephant in the autism room.
One aspect of autism awareness events that puzzles me about autism awareness events is the extent to which they don't really raise awareness about the realities of autism disorders. In many cases there will be no mention of the fact that autism disorders are exactly that ... disorders ... diagnostic categories listed in the Diagnostic and Statistical Manual of Mental Health Disorders of the American Psychiatric Association. As the father of a son with Autistic Disorder and "profound developmental delays" .... intellectual disability .... I have long been annoyed by the persistent attempts to hide under euphemisms like "profound developmental delay" and under blurred professional terms like "co-morbidity" the obvious fact that Autistic Disorder is actually a form of intellectual disability. I am not just talking about IQ test scores although I am not a member of the trendy IQ scores don''t count crowd. Serious functional impairment in daily life is a real characteristic of Autistic Disorder.
With news that the DSM5 would formally combine Aspergers with Autistic Disorder and PDD-NOS into the New Autism Spectrum Disorder the media rushed to report that some with Aspergers were concerned about being lumped together with the "other" autism categories, the categories which included those with Intellectual Disabilities. No discussion of, absolutely no discussion, occurred, outside of this humble blog, about the possible negative impact on the many with Autistic Disorder and Intellectual Disability of having the Intellectual Disability aspect of autism hidden further from public view.
Don't hold your breath while you search for information about Intellectual Disability and Autism on World Autism Awaerness Day. On World Autism Awareness Day you are unlikely to find any mention of this important aspect of autism reality. Unless you check this blog, Facing Autism in New Brunswick.