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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."
What I got out of the article was not that 'scans could allow early detection and diagnosis', because deploying brain-scans on children to 'detect' a disorder like this is ludicrous (due to the low base rate and high cost of imaging). What I got was that there are 'pre-reading tests' which are apparently useful to detect dyslexia - otherwise you couldn't correlate the brain imaging results with the results of those pre-reading tests, and then call the imaging a 'dyslexia test' right?
Hell, maybe the researchers could develop a battery of pre-reading tests and then look at the correlation of the tests to the smaller arcuate fasciculus to choose good diagnostic tests. Assuming that the smaller arcuate fasciculus is actually causal in dyslexia, of course.
(Note: I am broadly cynical about correlational brain imaging research such as this. It can be good. It is almost invariably overstated.)
My dyslexia forced me to work harder in school at things others found easy. I was confused for a few years until I realized not everyone had my issues. Once I adapted, I started jumping grades and moving ahead. There are things about it that can be leveraged in terms of learning, after all.
Finding issues like this out early can be a blessing or a curse depending on how the parents and the school system react. If it's used to hang a 'problem learner' sign on a kid and just stick them in a corner, I say it's a curse. If it's used to support a tailored teaching environment, it would be a blessing.
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.
i don't know karate, but i know ca-razy