Neural correlates of language variability in preschool-aged boys with autism spectrum disorder.
In preschool boys with autism, poorer language goes hand-in-hand with altered white-matter microstructure in the inferior longitudinal fasciculus.
01Research in Context
What this study did
The team scanned preschool boys with autism using a special MRI called DTI. DTI maps the brain’s white-matter highways.
They looked at one highway, the inferior longitudinal fasciculus, and asked: does its microstructure line up with each boy’s real language scores?
What they found
Boys with weaker expressive or receptive language had altered microstructure in both left and right ILF.
The lower the language score, the more the ILF differed — a clear brain-language link.
How this fits with other research
Lo et al. (2013) saw the same brain-language coupling flip in older youths: poorer ILF structure went with weaker semantic skills. Root et al. (2017) now show this link starts as early as preschool.
Hua et al. (2024) pooled many fMRI studies and found autistic kids under-activate temporal areas during listening. The new DTI finding adds a wiring reason: the cable to those areas, the ILF, is already off track.
Chen et al. (2019) tracked speech brain-stem responses in similar preschoolers and also linked odd neural timing to poor language. Together the papers point to a chain: early brain-stem differences → ILF microstructure → later auditory cortex activity.
Why it matters
You can’t scan every child, but knowing that weak language often rides on ILF differences tells us to act early and hard. If a preschooler shows poor receptive or expressive skills, amp up auditory-language input now — the brain pathway is still plastic. Track progress with simple checklists; the same tract may also guide how fast they respond.
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02At a glance
03Original abstract
Children with autism vary widely in their language abilities, yet the neural correlates of this language variability remain unclear, especially early in development. Diffusion tensor imaging (DTI) was used to examine diffusivity measures along the length of 18 major fiber tracts in 104 preschool-aged boys with autism spectrum disorder (ASD). The boys were assigned to subgroups according to their level of language development (Low: no/low language, Middle: small vocabulary, High: large vocabulary and grammar), based on their raw scores on the expressive language (EL) and receptive language (RL) sections of the Mullen Scales of Early Learning (MSEL). Results indicate that the subgroups differed in fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) along the inferior longitudinal fasciculus (ILF) in both hemispheres. Moreover, FA correlated significantly with Mullen EL and RL raw scores, but not ADOS severity score, along the left and right ILF. Subgroups also differed in MD (but not FA) along the left superior longitudinal fasiculus and left corticospinal tract, but these differences were not correlated with language scores. These findings suggest that white matter microstructure in the left and right ILF varies in relation to lexical development in young males with ASD. The findings also support the use of raw scores on language-relevant standardized tests for assessing early language-brain relationships. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1107-1119. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.
Autism research : official journal of the International Society for Autism Research, 2017 · doi:10.1016/j.jns.2013.07.015