Recent research at the University of Alberta has found a correlation between the white matter structure of children's brains and reading performance, suggesting that reading difficulties in children may have a neurological origin.
The research, headed by Alberta Heritage Fund for Medical Research senior scholar Dr. Christian Beaulieu, a professor in the Department of Biomedical Engineering, in collaboration with Dr. Linda Phillips from the U of A Centre for Research on Literacy, used an advanced magnetic resonance imaging (MRI) technique known as diffusion-tensor MRI to determine which brain structures are correlated with reading ability. The research was funded by the Canadian Language and Literacy Research Network and was published in the May issue of NeuroImage.
"All of these complex cognitive tasks involve multiple areas of the brain. A common way of looking at the brain for cognitive tasks is a technique known as functional MRI, where you look at the outside part of the brain and the neurons and see which ones 'turn on' when you read or perform a task," said Beaulieu. "There are these structural signatures in the brain that relate to how well a person can read."
Beaulieu and his research group conducted their study on 32 children aged nine - 12 and looked into their reading ability as well as their white matter patterns. White matter comprises the bulk of the deep parts of the brain and is responsible for information transmission, whereas grey matter is responsible for information processing. Researchers have long suspected that white matter pattern is indicative of reading performance.
"Also equally important during reading is that different parts of the brain need to communicate and the way they communicate is through these white matter tracks of the brain. The white matter is basically the wiring in the middle," said Beaulieu.
"The way I see it, the grey matter is the computers and the white matter is the wiring or the Ethernet cable that connects them all up and lets them communicate."
The researchers concentrated their study on the "wiring" that connects different parts of the brain and observed that measurable differences in the wiring can be found in children with reading disabilities. They found that the stronger the connectivity of the white matter "wiring," the better the child's reading ability.
According to Beaulieu, the area of the brain related to reading difficulties is located in the left hemisphere, in the temporal-parietal white matter. It is also possible that it's related to the nearby Broca's area and Wernicke's area, both of which are known to control language comprehension and interpretation of speech.
A previous Stanford University study found consistent differences in white matter integrity between dyslexic adults and adults who can read well. Beaulieu and his team built upon this research and extend the focus to children because the relationship between reading difficulties and white matter integrity is akin to the chicken-and-egg argument - it's hard to determine if white matter differences are the cause or the result.
"With the adult study, you didn't know if the white matter difference was the cause of the reading problem in dyslexic adults or if this was due to adult dyslexics not reading their whole life and they just lose this connection," said Beaulieu. "So by looking at younger and younger children, we can work backwards and start to rule out the latter and we can figure out if this is the cause or the symptom of the problem."
Based on the results of this research, Beaulieu is inclined to believe that reading disabilities are likely to be caused by problems in white matter integrity, though more research in children of younger age groups is necessary to support that. While the data from this research suggested there could be a neurological cause for reading difficulties in children, Beaulieu said this is not a perfect diagnostic tool for dyslexia.
"What we're looking at are subtle differences and I don't think it'll become a diagnostic tool. But it will help us better understand what might be contributing to the problem and this might lead to better intervention and see if intervention has an effect in that particular area of the white matter," he said.
"Everybody develops at a different rate. We know that white matter certainly changes over time with the development of the brain and even into the teens and young adulthood. There is still room for changes as a person ages."
Beaulieu is currently looking for healthy boys aged 11 - 16 for an MRI study of brain development. Volunteers will undergo an MRI scan for 20-30 minutes. Parental consent is required. Interested parties may contact Dr. Beaulieu at 492-0908 or Lindsay at [email protected] for more details.
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