""However, research in ASD has tended to use overwhelmingly White, middle to upper middle class samples, and has often excluded children with multiple disabilities and/or severe to profound intellectual disabilities". [underlining added - HLD]
The express exclusion of the severe to profound intellectually disabled in the DSM5 Autism Spectrum Disorder is found in the introductory paragraph of Mandatory Criterion A: "Autism Spectrum Disorder Must meet criteria A, B, C, and D:
A. Persistent deficits in social communication and social interaction across contexts, not accounted for by general developmental delays, and manifest by all 3 of the following:"
Even if a person exhibits all the persistent deficits of Mandatory Criterion A, B, C and D that person will not receive an autism diagnosis if the Criterion A deficits can be explained by "general developmental delays" or intellectual disability. Unlike those who will not receive an autism disorder diagnosis because they do not exhibit all the mandatory criteria for a DSM5 ASD diagnosis those with severe intellectual deficits who meet all of the criteria will still be excluded on the basis of the faulty, non evidence based logic that, even though an intellectually disabled may exhibit all the mandatory criteria for the new ASD, including the 3 deficits listed under category A, it doesn't matter because .... they are severely intellectually disabled.
No explanation for the exclusion has been provided that makes any sense. I have read the public comments by Dr. Catherine Lord, I have attended IMFAR and asked Dr. Susan Swedo directly about this exclusion and no sensible explanation for casting out the intellectually disabled from the autism spectrum has been provided.
The DSM5 generally, and the DSM5 Autism Spectrum Disorder specifically, have been explained on the basis that the changes introduced reflect current research. With respect to autism however that explanation is not satisfactory. It is not satisfactory because those with severe autism deficits, particularly those with profound intellectual disability have been excluded, merely for reasons of convenience, from much autism research, as set out in the 2008 Autism's Ouctasts comment that follows:
"Autism Research - Exclusion of Lower Functioning Autistic Subjects
In The face of Autism research as reflected in the IMFAR looking glass, Research in Autism Spectrum Disorders 2 (2008) 385–394 , authors James M. Bebko, Jessica H. Schroeder, Jonathan A. Weiss, Kerry Wells, Kristen McFee and Gayle M. Goldstein reviewed the abstracts from a major autism conference (IMFAR) from 2004 to 2006. They found an increase in the proportion of studies with preschool or infant participants. There was also a decrease in studies using lower functioning samples, and an increase in studies using Mixed samples. The use of control groups generally decreased, and the use of cognitively impaired comparison groups remained low:
In terms of the functioning level of participants, research in autism has tended to focus in recent years on the higher functioning range of autism (HFA) or those with Asperger Syndrome (AS). According to a meta-analysis of cognitive and behavioral studies by Mottron (2004), over 75% of published studies on autism in 1999–2002 were comprised of participants with no identified cognitive delay. Such focus limits the generalizability of findings, as a large portion of individuals with autism and autism spectrum disorders have associated cognitive impairments,with estimates ranging from 40% to 70% of the population (Fombonne, 2005; LaMalfa, Lassi, Bertelli, Salvini & Placidi, 2004). Clearly a more balanced range of studies, with appropriate comparison groups is necessary.
Associated with this profile in the use of comparison groups in studies presented during this time period is an apparent decreasing representation of individuals with low or moderate intellectual impairments in the studies. One risk of such a trend is that our understanding of autism may become biased to the higher end of the functioning continuum. It is important that research continue to include individuals with cognitive impairments to ensure that our knowledge based on etiology, assessment, and intervention continues to expand across the entire range of expression of the disorder." [Bold highlighting added HLD]
The autism research bias in favor of the higher end of the functioning continuum and against the intellectually disabled at the lower end of the autism spectrum has been reflected in the recent research such as fMRI research which excludes severely autistic children from their studies because of the difficulties they present as subjects particularly the difficulty in ensuring compliance and limited motion during the use of the fMRI. The researchers' solution? Just exclude and ignore the intellectually disabled, severely autistic from their studies and generalize to the entire spectrum while doing so. The researchers are willing to make an unsubstantiated generalization to the entire spectrum because it is convenient to do so. As a parent of a son with severe autism and profound developmental delays I do not have such a luxury when it comes time for anxiety inducing activities like haircuts, shaves and dental procedures.
The DSM5 authors claim that the New Autism Spectrum Disorder is based on current research. It is no surprise then that the autism research bias against those with severe to profound intellectual disability is also reflected in the express exclusion of those who display all of the mandatory criteria of the New Autism Spectrum Disorder but also have the misfortune to be intellectually disabled. Like the mainstream media, like the autism research community generally, the DSM Neurodevelopmental Committee authors of the New ASD have, for no good reason, chosen to banish the severely intellectually disabled, Autism's Outcasts.
Shame on Dr. Catherine Lord and the DSM5 Neurodevelopmental Committee. I will think of their convenience based exclusion of the intellectually disabled from autism research and the DSM5 autism disorder as I help my son shave today.