Dyslexia Decoded in the Brain

By Breanna Draxler | December 5, 2013 1:00 pm
3d dyslexic brain

3D image of a dyslexic adult brain from the study. Image credit: KU Leuven, University of Leuven

Dyslexia affects about one in ten people of all ages, inhibiting their ability to read and spell. In our language-driven world, that’s a real problem. Researchers have long debated the brain basis of the condition, and a new study provides a pretty convincing answer.

Language is built of little individual sounds called phonemes. During language development, the brain learns how to identify these sounds and distinguish between them, correcting for variations in tone, accent, etc. Then the brain must learn how to arrange these individual pieces into very specific combinations called “phonetic representations.” This is where the breakdown is thought to occur in the dyslexic brain. As described in Science,

For the past 40 years, researchers have thought that people with dyslexia don’t develop precise “phonetic representations” and thus can’t recognize fine distinctions in language. The distorted representations, like smudged words in a dictionary, might not be evident in everyday speech, but they could make learning to read and spell quite difficult, especially for words that don’t follow obvious spelling or pronunciation rules, such as “bough” and “cough.”

Does Not Compute

So the decades-long debate has been this: are the brains of people with dyslexia unable to develop these representations, or are they just unable to access them? In other words, does the breakdown occur in the brain’s processing or its internal communications?

This study was designed to find out.

Researchers used fMRI to take 3D pictures of the brain activity of 23 adults with severe dyslexia and 22 without. Participants listened to a series of nonsense words spoken with different intonations. Each word was made up of alternating consonants and vowels, like “baba,” “dada,” and “dydy.” With each new word, the task was for participants to identify the difference between it and the previous word in the series—Did the consonant change? The vowel? Or both?

The Dyslexic Brain

When the scientists analyzed the patterns of brain activity and connectivity they found that dyslexic individuals’ brains were able to process the words as well if not better than the controls, but they were 50 percent slower at responding. This appears to be due to poor coordination between their auditory cortices (the areas responsible for processing basic phonemes) and their Broca’s area (the region that processes higher-level language). The weaker the connection between these two regions, the slower the individual’s response.

It’s too early to tell whether this study finally settles the debate over dyslexia’s brain basis, but the researchers are hopeful that it is at least a step toward understanding and therefore treating dyslexia. The study, published in Science, suggests that perhaps someday electrical stimulation of the brain could provide a therapeutic treatment for people with dyslexia.

CATEGORIZED UNDER: Mind & Brain, top posts
  • whatgoeson

    Aren’t we electrically overstimulated as it is, with radio, tv, interwebs, and smartphones? What if all the stimulation makes you overtaxed, stressed, and frankly, dumber? How many times do you shock the monkey, before he gets convulsions and dies? Maybe, ‘dyslexia’ is just people being regular normal people that just don’t test high on some government test.

    • marina marinova

      A bit simplistis, as dyslexia and its ‘sister’ legasthelie, have been around for ages. A number of world-famous artists (including da Vinci) are suspected to have had the condition.
      Of course, it may be debatable to what extent this is an ‘illness’ that needs treatments snd not just a personality feature. The debate is going on for Asberger and milder forms of autism as well.
      The question that we may ask is, whether Broca’s poor connection is not ‘compensated’ by betther-than-average connection of other brain areas, which would make those people great artists, musicians, mathematicians. If that’s the case, wouldn’t dyslexia treatment ‘average down’ a talent elsewhere?
      Given a fair chance to process information their way, a number of dyslexic people manage school and university remarcably well. Why give them the feeling of being ‘wrong’ just becsuse some primary teschers cannot see beyond correct spelling?

      • Artlexia

        Touche’ – says this Dyslexic artist.

      • whatgoeson

        Maybe someone with Asburger syndrome just plain thinks differently, and ‘normal’ isn’t ‘all that’ by any stretch of the imagination. If there even is a syndrome. Do you know what the ‘cure’ for ADD/ADHD is? Amphetamine, and methamphetamine. Seriously. Research that action online.

