Stump the Scientist Scenes from AAAS Science After Hours
February 16, 2001

The Search to Understand Dyslexia
by Judith Brand

Developmental dyslexia, a reading disorder affecting from 5 percent to 15 percent of the population, can cast intelligent children into the category of "poor readers." Yet with alternative methods of instruction, dyslexic children can become competent readers and successful students.

In order to effectively treat dyslexic children--that is, to design optimal educational interventions--scientists are attempting to understand the neurobiological foundations of the disorder. In the AAAS symposium "Brain Mechanisms of Reading and Dyslexia," researchers discussed what's known about dyslexia and the tools they're using to get additional information.

Perhaps the most promising technique for studying dyslexia is functional magnetic resonance imaging (fMRI). This is a noninvasive procedure that lets the researcher see the brain in action. Interestingly, dyslexics and nondyslexics often use different areas of their brains to deal with the same reading task. "Before" and "after" fMRIs of children who participate in reading intervention programs can reveal physiological changes that
underlie improvements in the children's reading behavior. This knowledge should lead to a better understanding of the causes of dyslexia, and will help scientists and educators design more effective interventions.

fMRI Brains These functional magnetic resonance imaging (fMRI) images show the brain of a nondyslexic person (left) and a dyslexic person (right). The colored areas show the parts of the brains that are active, or functioning, during the performance of a specific task. Although both individuals are performing the same task, different regions of their brains are active. This type of information can be used to design better educational intervention techniques for people with dyslexia. (Images courtesy of Guinevere Eden.)

Tips for Parents
After the symposium, I asked two of the scientists what message they might have for parents of young children. Dr. Frank Wood, of Wake Forest University School of Medicine-- Bowman Gray, said that early intervention can be extremely beneficial. Unfortunately, children often aren't evaluated until it's apparent that they have a serious reading problem. In Dr. Wood's opinion, it would be ideal to screen all children, except those already reading fluently, by about January of the first grade. If a child seems to have problems learning to read by that time, parents might want to talk with the child's teacher and possibly seek an evaluation for dyslexia through the school.

Dr. Guinevere Eden
Researcher Guinevere Eden from the Laboratory of Brain Function and Behavior at Georgetown University Medical Center in Washington, D.C. (Photo courtesy of Guinevere Eden.)

Dr. Guinevere Eden, from Georgetown University Medical Center, noted that dyslexic children have problems segmenting and manipulating the sounds that make up words--skills that are necessary for reading proficiently. Strengthening these skills will make any preschooler, dyslexic or not, more "reading ready." Here are some games Dr. Eden suggests parents might play with their kids to improve these skills:

  • Rhyming: "What rhymes with 'cat'?" "Cat, bat, dog, mat--which is the odd word out?" (dog)

  • Taking words apart: "Cowboy--take off the first part and what's left?" (boy) After children can segment two-syllable words, have them segment the sounds of a one-syllable word: "Take the first sound away from 'cow' and what's left?" (ow)

  • Sounding out: Sound out the parts of a word and ask the child to identify the word: "b-a-t--what's the word?" (bat)

    What About Those "b"s and "d"s?

"I've always heard that dyslexia is characterized by the reversal of letters: 'b' for 'd,' and so on," an audience member asked. "What's the story?"

The answer may be both surprising and reassuring. According to Dr. Eden, reversing letters is often just a sign that a child is a beginning reader.

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