HomeLearning DifficultiesLearning Disabilities & ADHDReading

How brain research can help demystify dyslexia

How can brain research tools help us understand dyslexia, fine-tune its identification, and improve teaching methods?

By Gordon Sherman, Ph.D.

Neuroscientific tools, such as neuroimaging, promise to play a key role in the unfolding story of dyslexia - helping to clarify misconceptions, dispel controversy, and improve diagnosis and intervention.

Dyslexia results from a complex gene-environment interaction that begins in the womb and eventually modifies both the structure and function of the nervous system. This prompts the brain to develop according to a different blueprint. The result is a brain that does not process language in the usual way. Even with all we understand about this atypical development, mysteries remain.

Controversy and Confusion

Why do controversy and confusion often surround dyslexia? Partly because the work of the researchers, educators, and evaluators concerned with dyslexia often rests on inference - inferred assumptions about normal and atypical brain development and function.

Historically, to investigate the structure and neurophysiological function of brains, neuroscientists rely on the examination of brains obtained at autopsy or on studies of patients during neurosurgery. To understand learning and learning disabilities, clinicians and educators rely on closely observed behavior patterns. Scientists, clinicians, and educators study neural tissue or behaviors to infer what the brains of their patients, subjects, or students actually do in normal living and learning conditions.

Given the inexact nature of inference, many conclusions about dyslexia are subject to interpretation, and, thus, plagued by controversy. Since Pringle Morgan and James Hinshelwood first described dyslexia a little over 100 years ago, scientists, educators, and clinicians have debated dyslexia's definition, diagnosis, treatment, and even its existence.

Now, however, the brave new world of neuroimaging promises to put many dyslexia debates to rest. Much like the Hubble telescope enables us to see into remote corners of space, neuroimaging allows us to probe the frontiers of the human brain. As neuroimaging technology progresses, we will "see" the structure and functioning of living brains with increasing clarity - a scientific advancement beyond anything Morgan or Hinshelwood could have imagined.

Modern neuroimaging techniques, showing the activity of brain areas and networks, will help unravel the mysteries of dyslexia. While traditional neurological studies and clinical observations continue to provide valuable information, neuroimaging offers a window for viewing the structural and functional attributes of living and learning brains. Thus, neuroimaging promises to enhance the diagnosis of dyslexia, the design of educational programs, and the precision of prescriptive teaching.

Neuroimaging May Aid Diagnosis

Here is the most widely accepted definition of dyslexia:

Dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge. Adopted by the IDA Board, November 2002 and by the National Institutes of Health, 2002 .

Although this definition has proven useful, particularly for research purposes, it does not give us a concrete understanding of dyslexia.

  • Exactly what is different about the brain of a person with dyslexia? What are the brain-based mechanisms for the types and degrees of dyslexia?
  • How do we diagnose dyslexia?
  • How does the environment alter brain structure and function in dyslexia?
  • What are the best methods of instruction for people with this learning disability?

Neuroimaging may lead us to a more precise definition of dyslexia, providing more specific information about its neurological basis and characteristics which, in turn, may yield additional diagnostic and educational insights.

Advanced neuroimaging tools also may aid in the diagnosis of dyslexia. Techniques such as PET (Positron Emission Tomography) and fMRI (Functional Magnetic Resonance Imaging) reveal the activity of the brain during tasks such as speaking, reading, and writing. If people with dyslexia show consistent and characteristic differences in brain function during such tasks, demonstrating a distinct "neurological profile," this information may lead to more precise identification and educational intervention.

Certainly, today's neuroimaging tools are too cumbersome and expensive, even too rudimentary, to be useful for common screening and diagnostic purposes. But who knows? Consider our remarkable evolution since Morgan and Hinshelwood. Technological advances making neuroimaging part of every child's kindergarten screening may be less science fiction than we might imagine.

Evaluating Educational Interventions

Neuroimaging also may help us discern the precise instructional elements that work best for teaching students with dyslexia how to read, write, and spell.

