Even though there is evidence that dyslexia has a genetic basis, researchers will report new findings today (Feb. 12) that show children afflicted with the learning disability are not doomed to a life of reading difficulties.
The brains of dyslexic children can be "jump-started" with a three-week-long instructional intervention to help them use the same brain areas as normal readers, leading to better reading ability. This intervention was developed at the University of Washington by Virginia Berninger. She and Elizabeth Aylward, both of the UW's multidisciplinary Learning Disabilities Center, will discuss their findings at a press briefing during the annual meeting of the American Association for the Advancement of Science in Seattle. Also participating in the briefing will be Dr. Wendy Raskind, UW professor of medicine, who will talk about genetic influences on dyslexia.
"Most people think words are just words, but the human brain uses three neural circuits to code words in three forms, not just their meaning," said Berninger, a professor of educational psychology and director of the center.
She explained that the brain codes words by their sound (or phonology), by the parts of words (or morphology) that signal meaning and grammar, and by their visual or written form (or their orthography.) "The teaching that gave dyslexic brains the jump-start was unique in that it made every aspect of reading words explicit. It drew their attention to the sound form, the meaning form and the written form of words, and showed how to interrelate them," Berninger said. "While many educators debate whether phonics or meaning-based instruction is more effective, we found that an effective way to treat dyslexia is to show children explicitly how letters, sounds and meaning are interrelated."
The researchers used functional Magnetic Resonance Imaging (fMRI) to measure the impact of the intervention that emphasized these three word forms on brains of fourth through sixth grade dyslexic children.
Aylward, a UW professor of radiology, said that images of the brain regions required for reading showed areas that had been relatively inactive in dyslexics began to respond like those of normal readers following the intervention. In addition, dyslexic children's skills improved on standardized reading tests.
The researchers also unexpectedly found cross-language coding improvements. Some of the dyslexic children only received sound training, but the post-intervention imaging showed improved brain activation in areas associated with the meaning form as well as the sound form. Similarly, children given instruction in the meaning form exhibited increased brain activation in the sound form in addition to the meaning form. "Genes and neurons constrain learning, but instruction may exert effects on specific brain functions in specific brain regions," Aylward said. "Language has multiple components, each of which has a different biological basis and must be orchestrated in very precise ways in instructional interventions for students who are at-risk biologically for learning to read."
Raskin will outline the Learning Disabilities Center's effort to model the inheritance patterns and to map the location of genes involved in dyslexia. This multi-generational study of 111 families with at least one dyslexic child involves genetic material from 898 individuals.
"While we hope to identify more locations where reputed genes for dyslexia may reside, what is exciting is that the behavioral measures used as clues to find those gene locations are yielding instructional clues for effective treatment," Raskind said.
"All of this research indicates that just because there is a genetic basis to dyslexia, it doesn't mean dyslexics can't learn to read," said Berninger. They and their teachers have to work harder, but these children's brains can function normally with extra help."
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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