        No two people in this world think alike, and thank Deity for that, or we’d all be wearing red armbands for sure. I think there’s too much dogmatic adherence to stuff that gets written in medical texts, and at the end of the day, insufficient allowance made for the fact that people aren’t perfect, we’re not naturally born data processors, working with information is a learned skill, sometimes learned involuntarily, and things like math, the arts, sciences, you’re working with a lot of information, there.

        Spelling: Know the code. Language is a code. Once you learn the code, you can decipher something called a ‘book’, and once you can do that, new doors to learning will start to magically open. Whether or not you choose to walk through them, is up to you.

        I think the real fear among the medical and academic communities, is having unrecognized(unregistered?) geniuses rolling around, people that can figure out their ‘stuff’ without too much problem, and some members of those communities frankly being uncovered as frauds. Just sayin’ Those people in the furry sweaters and lab coats aren’t near as smart as they might like to think they are..

    • WhereRUFrom?

      Why can’t we spell Asperger’s syndrome correctly?

  • Jill McGlaughlin

    I have 2 children(ages 7 and 9) with Dyslexia and the problem is not that they have Dyslexia, the problem is the schools do not know how to properly identify and offer an adequate remediation program. They are being taught, by a private tutor, how to ready using the Orton-Gillingham method and the are successfully learning how to decode the English language. It will take them longer to process the written language but they can and will do it.

    I do not like the idea of electrical stimulation as a treatment.

    • marina marinova

      That’s one of the biggest problems. Teachers, especially primary teachers all over the world don’t seem to get proper training / education when it comes to children with dyslexia. It’s ever so tempting to stygmatize them as ‘stupid’ and ‘not really making an effort’. Dyslexic children just have a limitation in one particular field – other kids can’t run fast, can’t draw, can’t process music, a poor at maths, science etc. As long as they have at least one subject they’re really good at, that’s generally good enough to help them make it through school and may be even university. Dyslexia is one of the few limitations that seem to obliviate children’s other talents and abilities. True, primary education is largely focused on reading and writing skills and yes, they are essential for information processing, but they are never the solitary skills a child’s ‘value’ and, indeed, self-esteem should be based upon. I honestly sometimes have the feeling that just because teaching to read and write (to an average kid!) is the only skill some primary teachers possess, they see children through the highly distortive prism of ‘ability to be (easily) taught to read and write.
      Best of luck for your kids. I’m sure they’ll manage and hope they’ll be allowed to flourish in the fields where there true talents lie.

    • Marilyly L’éveil

      It might seems heavy, but we use this kind of treatment when we are going to the physiotherapy. It works almost the same. This kind of treatment has been administrated to aphasic patients and they did improvements like never before. But I understand how barbar it seems and the reticences, specially if your kids are improving well with another method :)

  • Axes2

    The world will just have to pardon my lesdexia.

    • marina marinova

      Nice! In fact the world shouldn’t walk around believing there’s something to be pardoned. :-)

  • Leon Bird

    I am a 67-year-old dyslexic and mom my dyslexia has caused some problems particularly in grade school and high school (I failed Spanish one twice even though I put a lot of effort into it) the different way of thinking that comes from being dyslexic has helped me in college and in life. When I look at my life and if I would’ve had the choice to go back and not be dyslexic I would not take it. It’s the differences in our ways of thinking that motivate and move society forward.

  • Marilyly L’éveil

    If dyslexia is a result of a poor connexion between the auditory cortices and the Broca’s area, they should be able to perform as good as normal patients on their writing performance, just with a little bit more time. The truth is that it is not always the case. I believe dyslexia is much more than just a language impairment and I can’t wait to see studies about the working memory of dyslexics and their capacity to abstraction… Based on my short experiences, dyslexic kids do not only confuse phonemes, but also some very abstract words, such as left and right, colors, numbers, some similars tools as forks and spoon, etc. They also have difficulty to process many instructions if they were given at the same time… My opinion is that language impairment in dyslexia is only a symptom of a more deep deficit in the cognition.


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