July 21, 2003 -- Kids with dyslexia show different brain activity patterns than kids who read normally, but new research suggests these differences disappear after just a few weeks of reading instruction.
The encouraging findings offer some of the best evidence yet that even limited special training can dramatically affect a dyslexic child's ability to learn to read.
"Even though dyslexic children start out with some deficits in functional activity with regard to language, our message is that the brain can change," study co-author Todd L. Richards, PhD, tells WebMD. "New connections can form and these children can improve."
Richards and University of Washington, Seattle, colleagues used functional magnetic resonance imaging (fMRI) to measure brain activation patterns among 10 children with dyslexia and 11 children who were normal readers. Though the patterns were very different at the start of the study, they were almost identical after the dyslexic children received just 28 hours of comprehensive reading instruction. The findings are reported in the July issue of the journal Neurology.
A Common Learning Disability
Dyslexia is the most common learning disability in the United States, with prevalence estimates ranging from a low of 7% of the population to a high of 20%. Earlier research has shown that people with dyslexia have abnormal levels of activity in brain regions connected with language.
Dyslexia is marked by difficulty processing language sounds that can lead to consequences ranging from problems in reading comprehension to reduced reading and vocabulary skills.
This is the first published study to assess the impact of treatment -- in this case, special reading instruction -- on brain activity patterns among dyslexic children. Tests administered during fMRI scanning measured the children's ability to process language sounds, a task dyslexic children have difficulty with.
Another language skill, known as morphologic awareness, is known to be associated with reading disability and was found to be strongly associated with dyslexia. Morphologic awareness involves the understanding of how word parts contribute to their meaning. In the test, children were presented with two words and they had to decide if the first word contributed to the meaning of the second. The answer would be yes, for example, for the words "builder" and "build" and no for the words "corner" and "corn."
Brain Patterns Similar
Before the special reading instruction, the dyslexic children in the study showed less brain activation than normal in tests administered while performing morphologic awareness tasks. Brain patterns increased to normal levels, however, following the three weeks of intensive instruction.
In a news release, lead researcher Elizabeth Aylward, PhD, noted that the special instruction doesn't result in a "rewiring" of the brain, as some experts have suggested. Rather, it strengthens the normal brain circuits that are already in use.
"Our findings showed that morphologic processing is very important in helping children learn to read," Richards says in the release. "But that doesn't mean that phonological processing isn't important."
International Dyslexia Association Executive Director J. Thomas Viall says new research has forced people to rethink their notion of neurologic development and the treatment of reading disorders.
"What we are beginning to understand is that the brain is incredibly adaptive," he tells WebMD. "In the case of dyslexia, where the brain is not well structured to perform the task of reading, we are finding that the brain develops alternative pathways to make reading possible."
Viall says early diagnosis and instruction are critical for children with dyslexia.
"Seventy-five percent of kids who leave third grade reading below their grade level struggle with reading their whole lives," he says. "Reading is the key to educational success, and educational success is the key to economic success. A child who leaves school with poor reading skills is, in most cases, doomed to a life of unemployment and underemployment."