Intelligence patterns among children with high-functioning autism, phenylketonuria, and childhood head injury.
Low Comprehension versus high Block Design on the Wechsler signals executive-based social reasoning problems in high-functioning autism.
01Research in Context
What this study did
The team gave Wechsler IQ tests to three groups of kids. Group one had high-functioning autism. Group two had PKU that was poorly controlled. Group three had a past head injury that hurt the front part of the brain.
They looked at two sub-test scores. Comprehension measures social reasoning. Block Design measures visual puzzle skill. They asked which group showed low Comprehension yet high Block Design.
What they found
Autistic kids scored lower on Comprehension than on Block Design. The PKU group showed the same gap. The head-injury group showed the opposite gap.
The shared profile hints that autism and PKU both tax the brain’s dopamine system. That system powers executive skills like planning and social insight.
How this fits with other research
Iversen et al. (2021) pooled data from almost the kids. They found that poor executive function goes hand in hand with more repetitive behaviors in autism. The Wechsler gap seen here is one early marker of that link.
Gandhi et al. (2022) asked teachers to rate Grade 1-the students with ASD. Even mild ASD showed big executive-function problems on the BRIEF-2. The 1999 IQ pattern now shows up in real classrooms, not just clinics.
Smith et al. (2010) used see-know tasks instead of Wechsler. They still found moderate theory-of-mind gaps in high-functioning autism. Different tests, same social-cognitive weak spot.
Why it matters
You can spot executive risk with one quick IQ sub-test pair. If Comprehension is below Block Design, plan extra executive supports. Use visual schedules, break social rules into small steps, and teach self-monitoring. Targeting these skills early may lower future repetitive behaviors and boost flexible thinking.
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02At a glance
03Original abstract
High-functioning children with autistic-spectrum disorder show the typical pattern of lower Comprehension relative to their own scores on Block Design. This profile is shared, almost exactly, by age- and IQ-matched children with poorer control PKU. Quite distinct profiles are shown by children with better control PKU, who show no difference between Block Design and Comprehension, and by children with head injury involving frontal lobe contusion, who show slightly better Comprehension that Block Design. The data bear on several questions: the relation between Comprehension deficits and language functions measured by Vocabulary; the limits of the advantages conveyed by higher IQ to autistic individuals; whether impaired Comprehension in autism indexes persisting symptoms and/or impairments on theory of mind tasks; the possibility that dopamine deficiency is common to autism and poorer control PKU; and the need for future research aimed at understanding the relations among neurodevelopmental disorders.
Journal of autism and developmental disorders, 1999 · doi:10.1023/a:1025962431132