Dyslexia is a relatively common diagnosis among American children as about 5 to 10 percent of kids fit the description.
In the past, being dyslexic was a label assigned to kids who were bright, even verbally articulate, but who struggled with reading. Typically these kids scored high on IQ tests but had low reading scores.
For the kids who scored low on IQ tests and also displayed low reading skills, experts believed the reading troubles were merely a result of general intellectual limitations.
Now, a new brain-imaging study challenges this understanding of dyslexia.
“We found that children who are poor readers have the same brain difficulty in processing the sounds of language whether they have a high or low IQ,” said Massachusetts Institute of Technology neuroscientist John D. E. Gabrieli, Ph.D.
“Reading difficulty is independent of other cognitive abilities.”
This revelation could change the ways educators help all poor readers.
The findings of Gabriel and his colleagues will be published in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science.
The study involved 131 children, about 7 to 17 years old. According to a simple reading test and an IQ measure, each child was assigned to one of three groups—typical readers with typical IQs; poor readers with typical IQs; and poor readers with low IQs.
All were shown word pairs and asked whether they rhymed. Spellings didn’t indicate sound similarities. Using functional magnetic resonance imaging, or fMRI, the researchers observed activity in six brain regions important in connecting print and sound.
The experts found that poor readers in both IQ groups showed significantly less brain activity in the observed areas than typical readers.
However, there was no difference in the brains of the poor readers, regardless of their IQs.
“These findings suggest the specific reading problem is the same whether or not you have strong cognitive abilities across the board,” said Gabrieli.
Researchers believe the study has important implications for both the diagnosis and education of poor readers.
While educators commonly offer reading- and language-focused interventions to bright dyslexics — to bring their reading up to the level of their expected achievement — they may want to consider such remediation for less-“smart” children.
If teachers understand that the same thing is going on in the brains of all poor readers, they may see that all those children could benefit from the same interventions.
Since it’s hard to learn much if you can’t read, that’s good news for a lot of kids.