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Unscrambling Dyslexia

New research shows that different patterns of brain activity may account for the neurological disorder known as dyslexia. Phil Ponce asks the experts to discuss the findings.

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  • PHIL PONCE:

    Now, there's been new research that people with dyslexia actually have different patterns of brain activity than people who are good readers. To explain those findings and their implications, we're joined by Dr. Sally Shaywitz, lead author of the study, which was published in the Proceedings of the National Academy of Sciences. She's a professor of pediatrics at the Yale University of Medicine. And Reid Lyon, head of child development and behavior at the National Institute of Child Health & Human Development, that's part of the National Institutes of Health. And welcome both. Dr. Shaywitz, what did your study find?

  • DR. SALLY SHAYWITZ:

    Well, since dyslexia was first described over a hundred years ago, we've learned a great deal about reading and reading difficulties, in particular, we've learned that in order to learn to read a child must develop an awareness that the spoken word is made of smaller units of sounds, and that letters represents these sounds. Based on this knowledge, we examined two groups of people: a group of good readers and a group of dyslexia readers. And we found significant differences in brain activation patterns as each of these individuals performed a series of reading tasks.

  • PHIL PONCE:

    And tell us specifically how you went about finding out that there's different ways that the brain works in people who have dyslexia, opposed to people who can read well.

  • DR. SALLY SHAYWITZ:

    We used a remarkable new technology termed functional magnetic resonance imaging.

  • PHIL PONCE:

    Is that like a regular MRI?

  • DR. SALLY SHAYWITZ:

    Well, it is and it isn't. It is in terms of the basic hardware that's used is the same if you have a headache or a knee injury and you have an MRI. But that normally that MRI only lets you see the structure. It doesn't let you see the brain in action.

  • PHIL PONCE:

    And what did this MRI show you?

  • DR. SALLY SHAYWITZ:

    This MRI showed us what we did was ask each of these people to identify letters, to sound out letters, and then to sound out words. And what we found, as we looked in the brain, we found a pattern of activation in the back of the brain as good readers sounded out letters and words. A whole region in the back of the brain became active.

  • PHIL PONCE:

    So here we're looking at a chart that sort of summarizes those findings that in the normal brain you talked about the pattern of activation. That means the level of brain activity. And we see that there's some–there's activity in the back and also in the front, but in the dyslexic readers, what do we see?

  • DR. SALLY SHAYWITZ:

    We see a very different pattern. We see a pattern of relative under activation in the back of the brain and we see a pattern of over activation in the front of the brain. And what we believe is this pattern of relative under activation in the back of the brain, coupled with relative over activation in the front of the brain, may represent a neural signature for the reading difficulties experienced by dyslexic readers.

  • PHIL PONCE:

    So there is a telltale pattern that good readers exhibit that dyslexic readers do not.

  • DR. SALLY SHAYWITZ:

    Exactly.

  • PHIL PONCE:

    And do you think that's–you think that gives you a key as to the cause of dyslexia?

  • DR. SALLY SHAYWITZ:

    Well, I think these findings have several important implications. I think from the perspective of scientists, this confirms what we've learned from reading tests and language tests, but the difficulty occurs when people with dyslexia have to try to sound out words, get to the sound structure of words. And I think what this does is for the community of scientists that have been dedicated to studying dyslexia, it tells us where to shine the light. It tells us which system is involved, which system is disrupted.

  • PHIL PONCE:

    But right now there's–is there any answer as to why people with dyslexia tend to use that front part of the brain?

  • DR. SALLY SHAYWITZ:

    Well, that's an interesting question, and that's a subject of future research. Indeed, there are investigations currently going on to address just that question.

  • PHIL PONCE:

    Mr. Lyon, why is this study significant?

