MONDAY, Aug. 23, 2004 (HealthDayNews) -- Brain images of people with a family history of dyslexia show significant reduction of gray matter in centers associated with language processing, Italian researchers report.
The finding, published in the Aug. 24 issue of the journal Neurology, lends credence to earlier studies that suggested intensive reading therapy activates parts of the brain needed for decoding words.
The new research "adds further support to the effectiveness of intensive reading remediation therapy to correct the reading problems associated with dyslexia," said Dr. Daniela Perani, head of research at the Institute of Neuroscience and Bioimaging in Milan and lead author of the report.
Dyslexia is a disability, usually occurring in males, in which people have trouble processing language-based information, making it difficult to learn to read, write, and spell.
Previous studies have found similar reductions in gray matter in language-associated brain centers. But the Italian research adds valuable information, said Guinevere Eden, director of the Center for the Study of Learning at Georgetown University.
"The findings are clearer in this case because the individuals came from the same family," Eden said. "When you look at people's brains, there is always some variability. The fact that these were brains of people from the same family reduced the variability."
The research included 10 people with familial dyslexia and 11 control subjects.
Another important aspect of the Italian study is that it links a number of brain centers associated with language, said Mark A. Eckert, a senior research scientist in the division of child and adolescent psychiatry at Stanford University.
The gray matter deficits in the Italian study were located in many brain areas -- top and bottom, front and back -- that are important for language functions, the researchers said.
"One problem of previous structural imaging studies is that they looked at only one brain structure at a time," Eckert said. "This [new study] shows that areas involved in both written and oral language are linked together, so you are probably talking about a network."
Eden also said earlier brain imaging studies clearly established "that there is a biological basis for dyslexia." And the finding of specific deficits in language-associated parts of the brain has led to effective therapy for dyslexia.
That therapy consists of intensive reading training sessions done day after day, with the objective of strengthening language-processing brain centers, in the same way that physical training is designed to strengthen muscles, Eckert and Eden said.
"Interventional studies have shown that the brain centers become activated after therapy," Eckert said.
An effort to develop more effective therapy is ongoing, he said, based, in part, on brain imaging. "In general, if we understand where some of the potential deficits in the brain are, we can target them," Eckert said.
More information
Learn more about dyslexia from the National Institute of Neurological Disorders and Stroke.