For example, some propose that supplementary non-language treatments directed at the visual and auditory systems benefit the struggling reader. This, however, remains controversial. It has been difficult to establish the efficacy of these approaches. Imaging the brain before and after using these techniques may provide the clues necessary to determine if they do benefit learning.

While science has verified structured-language instruction, researchers have yet to study the "multisensory" component educational therapists and teachers often include, particularly for students with dyslexia. Multisensory instruction conveys information through multiple input channels (visual, auditory, and kinesthetic/tactile) and enlists various multisensory strategies to enhance memory storage and retrieval. Multiple sensory channels feed comprehensive and concrete information to the language-processing network of the brain. Theoretically, multisensory instruction bypasses sensory-system weaknesses, conveys information to an atypical language system in more decipherable and indelible forms, and provides various "triggers" for memory.

In multisensory instruction, a student might be instructed to look at a letter (visual), listen to its sound (auditory), associate the letter and its sound with a picture of a "key word" that "unlocks" its sound (e.g., apple/short a - visual/auditory), say the letter with its sound (kinesthetic/auditory) and perhaps its key word, and write the word and perhaps move or gesture in some way that represents the key word, letter, or sound (kinesthetic). A variety of structured-language/multisensory programs employ versions of such methods, usually in inventive and systematic ways. Their goal is to achieve multiple pathways and associations for input, storage, and retrieval to offset weaknesses in sensory, language, and memory systems.

Clinical experience with this technique points to a powerful effect. From what we know about the brain and dyslexia, multisensory instruction would seem to be an important component in teaching students with this learning condition, perhaps even beneficial for all students. But science has not yet addressed the efficacy of multisensory instruction. "Seeing" the brain at work through neuroimaging may help establish the merits of this instruction and enable educators to refine its elements. Neuroimaging may help us understand the apparent magic of multisensory instruction.

What We Have Learned

Neuroimaging techniques reveal a brain far more complex than previously thought. For example, the language network appears to involve more than a few "key centers" and may be distributed in other brain regions, contrary to earlier hypotheses. We have also learned how the brains of people with dyslexia change while engaged in basic language tasks after receiving structured-language educational interventions. In general, these changes entail shifting to a more efficient, unilateral mode of processing. In other articles in this series we will discuss these remarkable findings in greater detail.

On the Threshold

Will advancements in neuroimaging dispel all the controversies and confusions surrounding dyslexia? Probably not. They will, however, bring us breathtakingly closer to understanding the mysteries of the brain. Along the way, these advancements will help us demystify dyslexia, sharpen its definition, fine-tune its diagnosis, and verify the efficacy of educational interventions. Indeed, we are on the threshold of a brave new world - one where neuroscience and education will combine to unlock and enhance human potential in powerful new ways. Morgan and Hinshelwood would have been astonished! We, however, need only a little vision to find and cross the threshold.