  • REID LYON:

    For a number of reasons. Number one: if you don't learn to read, you don't make it in life. The NIH has aggressively pursued research and supported research to try to understand three things: what does it take to learn how to read, if you don't read well what gets in the way, and the most practical aspect, if you don't read well, what do you do about it. Sally's study in the Yale group goes after the first two questions. What does it take to read? As Sally has mentioned, we've been able to identify that reading requires an understanding that words are made up of sound parts that will be applied to print. That's how one deciphers the code in reading. This study also shows that there is a neurobiological underpinning for the difficulty the kids show us. Their reading is slow, labored, hesitant, and primarily because they do not map these sounds well on to the print, this study indicates clearly that there are neurobiological features that explain that.

  • PHIL PONCE:

    And this–my understanding is this is the first map of a so-called reading path in the brain, is that correct?

  • REID LYON:

    Well, it converges on a number of other studies quite nicely. This one is more complete and showing what we consider the most comprehensive system. What this study also does by applying a non-invasive camera, if you will, a non-invasive technology, is it allows us to study children, as well as adults. Sally's group and other groups now are working on trying to understand a very critical question. If you don't learn to read, and we can get to you early enough, with the right kinds of intervention, as you gain in your reading capabilities, what happens to the brain? How does the neurophysiology change as well? And these findings are going to give us significant understanding about how plastic the brain is, how young kids have to be in order to receive optimum kinds of gains, whether intervention is applied at five and six years of age are equally robust at 10, 11, and 12 years of age. And does the brain have something to say about that with respect to how open or malleable it might be to respond to the intervention.

  • PHIL PONCE:

    Dr. Shaywitz, how important is it to have some tangible evidence that dyslexia actually exists?

  • DR. SALLY SHAYWITZ:

    Well, I think it's incredibly important. Dyslexia is referred to as a hidden disability. And what that means is there's no external sign that someone can point to and say that's the source of the difficulties. You know, if you break your arm, you can have an x-ray and point to it and say, "Ah, there's the fracture, there's the source of the difficulty." What often happens is that young men and women who are dyslexic, sometimes the brightest young men and women, they work very hard, and they accomplish a lot, but they have difficulty reading, and then they're told, well, it must be you're not trying hard enough; maybe you're not motivated enough, or maybe it's your imagination. So what these findings do, it allows these individuals to point to these brain activation patterns and say, look, here's the evidence, here's the concrete proof of the neurobiologic evidence nature of dyslexia.

  • PHIL PONCE:

    And Reid Lyon, what does one do with this proof in terms of coming up with better treatment for people with dyslexia?

  • REID LYON:

    Well, part of the NIH program is clearly devoted to trying to figure out what in the world we can do. We now understand that the sound issue, these phoning issues that Sally's study has identified–

  • PHIL PONCE:

    –referring to–

  • REID LYON:

    The sound structure that is difficult for the youngsters, that is, in the brain scans that Sally has shown you those brain regions that should help kids understand that words are made of sound are under activated. The task of the teacher is to make sure the youngsters develop that sound capability so that they can then map the sounds on the letters that they see.

  • PHIL PONCE:

    So they can make a connection between what they hear and what they see on the written page.

  • REID LYON:

    That's correct. We're working very hard to see which kids respond to which kinds of teaching methods to increase reading behavior, but we are now clear that what the Shaywitz study has identified has to be improved in order for accurate and good reading to take place. It's not something which can circumvent in order to produce robust reading in children with difficulties.

  • PHIL PONCE:

    Dr. Shaywitz, if one is a parent of a child with dyslexia, what should he or she take away from the study?

  • DR. SALLY SHAYWITZ:

    Well, I think there are several things. One is that reading difficulties are real. They have a neurobiologic substrate. But I think even more than that, these differences emerged when these dyslexic individuals were trying to get to the sound structure of the written word. That tells us this is where the prime difficulty is. And that will direct us to, in terms of trying to improve someone's reading ability, to try to bring up that level of awareness so that children develop an understanding that words are made of sounds and that the letters represent these sounds. There have been some wonderful studies carried out through NICHD that have indicated already that if you use these principles, teaching children about the basic nature of language, reading really improves. It makes a real difference.

  • PHIL PONCE:

    Dr. Shaywitz, Mr. Lyon, thank you both for being here.

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