When conducting assessments with individuals with autism or other developmental disorders clinicians are often interested in examining the person’s  “adaptive functioning” or how the person actually functions in every day life, usually in specific domains such as communication, sociability, motor functioning, and daily living skills. Clinicians and researchers are also interested in exploring the factors that predict adaptive functioning. One obvious candidate factor is cognitive capacity, or IQ.  It is expected that the more cognitive skills you have, the better you would do in daily living demands. However, researchers have shown that for individuals with high functioning autism, cognitive functioning is not always correlated with adaptive functioning. That is, some individuals may present cognitive skills that are within normal levels, yet display impaired adaptive functioning. Yet, less is known about the relationship between cognitive functioning and adaptive skills among children with more severe autism. For example, do children with low cognitive skills present even lower adaptive functioning or do these kids show higher adaptive functioning than expected based on their cognitive skills? Knowing this information could have implications for treatment, especially for the manner we use cognitive skills as a proxy for prognosis and to guide expectations.

This was one of a number of questions addressed by a team of researchers associated with York University in Canada. Their findings will soon be published in the Journal of Autism and Developmental Disorders. In this study, the authors examined 192 children with a DSM-IV diagnosis of autism, 66 children with a diagnosis of PDD-NOS, and 28 children with a diagnosis of mental retardation without autism. The authors were interested in examining IQ and scores and parental reports of adaptive functioning.

The authors found that while controlling for age, the association between IQ and adaptive functioning varied by level of cognitive capacity.  That is:

1. Within the group with autism and average IQ, standard scores of adaptive functioning were lower than than expected based on their IQ.

2. Within the group with mild mental retardation, their IQ and adaptive functioning skills were at the same level.

3. Within the group with moderate or severe mental retardation, adaptive functioning was actually higher than expected based on their Q.

Here is a graphical representation of these results (red columns are adaptive functioning scores, blue columns reflect IQ scores, the reddish shaded area indicates impaired region):

IQ and Cognitive Functioning in Autism

So how do they determine the “expectation”? For example, how would you know that adaptive functioning is “lower” than “expected” based on IQ?

This is usually conducted using standardized or age equivalent scores. For example, IQ is calculated based on “normative data”. In this process, the performance on IQ measures are compared to other children of the same age and same gender. So the child receives a standardized score based on how he/she performed compared to his/her peers. In the case of IQ, a score of 100 means that 50% of other children of the same age would perform better and 50% would perform worse. This same process is done to estimate adaptive functioning scores. That is, a child may receive an adaptive functioning score of 100, also meaning that 50% of his/her peers have better adaptive functioning while 50 percent have worse. So it is possible to have adaptive functioning that is below expectation based on the child’s cognitive capacity. For example, a child may have an IQ of 100 (within the average range when compared to his/her peers) but an adaptive functioning score of 70 (significantly below average when compared to his/her peers).

In conclusion, the results  for the high cognitive functioning group suggest that studies  should not use IQ solely as an outcome measure since IQ is not necessarily an indication of how a child with autism may function in everyday life. That is, some of these kids may have IQ within the normal range, yet struggle in other aspects of functioning. The authors stated:

This has clear implications for treatment outcome studies, in which average IQ may be overvalued as a good outcome without sufficient attention to functional skills. There are also clear intervention implications, such that everyday functional skills must be actively targeted in intervention research.

But what about the low cognitively functioning group? What does it mean that these kids’ adaptive functioning is in line with or above their cognitive capacity? One possibility is that targeted interventions for these kids is usually more intense than for those with higher cognitive functioning (HFA) so that by the time of this assessment, their adaptive skills have significantly improved and now match their IQ. However, it is also possible that these findings reflect a “base” of adaptive skills. That is, there is a limit on how limited your adaptive skills may be. It is possible that both the high and low functioning groups reached near that limit, so the variation in cognitive functioning was simply unrelated to adaptive skills. This is somewhat suggested by the data, in that all children, including those with HFA, scored in the impaired category in adaptive functioning. Thus, in this sample,  adaptive functioning was impaired among all participants with autism regardless of their IQ.
The reference: Perry, A., Flanagan, H., Dunn Geier, J., & Freeman, N. (2009). Brief Report: The Vineland Adaptive Behavior Scales in Young Children with Autism Spectrum Disorders at Different Cognitive Levels Journal of Autism and Developmental Disorders DOI: 10.1007/

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3 Responses to HFA vs. Severe Autism: Is adaptive functioning related to cognitive skills?

  1. JulieL says:

    Just curious:

    Could it be that due to higher interventions for the those whose adaptive score were the same or higher than IQ be in part due to a decreased frustration level vs the high functioning autistic child. That is, it is possible that the high functioning autistic child has more tantrums/higher frustration levels due to little interventions? So the other groups, while lower in IQ, have lower frustration levels, thus increasing their adaptive skills.

    Totally curious if this was mentioned at all.

    Thanks :)

    • Hmm, Julie. The authors talked about the possibility that lower functioning kids receive more intensive interventions thus their adaptive skills match their capacity. They did not discuss frustration levels as you describe. But note that the adaptive skills were still a bit higher in the HFA than in the LFA, except that for the HFA group such impaired skills were significantly below their cognitive capacity. I think this speaks to the body of research on the discrepancy between daily functioning and cognitive abilities, including the research on different types of intelligence, etc. That is, at least for the HFA group, it is clear that there is a disconnect between the two, most likely because they represent two completely different processes at the neurocognitive level – one that was spared, and one that was not. Thanks for reading!

  2. JulieL says:

    Ok, I see what you mean. But, while thinking more on this, I wonder:

    I’m still coming back to the intensity of the interventions aiding the MR groups, showing the stats they do. If there is a baseline of adaptive skills, it still could point to the fact that maybe for the MR group they are able to achieve better adaptive skills than their IQ, in result of the interventions. Meaning while the HFA and LFA may have a baseline that they should reach, and it is below their IQ, so too the MR group has a baseline, but it is possible to achieve higher baseline with interventions. Obviously the MR groups have much much lower adaptive skills, but it still makes me ponder that with these interventions, with more hands on aid with daily functioning skills, it helps the MR groups reach above IQ levels. Honestly I think all kids would achieve higher adaptive skills if someone was there to coach them through how to deal with social and independence responsibilities, at that kind of intensity level. Just look at what we know about kids with involved parents and parents choose not to be.

    Coming back to your post, you say:

    “But note that the adaptive skills were still a bit higher in the HFA than in the LFA, except that for the HFA group such impaired skills were significantly below their cognitive capacity. ”

    Actually, unless I’m looking at it wrong, group 1 that says Average, has a tad lower adaptive skills, vs group 2 that says borderline. Group 1 is HFA and Group 2 is LFA, correct?

    I’m still wondering if the higher IQ vs the “one that was not spared”, still points to a need of high interventions to allow them to achieve a higher adaptive ability. The higher the IQ, seems to point to a higher awareness that they are out of sync with normal society, possibly increasing high frustrations, inhibiting adaptive skills. To me the lower the IQ showing the higher adaptive skills in scale, showing a lesser discrepancy between the two scores, points to this.

    Also, what are the IQ and adaptive skills for non learning disorder children? I see the red area is the impairment, and I’m assuming it’s above that, but is there an average of where the two meet? Are they more even in scale?

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