Dyslexia Seen In Brain Scans of Pre-School Children

dryriver writes "Brain scans may allow detection of dyslexia in pre-school children even before they start to read, say researchers. A U.S. team found tell-tale signs on scans that have already been seen in adults with the condition. And these brain differences could be a cause rather than a consequence of dyslexia — something unknown until now — the Journal of Neuroscience reports. Scans could allow early diagnosis and intervention, experts hope. The part of the brain affected is called the Arcuate Fasciculus. Among the 40 school-entry children they studied they found some had shrinkage of this brain region, which processes word sounds and language. They asked the same children to do several different types of pre-reading tests, such as trying out different sounds in words. Those children with a smaller Arcuate Fasciculus had lower scores."

Comments

Re:Excellent! There pre-reading tests for dyslexia

[mandginguero]

If you check out the actual reporting from the authors (here for abstract http://www.jneurosci.org/content/33/33/13251.abstract?sid=bb49e635-09a9-4719-8462-cf027b122652) you can see that they tested three predictors for dyslexia on children who had not yet received reading lessons. Without making any claims of observing dyslexia, they noted that the size of the arcurate fasciculus is positively correlated with scores of 'phonological awareness' and no correlation with 'rapid naming' or 'letter knowledge.' Perhaps a linguist or clinician could help elucidate what those tests are actually measuring.

It could be that dyslexia is a grouping of somewhat different brain/processing abnormalities that have similar behaviors. If that is the case, then brain imaging of the size of arcurate fasciculus could predict whether treatment aimed at increasing phonological awareness would have any effect. If you haven't had an intro neuropsych course you may not have heard that the arcurate fasciculus is a primary connection between auditory cortex and motor representations - thought to translate hearing into replying. Folk who have damage to this fiber tract are typically unable to repeat back to you what they just heard. The auditory and visual conduits run in parallel in this part of the brain, so it may have bearing on sequencing of writing, not just spoken words.