Reduced White Matter Integrity and Deficits in Neuropsychological Functioning in Adults With Autism Spectrum Disorder.
In adults with ASD, white-matter damage and cognitive scores both look worse, but they do not track together, so test the skill, not the scan.
01Research in Context
What this study did
Heald et al. (2020) scanned the brains of adults with autism. They used a special MRI test that maps the brain’s white-matter highways.
The team also gave each adult a short battery of thinking tests. They wanted to see if weaker highways meant lower scores.
What they found
Two cables — the anterior thalamic radiation and the cingulum — looked frayed in the ASD group. The adults also scored lower on memory, planning, and speed tests.
Yet the fraying did not line up with any one test score. A person could have the most fraying and still score in the average range.
How this fits with other research
Lo et al. (2019) saw the same MRI method in boys, but they tracked social problems, not thinking scores. Their target cable was different — the frontal aslant tract — showing the picture is bigger than one wire.
Chee et al. (2017) used EEG on children and found messy fronto-parietal waves that did match poor executive scores. So structural cables may not predict cognition, yet functional waves can — an apparent contradiction that points to timing: static structure versus live activity.
Wilson et al. (2023) later tested adults who had both ASD and intellectual disability. They added Trail Making and WAIS sub-tests and linked worse scores to longer hospital stays, extending the current work by showing cognitive profiles matter for real-life placement.
Why it matters
For you, this means a clean brain scan does not guarantee clear thinking, and vice versa. Keep using direct tests like the Trail Making Test or WAIS coding when you need to know how someone will perform at work or in a training program. Do not rely on MRI reports alone to set goals or predict support needs.
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02At a glance
03Original abstract
Autism spectrum disorder (ASD) is currently viewed as a disorder of cortical systems connectivity, with a heavy emphasis being on the structural integrity of white matter tracts. However, the majority of the literature to date has focused on children with ASD. Understanding the integrity of white matter tracts in adults may help reveal the nature of ASD pathology in adulthood and the potential contributors to cognitive impairment. This study examined white matter water diffusion using diffusion tensor imaging in relation to neuropsychological measures of cognition in a sample of 45 adults with ASD compared to 20 age, gender, and full-scale-IQ-matched healthy volunteers. Tract-based spatial statistics were used to assess differences in diffusion along white matter tracts between groups using permutation testing. The following neuropsychological measures of cognition were assessed: processing speed, attention vigilance, working memory, verbal learning, visual learning, reasoning and problem solving, and social cognition. Results indicated that fractional anisotropy (FA) was significantly reduced in adults with ASD in the anterior thalamic radiation (P = 0.022) and the right cingulum (P = 0.008). All neuropsychological measures were worse in the ASD group, but none of the measures significantly correlated with reduced FA in either tract in the adults with ASD or in the healthy volunteers. Together, this indicates that the tracts that are the most impacted in autism may not be (at least directly) responsible for the behavioral deficits in ASD. Autism Res 2020, 13: 702-714. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: White matter tracts are the data cables in the brain that efficiently transfer information, and damage to these tracts could be the cause for the abnormal behaviors that are associated with autism. We found that two long-range tracts (the anterior thalamic radiation and the cingulum) were both impaired in autism but were not directly related to the impairments in behavior. This suggests that the abnormal tracts and behavior are the effects of another underlying mechanism.
Autism research : official journal of the International Society for Autism Research, 2020 · doi:10.3389/fneur.2018.00092