Researchers from MIT have discovered a link between the size of a language-processing area of the brain and poor pre-reading skills in kindergartners. This finding, coupled with an MRI technique, could lead the way for an earlier dyslexia diagnosis.
The study, published in the Journal of Neuroscience, relies on previous research showing that adults with poor reading skills have a smaller, less organized arcuate fasciculus.
According to researchers, this structure of the brain connects two areas integral to communicating: Broca's area, involved in speech production, and Wernicke's area, involved in understanding both written and spoken language.
Until this recent study, it was unknown whether the differences in the arcuate fasciculus were the cause of reading difficulties or the result of little reading experience.
Part of a larger effort that analyzes 1,000 children at schools in Massachusetts and Rhode Island, the study from Massachusetts Institute of Technology (MIT) involved researchers assessing children at the start of kindergarten for pre-reading sounds. This gave them an idea of where each child's pre-reading skills lay.
Following this assessment, the researchers then invited some of the children to MIT for brain scans that use a technique called diffusion-weighted imaging, a MRI (magnetic resonance imaging).
The study published in the Journal of Neuroscience utilizes brain scans from 40 children.
Phonological skills and dyslexia
Upon comparing the brain scans with results of pre-reading tests, the researchers noticed a link between the size and organization of the arcuate fasciculus and performance on phonological awareness tests.
Phonological awareness refers to the ability to identify and employ the varying sounds of language. This ability, the researchers note, can be measured by observing how children segment, identify and rearrange sounds to make them into new words.
Elizabeth Norton, one of the lead authors of the study, says: "The first step in reading is to match the printed letters with the sounds of letters that you know exist in the world."
The researchers add that since the arcuate fasciculus connects Broca's area and Wernicke's area in the brain, a larger and more organized one could help the two regions communicate better. It could link both speech production and the ability to understand written or spoken language in a more efficient way.
For senior author John Gabrieli, the study introduces a question:
"We don't know yet how it plays out over time, and that's the big question: can we, through a combination of behavioral and brain measures, get a lot more accurate at seeing who will become a dyslexic child, with the hope that that would motivate aggressive interventions that would help these children right from the start, instead of waiting for them to fail?"
The researchers conclude that for some dyslexic children, offering early training with phonological skills can help with their reading skills later on.
This latest study builds on a 2011 study, also from MIT, which revealed that phonological impairment could cause dyslexia.