Study of dyslexic brain finds three word forms responsible for reading success
To normalize brain, children must grasp relationships among spoken, visual, and meaning forms and their parts
SEATTLE, WA--Researchers at the AAAS (Triple-A-S) Annual Meeting reveal new findings on effective therapeutic approaches for dyslexia, confirming that the brains of individuals with the reading disorder can be made to read normally; the instructional therapy is informed by findings of genetic research. AAAS is the American Association for the Advancement of Science.
"We found that specialized teaching gave the dyslexics' brains a 'jump start' that resulted in activation of the same brain areas used by normal readers" said Elizabeth Aylward, Professor of Radiology at the University of Washington.
Using MRI technology, Aylward and her colleague Virginia Berninger, Professor of Educational Psychology at the University of Washington followed the impact on the dyslexic brain of a unique teaching method, applied over three weeks, which focused on the interrelationships of the sound form, the visual form, and meaning word form and their parts. The meaning word form has parts that signal meaning and grammar. Results showed that training the meaning word form improved ability to analyze sounds and training sounds improved ability to analyze meaning word forms in specific regions of the brain. Whether and how the brain changes depends on the nature of instruction children receive.
"Many educators debate whether it's more effective to teach reading using phonics, which is sound-based, or emphasizing meaning," Berninger said. "But we found that the brain's neural computations are sensitive to sound-meaning interrelationships. Despite differences in the brains of dyslexics and good readers at the beginning of the study, dyslexics could learn if instruction explicitly made them aware of the word forms, their parts, and their interrelationships
Aylward, a professor of radiology at the University of Washington, said that before-and-after images of the brain regions needed for reading indicated that regions that had been relatively inactive in dyslexic children began to respond like those of normal readers after this special instruction--probably because they improved in linking the sound and meaning word forms.
"This research has scientific significance for understanding nature-nurture interactions" Aylward said. "Genes and neurons constrain learning, but instruction may exert specific effects on specific brain functions in specific brain regions. This research also has educational significance for preventing and treating reading disabilities. Language has multiple components, each of which has a different biological basis and must be orchestrated in very specific ways in instructional interventions for students who are at-risk biologically for dyslexia."
In the UW Multidisciplinary Learning Disabilities Center, researchers are studying multigenerational families that each has at least one dyslexic child. Applying sophisticated and powerful new methods to model the inheritance patterns and map genomic locations of genes involved in dyslexia, the researchers are drawing on genetic material gathered from 111 families with a total of 898 members.
"A variety of molecular genetic approaches have been taken to locate genes for component language processes that contribute to dyslexia," notes Wendy H. Raskind, Professor of Medicine/Medical Genetics and Psychiatry and Behavioral Sciences. "We are beginning to study our genome-wide marker scan in detail to identify more locations where putative genes for dyslexia may reside. What is exciting is that the behavioral measures (of sound, visual, and meaning word forms) used as clues to find those gene locations are yielding instructional clues for effective treatment."
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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