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.
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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.)
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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.
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.)
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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:
"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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