Comments from readers

"Gordon Sherman is arguably one of the best and dedicated researchers on dyslexia. How fortunate that he is based in Princton. "
" Hello my name is Rob Wheeldon and I’ am an adult dyslexic. I didn’t find out I was Dyslexic till I was 27 I’ am now 36. As I’ am sure you are highly aware most dyslexics have a hard time at school and I was no exception. In fact I was often told me 'I didn’t try hard enough at school and was lazy' and it didn’t help that my sister was a high flyer who came out with a masters degree and I left with nothing. I felt like a big disappointment too everyone. I loved science and history at school and couldn’t understand how I failed. However when I found out I was dyslexic I did a lot of soul searching, I went back in education with mixed results (I came out with a HND instead of a degree which feels like a consolation prize)lack of funds to continue means it may have too stay that way for a while. However I have tried too looking on the positive side. I read up about all the famous dyslexics (I never know there was so many of them). I became fascinated with Albert Einstein most of all. Now all my life I’ve been told I was thick because I was dyslexic but the more I read up about him the more I found we had in common ( poor memory, did badly at school, long periods of unemployment). So I was inspired too write a poem about him ,which I have since read out in front of a crowd of a hundred people at Sheffield’s Words aloud poetry night (there is a recording of me reading it out on their website) and it has also been read out by Annie Nightingale on Radio 1. Now if someone had told me five years ago I’d have a poem of mine read out on radio 1 I’d have thought they were having a laugh. So here is the poem I hope you enjoy it. Cheers Rob Relativity rap All the chav’s think they are real clever With their Burberry hats and eyes to close together But check Einstein he wrote the line Relativity he found divine Mass and energy is the same thing E=mc squared is da bling E equals energy M equals mass And the Mc sparks the time to pass The square root of two holds the whole thing together And the workings of this process are both elegant and clever The equation describes the speed of lights accretion And properties of mass to energy conversion From the well of gravity springs space/time The structure of which creates the world line A curved prism light gave Newton insight That the flow of quantum chromodynmics is the structural wave form which lights the planets The sun is a changeable force with a moving boundary which gives heat and light to you and me Spectral light emissions are part of the effect that curves space/ time to a constant effect With energy the world resounds there’s are always motion where light is found E and mc squared gets it together and creates all kinds of cosmic weather Photons and electrons perform the trick that lets the clockwork universe tick It is not clockwork Newton’s bucket is wrong but try making that into a song I understood Newtonian physics at school for every action an opposite I was no fool Well Dense energy equals mass they didn’t teach me that in class. Compressed energy is released in a dance a physical activity not left too chance All the sums must balance out and that’s what stars are all about Nuclear fusion will cause no confusion If you get over the simple delusion That every thing is in a fixed state That’s not how particles interrelate A black hole it has no mass Progress and motion towards its devotion No light escapes this non- Euclidian potion Into what dimension does the energy emerge The whole damn thing is truly absurd Now please don't see this as a retraction Let me illustrate this action One two three all states emerge, mass and light and energy Extend from a singularity. Unleashed potential all around and that was how the light was found The Lambda principle lets there be light who’s to say it’s not cosmologically right? A balanced creation of energy that creates everything mysteriously Electrons and photons Like to dance and will interact given half a chance With its strange polarity That exists on every scale The perfect geometry off this tale The golden ratio that makes every thing go It’s the strangest thing that we all know Too all of us its quite clear the earths a sphere You can not see the curve off the earth for its mighty girth The curve of the line resting on the equator Is the truth of the now in the past and the later? Now it all seems quite neat these marvels of science The globe travelling in relative motion and geodesic compliance But the point of an arrow that curves on a dime This is the essence of circular time, gravity curves nature too a constant degree and even time is a singularity Come on now, and don't be morons just innovate your interneurons The Wheeler-DeWitt equation freezes time But is quantum gravity the key too undoing this mystery? The Tachyon maybe faster than the speed of light and into history it sets flight I hope this rhyme found the time to show you that physics is so sublime I currently work nights as a shelf filler in a super market, but as I hope my poem makes clear I’ am capable to do so much more. I,am trying to get some publicity for my work. I want too prove too the world that dyslexic people have some thing too offer and we are not as stupid and lazy people think we are. I think work like this can change peoples attitudes too our condition. After all I am a bloke who stacks shelves who understands relativity. I often think I’am living the plot of the film 'good will hunting' I mean it’s quite funny when you think about it. Thanks again for your time Rob "
"I have a son Brandon he is 10 years old I having very hard time with him becuase School dont ant lisent about all my concerns since last years he have IEP but still dont have a very good program and gols. When they decide to put him and IEP they didin't do the MFE the base everything on the intervantions they did and one evaluation the psycology of the school did and IQ test. I take him 3 months with a private tutor and base on her experience her oponion it was he is dislexic. And after 3 months finally he learn how to read on 2nd. grade.But now he have a lot porbles with Math also but school dont want to add Math on his IEP, I also recuest last year the exteded school year program during summer but they rejected because they thing he dont needed.My concerned its he is 4th. grade and he didn't knoe his multiplication tlables because he wasn't able to understand but the school it is not worried about that. And I just tired to try to guied the school the way they can d! o part of they job. Please give me an advise! "