Millions of children around the world suffer from learning difficulties, which include dyslexia and language processing disorder, and are linked to conditions like dyspraxia, ADHD, and autism spectrum disorder (ASD). It’s long been thought that specific learning difficulties can be traced to specific regions of the brain, but now, a study published in Current Biology has thrown doubt on this assumption, suggesting that learning difficulties are instead the result of how the brain is wired.
It’s estimated that between 14 and 30 percent of children and adolescents worldwide have learning difficulties severe enough to require additional support. But the root of these difficulties and their associated conditions have long been hazy, and studies have generally focused on one specific diagnosis, like autism or ADHD (attention deficit hyperactivity disorder).
To find out more, a team from the University of Cambridge collected data from hundreds of children with learning difficulties. They then fed the data from nearly 500 kids into an artificial neural network, which worked out that different children had different cognitive profiles. The team then used a method called “cross-profiling” to determine that these profiles were connected to learning difficulties. In addition to cognitive information, the neural network examined images of the children’s brains.
The researchers only found a weak relationship between cognitive and brain profiles, suggesting that children with one specific cognitive difficulty don’t necessarily have similar brains. And those kids that have similar brains don’t all suffer from the same learning issues. Essentially, brain structure doesn’t seem to be able to explain learning difficulties.
However, the researchers then turned to the brain’s wiring. They mapped the connections within each child’s brain to see how strong they were. Some children’s brains were wired strongly around specific “hubs” in the brain, while others weren’t. The team found that the “hubbiness” of a child’s brain was strongly connected to their cognitive profile. Children with poorly connected brain hubs were more likely to have learning difficulties. So, it seems that learning difficulties aren’t so much to do with specific regions of the brain, but rather how the brain is wired up.
However, it’s still unclear whether differences in brain connection are actually a cause of learning difficulties, and more research is needed to find out.
"We know that the building blocks of brain ‘hubs’ are in place early in life, potentially even before birth," study author Dr Duncan Astle told IFLScience. "But we know little about the factors that shape their emergence over childhood. That’s what we want to learn about next. My hunch is that the brain wiring differences might be both cause and consequence of the learning difficulty. That is, some initial differences in organisation become reinforced over childhood, partly as a consequence of the child’s experience. Small initial differences in brain organisation snowball. But we need a lot more research before we know for sure."
The findings suggest we need a rethink when it comes to how we look at the link between the brain’s structure and learning difficulties, and how we view specific diagnoses.
“One of the key findings from the paper is that a child’s diagnostic ‘label’ does not correspond well to their cognitive difficulties," said Dr Astle. "So whilst diagnosis is an important milestone for children and families, the ‘label’ itself shouldn’t dictate the kind of support they receive. That is important, because at the moment support is mainly linked to diagnosis.”