Tuesday, July 28, 2009

The cognitive neuroscience of dyslexia and its repair

John Gabrieli offers a review article in the July 17 issue of Science. Several clips:

Reading is essential in modern societies, but many children have dyslexia, a difficulty in learning to read. Dyslexia often arises from impaired phonological awareness, the auditory analysis of spoken language that relates the sounds of language to print. Behavioral remediation, especially at a young age, is effective for many, but not all, children. Neuroimaging in children with dyslexia has revealed reduced engagement of the left temporo-parietal cortex for phonological processing of print, altered white-matter connectivity, and functional plasticity associated with effective intervention. Behavioral and brain measures identify infants and young children at risk for dyslexia, and preventive intervention is often effective. A combination of evidence-based teaching practices and cognitive neuroscience measures could prevent dyslexia from occurring in the majority of children who would otherwise develop dyslexia.

Brain activation differences in dyslexia and its treatment. Functional magnetic resonance imaging activations shown on the left hemisphere for phonological processing in typically developing readers (left), age-matched dyslexic readers (middle), and the difference before and after remediation in the same dyslexic readers (right). Red circles identify the frontal region, and blue circles identify the temporo-parietal region of the brain. Both regions are hypoactivated in dyslexia and become more activated after remediation.


hayesatlbch said...

"often arises " "is effective for many, but not all," " preventive intervention is often effective."
"could prevent dyslexia from occurring in the majority of children"

I couldn't agree more. The majority of research effort is indeed in those areas because it is hopeful for a majority of dyslexics.

"Not for all dyslexics" "non trivial amount of non responders"
" lack of effort to identify non phonological problems" would generally also be fair descriptions of phonologically based dyslexia research.

My niche is helping a minority of dyslexics that can describe visual problems that make reading difficult(visual dyslexia). Visual problems are unlikely to respond to phonological interventions . When coexisting with phonological problems, visual problems can inhibit the phonological interventions to the degree that they add to the reading problems.

I infer ( not from this post)a lack of research funding to address the minority on dyslexics that are non responders to phonological interventions. Where funding exists studies result or it may just be a matter of lack of glory.

I applaud the reviewer for fairly using modifiers to express the non universality of phonological problems as the cause of dyslexia as many articles read as if the phonological problems are not only the universal cause of dyslexia but that phonological interventions are the universal solution.

I look forward to the day when dyslexia is thought of as a syndrome ,which I believe it is, as that should expand dyslexia research into a multi-deficit search rather than the steady focus on phonological problems. only.

William Lu said...

I find this study particulary relevant to my work with adults with dyslexia. I have seen significant improvement in a few of my patients after only have several months of treatment. I can't help but think that the same remedial neurobiological process taking place within these children are also taking place in the adults I work with. This may be an interesting study to persue in the future.

Causes dyslexia said...

Dyslexia is a neurological development disorder. The symptoms are clear but there is no proper medication found on it. It is also found in children. There are many big personalities also who suffers from dyslexia. Kinesis and Eurythmics has proved effective.

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