DYSLEXIA FINDING OFFERS HOPE
Kansas City Star, Associated Press, Friday, February 16, 2001
SAN FRANCISCO – Discovery of a deficit in key reading and visual centers of the brain could lead to early diagnosis and treatment for dyslexia, a disorder that affects about 15 percent of the population, researchers report.
A study at Georgetown University Medical Center in Washington suggests that people with dyslexia have a much lower level of activity in the brain’s left inferior parietal, an area that is important in reading and in processing visual images.
Guinevere Eden and Thomas Zeffiro, a husband and wife team and co-directors of the Center for the Study of Learning at Georgetown, also found that the right inferior parietal can be taught to compensate for the weakness in the left side of the brain through a program of intense reading training.
“These study results are further evidence that dyslexia has biological roots,” Eden said.
It is estimated that 5 percent to 15 percent of the population suffers from some degree of dyslexia, she said. Some learn to compensate and eventually become good readers, but Eden said many adults cannot read because the problem was not identified and treated in their school years.
DEALING WITH DYSLEXIA, LANGUAGE IS A FACTOR
Kansas City Star, Associated Press, Friday, March 16, 2001, p. A4
WASHINGTON – When English-speaking children with dyslexia begin to read, they face the awesome task of learning more than 1,100 ways that letters in the written language are used to symbolize the 40 sounds in the spoken language.
This may explain why there are twice as many identified dyslexics in English-speaking cultures as in countries with less complex languages, according to a study appearing today in the journal Science. The study by an international team compared the brain scan images and reading skills of dyslexic university students in Italy, France, and England. The researchers found almost no difference in the neurological signature for dyslexia, but there was an immense difference in how well the students learned to read their native languages.
“It is much easier for dyslexics to learn to read in languages where there is a one-to-one relationship between letters and the sounds,” said Chris D. Frith, a researcher at the University College London and a co-author of the study.
In Italian, dyslexic students have a far easier time. The 33 sounds in Italian are spelled with only 25 letters or letter combinations. There are 32 sounds in the French language, which linguists say are written in about 250 difference letter combinations. The researchers noted that identified dyslexics are rare in Italy because the language helps learning readers to quickly overcome problems caused by the disorder. To find dyslexics among Italian university students, the researcher had to conduct special tests to identify those with the neurological signature for the disorder.
Dyslexia involves a brain structure that makes it difficult for a learning reader to connect verbal sounds with the letters or symbols that “spell” that sound. Such connections are essential to learn to read.
Thomas Zeffiro, co-director of the Center for the Study of Learning at Georgetown University, said the study by the European researchers was “an exciting result” for researchers studying dyslexia. But Zeffiro said the study, with only 72 subjects in three countries, was too small to draw final conclusions about how common dyslexia is among the peoples of the world.
SCANS SHOW CLUES TO ADHD
Kansas City Star, Associated Press, Friday, December 17, 1999
LONDON – For the first time, brain scans have revealed measurable biochemical differences in people with attention deficit hyperactivity disorder. The discovery could reduce the number of children mistakenly diagnosed and put on drug treatment, researchers say.
The diagnosis of the disorder, usually made in school-age children, is commonly based on observed behavior, and some experts think it is highly subjective – essentially just an educated judgement. Earlier studies have shown that scans can detect structural differences in disorder sufferers’ brains, as well as abnormalities in brain activity. Scientists suspect that defects in genes relating to the brain chemical dopamine probably are involved.
The latest study, conducted at Massachusetts General Hospital in Boston and published in this week’s issue of The Lancet medical journal, is the first to show a measurable biochemical abnormality in people with the disorder. The method “is the most promising development I’ve seen in a long time in terms of our coming up with an actual physical test that could help us pin down the diagnosis of ADHD,” said Edward Hallowell, a Boston psychiatrist and an expert in the disorder who was not connected with the research.
The disorder sufferers had 70 percent more dopamine transporters than their healthy counterparts. The scientists could not tell, however, whether that was a cause or an effect of the disorder. The increased number could either mean not enough dopamine is floating around the system or that too much is being produced, said one of the researchers, Bertha Madras, a professor of psychobiology at Harvard Medical School. “It’s very early days, but if all hyperactive adults and children show a 70 percent increase above normal in this test, I think it would de facto be considered a diagnostic,” Madras said.
Sam Tucker, a London-based pediatrician who specializes in the disorder, said that while the test could be useful, its potential as a definitive diagnostic test is uncertain. “Scanning is the way to go, but this along is not going to be the whole answer,” he said.