Study reveals neurological origins of dyslexia

Using technology to pinpoint the neurological origins of dyslexia, a team of Yale University researchers has released a study that proves dyslexia is the result of a physical miscommunication within the mind—and not the result of intellectual shortcomings that can be outgrown over time.

Nearly one in five Americans struggles with dyslexia, which prohibits the mind from recognizing the sound structures of certain words. The study’s findings suggest dyslexia is not a developmental disease, which eventually will go away, but a permanent brain disorder that educators must learn to teach to.

The study, which included 144 participants, is the largest brain-imaging experiment focused on the reading disorders of children to date. Its findings should prove useful to educators as they consider ways to improve reading under the Bush Administration’s Reading First initiative—the policy that holds all schools accountable for ensuring every student can read by the end of third grade.

“What this research shows us is a reading problem that is really, truly real,” said Dr. Sally Shaywitz, director of the Center for the Study of Learning and Attention, part of the Yale University School of Medicine’s pediatrics department. “There is a glitch in the brain.”

That glitch, Shaywitz said, is the result of a deficiency in the occipital-temporal area of the brain. Located on the back left-hand side, this is where the brain forms “neuro-replicas” of familiar words, she said.

These replicas allow students who read more easily to recognize words they have seen before, without having to sound them out on each occasion. Students who lack this function are at a disadvantage because they must rely on memory and other parts of the brain to compensate for the malfunction, Shaywitz said.

Like frustrated commuters who encounter a mid-morning detour, students with dyslexia arrive at their final destinations by taking the long way around. This redirection of neural activity slows the reading process, making it more difficult.

During the study, researchers performed individual brain scans on students while they read. According to Shaywitz, the results showed that students who had the most difficulty also demonstrated the least amount of neurological activity in that area of the brain responsible for replicating and storing learned words.

Shaywitz said the occipital-temporal area of the brain is not unlike a camera, taking pictures of words whenever it sees them. The more times the brain is exposed to a word, the clearer and more focused each stored image becomes and the easier it is for the brain to recognize what it is seeing on the written page.

For dyslexic students, many of whom have gone undetected or been wrongly categorized in the past, these findings are significant because they emphasize the need to diagnose dyslexia at a young age, Shaywitz said. Teachers need time to modify approaches to reading instruction for certain special-needs children.

That said, dyslexia sometimes goes unrecognized for good reason, Shaywitz said. Most children who suffer from the disorder eventually develop compensatory systems, shifting the burden of reading to other parts of the brain. This ability to adapt is reduced as children age beyond the developmental point where such corrections can be made, she added.

“What our data show is that even children who can read words accurately are doing so with a great deal of difficulty,” she said. “This imaging shows us the neurological basis for that difficulty. Teachers mean well—but up until recently, they didn’t have the means to identify these problems.”

According to the National Reading Panel (NRP), commissioned by Congress in 1997 to evaluate different approaches to reading instruction, there are five critical skills educators must emphasize for improved reading lessons: phonemic awareness, phonics, fluency, vocabulary development, and text comprehension.

Shaywitz, who was one of 14 members to serve on the NRP, also pointed out the need to funnel these skills into gradual, progressive learning experiences.

“You really have to teach reading systematically and progressively,” she said. “Kids really do need a lot of practice to build these ‘neuro-replicas’ in the brain.”

But the exception with dyslexic students is that many of them need to spend a great deal more time developing basic skills and identifying the sounds associated with words, Shaywitz said. If students pass lessons and skill sets by compensating for certain inherent neurological defects, they eventually will reach a level where it becomes impossible to keep up with kids who read more easily. If uncorrected, the problems will persist and plague them for life, she said.

“We need to get to them in the first three grades. Learning to read can become such a burden as children age,” Shaywitz said.

If America really does plan to have all its children reading by third grade, as the Reading First initiative states, educators must be conscious of these difficulties when teaching to dyslexic students, Shaywitz said. Just because a student is dyslexic doesn’t mean he or she is incapable of learning. What it does mean is that the student needs to work harder to develop certain skills, she said.

At beginning levels it becomes extremely vital to stress phonemic awareness and the proper sounds associated with certain words, she said. Teachers also must strive to demonstrate what she called “systematic phonics,” where sounds are associated with lettered symbols.

Another important exercise is reading aloud, Shaywitz said. Children who suffer from reading disorders such as dyslexia benefit from the practice, because it lets the educator point out mistakes while guiding students to the proper corrections.

As it becomes increasingly obvious that more and more students require supplemental practice and individual attention to reach their full educational potential, some educators say the integration of new technology tools to individualize instruction and assess progress becomes essential.

“This issue brings to light the extreme need to increase the use of technology-based instructional strategies to support and augment what classroom teachers are able to accomplish with their students. In addition, educational technology allows the use of different learning modalities and the individualization of the curriculum, as well as therapeutic applications to help students with learning problems,” said Marc Liebman, superintendent of California’s Marysville Joint Unified School District.

Although the brain-imaging technology that enabled researchers to make their discovery—called functional magnetic resonance imaging (fMRI)—is painless and highly efficient as a research tool, Shaywitz said she does not yet envision a time when brain scans will be used to diagnose dyslexia on a clinical basis, nor does she see a need for such a step.

“You don’t necessarily need a high-tech solution to [diagnose dyslexia],” she said.

Dyslexia is not hard for doctors to diagnose clinically, and fMRIs cost a great deal more time and money than the alternative, Shaywitz said. Still, the technology is critical on the research level, because it provides a guide to clinical work and an explanation for those educators who for years have misunderstood the affliction, she said.


Yale University School of Medicine, Department of Pediatrics

No Child Left Behind

National Reading Panel

Marysville Joint Unified School District

eSchool News Staff

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