Reduced White Matter Integrity and Deficits in Neuropsychological Functioning in Adults With Autism Spectrum Disorder.
Sarah M Haigh, Timothy A Keller, Nancy J Minshew and 1 others
PMID 32073209WHAT IT FOUND
Adults with autism had lower white matter integrity in long-range tracts and poorer cognitive scores than matched controls.
The integrity measures did not track with cognition or symptoms, so they did not explain the deficits.
Key findings
01Adults with autism had lower fractional anisotropy in the anterior thalamic radiation bilaterally and in the right cingulum.
02The autism group scored worse than controls on speed of processing, attention vigilance, working memory, verbal learning, visual learning, and social cognition, but not reasoning and problem solving.
03Even after accounting for IQ, fractional anisotropy in the affected tracts did not correlate with autism symptom scores or cognitive scores.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The neurotypical group was small (20 people) compared with the autism group (45 people). The tract-based spatial statistics method assumes that both groups have a similar white matter skeleton, so it may miss differences outside that skeleton. The study did not correct for multiple comparisons outside the main tract-based analysis, so exploratory correlations need caution. The groups differed in education, and education was measured only as some college or no college, which may not capture its effect. Many adults with autism had comorbid conditions or medications, and the paper did not test whether these factors affected the diffusion or cognitive results. The diffusion data used a large b value, which the authors note can affect data quality.
Declared interests
The authors declared no conflict of interest.
The easy way to misread this
Do not conclude that weaker white matter integrity explains cognitive deficits in adults with autism. The study found lower diffusion measures and poorer cognitive scores, but the diffusion measures did not track with cognitive scores or symptom scores, even after accounting for IQ.