Study Peeks Into the Brain Wiring Behind Dyslexia
A new study using neuroimaging to explore the brains of dyslexic individuals has detected out-of-sync processing in the four brain regions known as the ‘Reading Network.’ The more out-of-sync the processing was, the greater the reading difficulty of the children scanned.
The research team says its findings could inform audiovisual tests that could diagnose dyslexia in children at an earlier age.
Dyslexia, the most common learning disability, affects 10 to 15% of all children — and possibly more, in India, due to the commonness of multilingualism, which can exacerbate reading difficulty. Currently, dyslexia in children is typically diagnosed only after they experience academic difficulties in primary school. “Until these kids with dyslexia are lagging so far behind their peers, there’s no way to reasonably assume that they’re not part of a continuum of ability, but rather a separate group altogether,” said study leader Chris McNorgan, PhD, an assistant professor of psychology with the University at Buffalo, US. This often sets children on a path of consistent academic lagging, which can spin into emotional and behavioral issues, as frustration and stigma mounts — especially in resource-poor school environments.
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McNorgan and team’s findings build on and confirm previous studies that have found dyslexia is only related to wiring quirks in brain regions responsible for integrating audio and visual information, wiring which does not affect general cognition or intellect. Their findings also clarify that these wiring quirks aren’t only about strength of connection between the regions of the Reading Network, but about how coordinated the connections are when they fire up.
“To think of the ‘manner’ of connections, by way of analogy, as being separate from ‘strength,’ a city planner trying to optimize traffic flow is probably not going to be successful by just dropping a multi-lane highway down the middle of a city if the neighborhoods and other city streets are not organized in a way that can take advantage of the extra traffic capacity,” McNorgan explained.
While McNorgan describes the team’s findings as “notable,” he described them as a means to improving screening and support, not for explaining the underpinnings of dyslexia. “Why some children’s brains seem to be resistant to becoming optimally wired remains an outstanding question,” he said.
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Research out of India might be helping explain the latter unanswered question. Last year, Indian scientists reported identifying a cluster of genes with mutations that correlated strongly with dyslexia. “There variations were present in the members of the family with the disability as opposed to those with normal reading abilities. More importantly, these variations are inherited as a single block,” Subrata Sinha, of the National Brain Research Centre (NBRC) in Manesar, told The Hindu at the time. However correlation is not causation, and the cluster of genetic mutations, while promising, has yet to be confirmed as the root cause of quirky wiring in the audiovisual processing regions of the brain.
Until that’s more fully parsed, here’s hoping greater insight into the way brains are wired for dyslexia allows kids better support in overcoming their difficulties.