Lateralization in individuals with high-functioning autism and Asperger's disorder: a frontostriatal model.
High-functioning autism shows left-side executive hiccups that Asperger's does not, so check subtype before you build supports.
01Research in Context
What this study did
Researchers compared adults with high-functioning autism, Asperger's disorder, and typical controls on brain-sided tasks. They used puzzles that tax the left or right side of the brain. The goal was to see if one side works poorly in autism but not in Asperger's.
What they found
Only the high-functioning autism group stumbled on left-brain jobs like planning and quick rule shifts. The Asperger's group scored like typical adults on every task. The gap shows up only when the left side must lead.
How this fits with other research
Richmond (1983) first saw more left-brain trouble in autism. Mansell et al. (2002) sharpens that claim by splitting autism from Asperger's, showing the flaw lives in autism alone.
Weiss et al. (2001) ran a near-copy study one year earlier. They also found a thinking-speed lag in high-functioning autism but not in Asperger's. The pair forms a clean replication pair.
Granieri et al. (2020) pooled 16 brain-scan papers and saw weak parietal help during executive jobs across all ASD. The new data add timing detail: the left-brain stall is autism-only, not ASD-wide.
Why it matters
If you test a client with high-functioning autism, expect slow left-brain tools like planning or set-shifting. Give extra prompts, written steps, or left-space cues. Do not assume the same weakness in clients with Asperger's labels; their executive scores may look typical. Tailor your support plan to the subtype, not the umbrella term.
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02At a glance
03Original abstract
Neurobiological and behavioural studies of possible left hemisphere dysfunction in autism have generated conflicting results. Left hemisphere dysfunction may manifest in autism only in tasks that invoke executive functions. Moreover, left hemisphere dysfunction may underpin autism but not Asperger's disorder. We thus aimed to systematically investigate reports of anomalous lateralization in individuals with high-functioning autism and Asperger's disorder. Two of the tasks were sensitive to executive dysfunction: a serial choice reaction-time task and a Posner-type paradigm; the remaining tasks instead investigated aspects of perceptual lateralisation. Compared with age- and IQ-matched controls, the autism group displayed deficiencies in right hemispace (and by implication, left hemisphere) performance on both executive function tasks; however, this group demonstrated normal lateralization effects on the nonexecutive, visual-perceptual tasks. In contrast, the Asperger's disorder group showed similar laterality effects to their age- and IQ-matched controls on both executive and nonexecutive function tasks. The etiological relevance of this neurobehavioral dissociation between high-functioning autism and Asperger's disorder was discussed; in particular, it was suggested that the period where dominance shifts from right to left hemisphere is important in whatever process might dictate the emergence of either autism or Asperger's disorder.
Journal of autism and developmental disorders, 2002 · doi:10.1023/a:1016387020095