According to American researchers, certain types of autism are linked to a different structure of the brain. Two independent teams have worked on an autism characterized by a brain whose volume is larger. For the researchers, this is a significant advance in research into this disease.
The MIND Institute at the University of California, Davis (USA) conducted a study published in the journal Biological Psychiatry on November 2, 2020. This is based on two independent research works. The first explored the brain size of autistic children and the second, to analyze the development of their white matter, the tissues responsible for the circulation of information in the nervous system. The final report describes the study of several medical images in order to follow the evolution of a child's brain over several years.
In order to achieve this feat, the researchers performed more than a thousand MRI scans on 294 children with autism from their 3 to their 12 years, as well as 135 children presenting no disorder. After viewing the images, scientists claimed that some autistic children had larger brains than others. The latter mentioned the term disproportionate megalencephaly , to be associated with a more pronounced intellectual disability.
A 2009 study had already observed that children with autism could have larger brains during the first years of their lives. However, it was believed that the size of the brain stabilized as it grew . The latest study, on the other hand, claims that 3-year-old children with autism have larger than average brains and that this is still the case by their twelfth birthday. This research also shows that autistic children with intellectual disabilities are mostly those with larger brains. In other words, when a child with autism has a brain whose size exceeds the average, the probabilities that his IQ is lower increase.
“ Larger brain size in autism has been associated with lower IQ, and children with intellectual disabilities are harder to scan as they get older" said David Amaral, co-author of the study.
Let's also mention another important observation. According to study leaders, the development of white matter in the brain differs depending on the type of autism and therefore, its severity. Thus, children with a more severe form of autism have slower development of their white matter. For scientists, their work opens the door to better care autistic children.
