New research by Carnegie Mellon Psychology Professor Marcel Just investigates the cause of dyslexia — and it's not a visual scrambling of letters and words, as has long been believed.
Using functional magnetic resonance imaging (fMRI), Just and research fellows Ann Meyler and Tim Keller measured blood flow to different parts of the brain in real time. They now know that the reading disability involves underactivation in the part of the brain that decodes the sounds of written language.
As a normal reader sounds out words, this area of the brain (just above the left ear) lights up brightly on brain scans. The same area appears much less active in poor readers.
"With the right kind of intensive instruction, the brain can begin to rewire itself and overcome reading deficits, even if it can't eliminate them," said Just.
His view is based on Carnegie Mellon research that involved scanning the brains of kids who had received a year of concentrated reading instruction.
"[The children] showed 40 percent more activity in the word-decoding area of their brains after receiving the instruction," explained Just. "But while the results are hopeful, it's important not to be overly optimistic."
While dyslexic children and adults can often improve their accuracy and understanding of individual words after intensive instruction, it is rare that they can ever read as quickly as the average reader.
"All education is a matter of training of the brain. Learning to read is just one case where a particular brain area sometimes is not performing as well as it might, and remedial instruction helps to shape that area up," said Just.
Just says he would love to see a special school for children with reading disabilities in Pittsburgh.
"Reading is one of the few kinds of shared cultural expertise that we have," he said. "It's not as though we can all program computers or we can all play basketball, but almost everybody reads, so you're out of luck if you don't learn to do it."