Increased coherence of white matter fiber tract organization in adults with Asperger syndrome: a diffusion tensor imaging study.
Adults with Asperger syndrome show globally higher white-matter organization, not damage.
01Research in Context
What this study did
The team scanned the adults with Asperger syndrome and 28 matched controls.
They used diffusion tensor imaging (DTI) to map white-matter fibers across the whole brain.
The goal was to see if the wiring looked different in adults who grew up with Asperger’s.
What they found
Every major tract showed higher fractional anisotropy (FA) in the Asperger group.
Higher FA means the fibers are more tightly bundled and lined up.
The boost was seen in left and right sides, front to back—no single spot drove the effect.
How this fits with other research
Hanaie et al. (2014) also used DTI, but in kids and only the corpus callosum. They found lower FA in the callosum linked to social problems. Ulrika’s adults had higher FA everywhere, so age and tract choice matter.
Faja et al. (2009) showed adults with ASD were worse at reading faces. Ulrika’s team shows their wires are more organized, not less. The contradiction hints that extra coherence may not help social circuits do their job.
Lugnegård et al. (2011) found a large share of adults with Asperger’s have major depression. Pair that with Ulrika’s data and you get a picture: brains are wired tightly, yet mood and social life still struggle.
Why it matters
When you see an adult client with Asperger’s, remember their brain is not missing cables—the cables are extra tidy. That may explain rigid thinking or trouble shifting sets. Use crystal-clear instructions and give extra transition warnings; their strong but fixed wiring needs time to reroute.
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02At a glance
03Original abstract
To investigate whether there are global white matter (WM) differences between autistic and healthy adults, we performed diffusion tensor imaging (DTI) in 14 male adults with Asperger syndrome (AS) and 19 gender-, age-, and intelligence quotient-matched controls. We focused on individuals with high-functioning autism spectrum disorder (ASD), AS, to decrease heterogeneity caused by large variation in the cognitive profile. Previous DTI studies of ASD have mainly focused on finding local changes in fractional anisotropy (FA) and mean diffusivity (MD), two indexes used to characterize microstructural properties of WM. Although the local or voxel-based approaches may be able to provide detailed information in terms of location of the observed differences, such results are known to be highly sensitive to partial volume effects, registration errors, or placement of the regions of interest. Therefore, we performed global histogram analyses of (a) whole-brain tractography results and (b) skeletonized WM masks. In addition to the FA and MD, the planar diffusion coefficient (CP) was computed as it can provide more specific information of the complexity of the neural structure. Our main finding indicated that adults with AS had higher mean FA values than controls. A less complex neural structure in adults with AS could have explained the results, but no significant difference in CP was found. Our results suggest that there are global abnormalities in the WM tissue of adults with AS.
Autism research : official journal of the International Society for Autism Research, 2013 · doi:10.1002/aur.1332