Summary: Children with a developmental language disorder have less myelin in parts of the brain associated with the acquisition of rules and habits, as well as in brain areas associated with language production and understanding.
Source: University of Oxford
Developmental language disorder (DLD) is an extremely common disorder, affecting about two children in every grade.
Children with DLD struggle to understand and use their native language, facing problems with grammar, vocabulary, and conversation.
Their language difficulties greatly increase the risk of having difficulties learning to read, of having poor academic results, of being unemployed and of facing social and mental health problems.
In research published in the journal eLifeDr. Saloni Krishnan and his colleagues used MRI brain scanners that were specifically sensitive to different properties of brain tissue.
For example, the scans measured the amount of myelin and iron in the brain. Myelin is a fatty substance that wraps around neurons and speeds up the transmission of signals between areas of the brain. It’s like the insulation around electrical cables.
Research has shown that children with DLD have less myelin in the parts of the brain responsible for acquiring rules and habits, as well as those responsible for producing and understanding language.
Dr Krishnan (Reader, Royal Holloway, University of London), who led the study as a researcher at Oxford University, says that “DLD is a relatively unknown and understudied condition, unlike the conditions better-known neurodevelopmental disorders such as ADHD, dyslexia, or autism. This work is an important first step in understanding the brain mechanisms of this disorder.
Lead author Kate Watkins, a professor of cognitive neuroscience at the University of Oxford, says, “This type of analysis tells us more about the make-up or make-up of brain tissue in different areas.
“The findings could help us understand the pathways involved at the biological level and ultimately allow us to explain why children with DLD have problems learning language.”
More studies are needed to determine if these brain differences cause language problems and how or if language difficulties might be causing these changes in the brain.
Further research could help scientists find new treatments that target these brain differences.
About this language development research news
Original research: Free access.
“Quantitative MRI reveals striatal myelin differences in children with DLD” by Saloni Krishnan et al. eLife
Quantitative MRI reveals striatal myelin differences in children with DLD
Developmental language disorder (DLD) is a common neurodevelopmental disorder characterized by difficulties with receptive or expressive language or both. While both theoretical frameworks and empirical studies support the idea that there may be neural correlates of DLD in frontostriatal loops, results are inconsistent across studies.
Here, we use a new semi-quantitative imaging protocol – multiparameter mapping (MPM) – to study microstructural neuronal differences in children with DLD.
The MPM protocol allows us to reproducibly map specific indices of tissue microstructure. In 56 typically developing children and 33 children with DLD, we derived maps of (1) longitudinal relaxation rate R1 (1/T1), (2) transverse relaxation rate R2* (1/T2*) and (3) magnetization transfer saturation. (MTsat). R1 and MTsat primarily index myelin, while R2* is sensitive to iron content.
Children with DLD showed reductions in MTsat values in the caudate nucleus bilaterally, as well as in the left ventral sensorimotor cortex and Heschl’s gyrus. They also had lower R1 values overall. No group differences were noted in the R2* cards. Differences in MTsat and R1 coincided bilaterally in the caudate nucleus.
These results support our hypothesis of corticosteroid abnormalities in DLD and indicate abnormal myelin levels in the dorsal striatum in children with DLD.