Brain activity pattern signals ability to compensate for dyslexia
Brain scans of dyslexic adolescents who were later able to compensate for their dyslexia showed a distinct pattern of brain activity when compared to scans of adolescents who were unable to compensate, reported researchers funded in part by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Akinso: Brain scans of dyslexic teens showed a pattern of brain activity when compared to scans of teens that were unable to compensate for their dyslexia according to a Eunice Kennedy Shriver National Institute of Child Health and Human Development study.
Miller: The key aspect of the project really had to do with whether the collected brain measures could provide insight above and beyond behavior measures that tell us about a person's reading skills.
Akinso: Dr. Brett Miller is a Health Scientist Administrator at the NICHD.Miller: In addition to these behavioral test the reading, and language skills that were taking when they came in. The researchers also had the adolescents complete some reading related task while monitoring brain activity.
Akinso: The researchers used two types of brain imaging technology to conduct their study. The first, functional MRI which depicts oxygen use by brain areas involved in a particular task or activity. The second, diffusion tensor magnetic resonance imaging (DTI), maps the brain's wiring, revealing connections between brain areas. Dr. Miller explains what researchers found when teens were scanned using the functional MRI.
Miller: The functional MRI or the fMRI scans of the adolescents without dyslexia just as a contrast point. Essentially those that were reading normally showed strong brain activation pattern on the left side of the brain when completing the reading task inside the MRI scanner. To contrast that those individuals who had dyslexia, their brain scans revealed relatively weak activation patterns on the left side of the brain in regions that are commonly activated during reading. But what's of particular note here is that in the case of the adolescents with dyslexia who later were able to compensate for their disability, these individuals showed strong activation in the right hemisphere; inferior frontal gyrus.
Akinso: The adolescents who would later compensate for their dyslexia showed a pattern of increased activity in the brain region known as the inferior frontal gyrus, an area on the right side of the head, slightly below and behind the temple. Similarly, DTI scans of the brain also revealed stronger connections in the right side according to Dr. Miller.
Miller: The DTI scans for the group that was able to compensate for their reading disability showed a strong network of connections again of the right side for a region called the superior longitudinal fasiculus.
Akinso: The superior longitudinal fasiculus is a network of neural fibers linking the front and rear of the brain. The fibers are involved in the processing of visual aspects of text. This brain area governs the ability to halt an ongoing activity. The adolescents were shown pairs of printed words, and asked to identify pairs that rhymed. Dr. Miller says the individuals with dyslexia that didn't compensate for their disability had continued difficulty in a range of reading and language measures.
Miller: They didn't show the same pattern of this right hemisphere activation in the inferior frontal gyrus and nor did they have the strong pattern of connectivity in the superior longitudinal fasculus. More generally they showed relatively weak activation at least compared to individuals without dyslexia and the reading related regions of the left hemisphere.
Akinso: Dr. Miller says their findings suggest that brain imaging may help determine when a treatment is likely to be effective or which patients are most susceptible to risks. For more information on this study, visit www.nichd.nih.gov. More on dyslexia can be found at www.ninds.nih.gov. This is Wally Akinso at the National Institutes of Health, Bethesda, Maryland.
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Reporter: Wally Akinso
Sound Bite: Dr. Brett Miller
Topic: Parkinson's disease, pesticides
Additional Info: Brain activity pattern signals ability to compensate for dyslexia