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Brain scans can detect dyslexia, showing root
of reading problem
By Robert Lee Hotz, Los
Angeles Times, August 3, 2002
For those
who struggle with dyslexia, a reading problem that confounds one in
five Americans, the written word is a misfire in the mind.
Indeed, a lifetime of reading problems can be traced to a distinctive
flaw in the brain that makes the mind strain and stumble over written
words. That telltale signature of dyslexia now can be detected
reliably in brain scans of children as young as 7, researchers
discovered.
In the largest brain-imaging study so far of children with reading
problems, Yale University researchers determined that the act of
reading prompted different patterns of mental effort in children with
dyslexia, compared with those who read more easily.
Their work is the latest study to reveal that reading challenges the
brain in subtle and disconcerting ways, all involving a complex
network of neural circuits called into action every time the mind
encounters a word on the page.
The scans showed that people with dyslexia have a much lower level of
activity in areas at the back of the brain thought to be responsible
for quickly matching words, sounds and meaning, compared with normal
readers.
Moreover, the pattern of activity in neural circuits that handle the
written word was the same as previously detected in adults with
dyslexia, who have wrestled with the written word for a lifetime.
``We know now that this disruption is not due simply to a lifetime of
poor reading because we see it in children as young as age 7,'' said
Dr. Sally Shaywitz, director of the Yale University Center for
Learning and Attention and a co-author of the study published July 15
in the research journal Biological Psychiatry.
``The disruption is right there from the time they are beginning to
read,'' she said.
The results are noteworthy, several reading experts said, because they
encompass so many children.
``This is the first study, not just in dyslexia but in any cognitive
aspect of the brain, that has used a sample so large,'' said Guinevere
Eden, director of the Georgetown University Center for the Study of
Learning in Washington, D.C.
University of Southern California psychologist Franklin Manis, who is
leading a five-year, $1.8 million study of reading problems and the
brain involving several hundred children, called the findings
``striking.'' They offer confirmation of evidence that reading
disorders such as dyslexia, which affect as many as 8 million children
ages 4 to 13, are caused by subtle problems in brain cells and
synapses, not by any lack of intellectual ability or motivation.
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