The intellectual profile of children with autism spectrum disorders may be underestimated: A comparison between two different batteries in an Italian sample.
WISC-IV can under-count IQ in low-functioning autistic kids—double-check with Leiter-3 or another non-verbal battery.
01Research in Context
What this study did
Wormald et al. (2019) gave two IQ tests to Italian children with autism.
Kids took the WISC-IV first. Then they took the Leiter-3, a test with no words and no time pressure.
The team compared scores to see if the WISC-IV missed real ability.
What they found
WISC-IV IQs were much lower than Leiter-3 IQs, especially for kids who need lots of support.
The gap shows the WISC-IV can hide what children actually know.
How this fits with other research
Nader et al. (2016) saw the same thing. They used Raven’s Matrices instead of Leiter-3 and still found WISC-IV scores were too low.
McGonigle-Chalmers et al. (2013) point to one reason: timed subtests. Their study showed that when the clock is removed, scores go up.
Mayes et al. (2008) looked only at high-functioning students. They found peaks and valleys inside the WISC-IV, but not overall underestimation. The new paper fills the gap by showing the problem is biggest for low-functioning profiles.
Why it matters
If you test a child with autism and the WISC-IV says “low,” do not stop there. Add an untimed, non-verbal tool like Leiter-3 or Raven’s. You may find stronger visual reasoning and unlock richer goals, better placements, and more respect for what the child can learn.
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02At a glance
03Original abstract
Intelligence measures are typically used in the assessment of children with autism spectrum disorders (ASD), but there is a paucity of research on the implications of such testing. In the present study, we examined children with ASD using two of the most largely adopted instruments, i.e., the WISC-IV, arguably the most utilized scale in the world; and the Leiter-3, a nonverbal scale that also excludes, from the IQ calculation, working memory and processing speed, which are points of weakness in ASD. Results showed that IQ and indices of these two batteries are strongly correlated. However, the WISC-IV IQ might underestimates the potential of children with ASD, particularly in children with a low functioning profile. These hold true for both the full scale IQ and three out of four indices of the WISC-IV, with remarkable implications for both assessment and treatment of these children. Practitioners working with children with ASD should be aware that the battery that they are using might severely affect the estimation of these children's potential.
Research in developmental disabilities, 2019 · doi:10.1016/j.ridd.2019.04.009