DAS-II Cognitive Profiles Are Not Diagnostically Meaningful For Autism: A ROC Analysis.
DAS-II nonverbal>verbal splits are only 54 % accurate for autism—worse than a coin flip—so quit using them for diagnosis.
01Research in Context
What this study did
The team looked at DAS-II scores from kids with and without autism.
They used ROC curves to see if the classic "nonverbal IQ higher than verbal IQ" pattern could flag autism.
Every child already had a diagnosis, so the question was: does the profile alone get it right?
What they found
No profile beat a coin toss. The best AUC was 0.56, which is basically chance.
Even the famous nonverbal>verbal split was wrong almost half the time.
The authors say: stop using these splits to help diagnose autism.
How this fits with other research
Lunardon et al. (2023) ran the same ROC check on WISC-IV profiles for dyscalculia and also got poor accuracy. Both papers warn: cognitive indexes are not stand-alone diagnostic tools.
Papadopoulos et al. (2013) found a 21-point IQ gap between Leiter-R and SB5 in kids with ASD. That spread shows DAS-II numbers can swing widely, backing up why the profile is unreliable.
Older work like Saemundsen et al. (2003) already showed ADI-R and CARS only agree about two-thirds of the time. Green et al. (2020) extends that line: even shiny cognitive patterns fail the accuracy test.
Why it matters
If you use nonverbal>verbal splits to justify an autism label, you will misclassify almost half of the kids. Rely on gold-standard tools like ADOS-2 and good clinical judgment instead. When you write reports, drop language like "cognitive profile consistent with ASD." Just describe the scores and move on.
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02At a glance
03Original abstract
Intelligence assessment is an integral part of a comprehensive autism evaluation. Many past studies have described a cognitive profile of autistic individuals characterized by higher nonverbal than verbal IQ scores. The diagnostic utility of this profile, however, remains unknown. We leveraged receiver operating characteristic methods to determine the sensitivity, specificity, and area under the curve (AUC) of three different IQ profiles in a large sample of children who have an autism spectrum disorder diagnosis (N = 1,228, Simons Simplex Collection) who completed the Differential Ability Scales-Second Edition (DAS-II), School Age compared to the normative sample provided by the DAS-II publisher (N = 2,200). The frequently discussed nonverbal > verbal IQ profile performed near chance at distinguishing ASD from normative individuals (AUC: 0.54, 95% CI [0.52-0.56]), and performed significantly worse for females than males (AUC: females: 0.46 [0.41-0.52]; males: 0.55 [0.53-0.58]). All cognitive profiles showed AUC < 0.56. We conclude that while significant differences between verbal and nonverbal IQ scores exist at the group level, these differences are small in an absolute sense and not meaningful at an individual level. We do not recommend using cognitive profiles to aid in autism diagnostic decision-making. LAY SUMMARY: Some researchers and clinicians have reported an "autistic cognitive profile" of higher nonverbal intelligence than verbal intelligence. In an analysis of over 1,000 autistic children, we found that the group's average nonverbal intelligence is usually higher than their verbal intelligence. However, this pattern should not be used by clinicians to make an individual diagnosis of autism because our results show it is not helpful nor accurate.
Autism research : official journal of the International Society for Autism Research, 2020 · doi:10.1002/aur.2336