New advances in brain-imaging technology are helping scientists discover what happens in the brain when children read. By comparing the images of children who are known to have reading difficulties with those of children who are strong readers, researchers are learning more about how to help children overcome reading problems. Furthermore, images that show what happens to children’s brains before and after they get systematic, research-based reading instruction show that the right teaching methods can normalize brain function and thereby improve a child’s reading skills.

As many as one out of every five children has a significant reading disability, according to the National Center for Learning Disabilities. Reading disorders, which affect boys and girls equally, can cause difficulties in school and into adulthood. The most common reading disorder, dyslexia, affects an estimated 13 percent to 14 percent of the school-aged population, according to the International Dyslexia Association.

Many children with reading disorders have trouble with a process called “decoding” — essentially, figuring out the different sounds assigned to different letters, and correctly applying those letter-sound relationships to pronounce written words. In the first stage of scientific reading research, experts hypothesized that decoding difficulties were caused by a problem in the brain, and had more to do with sound than with sight. Brain-imaging studies confirmed that hypothesis, joining other psychological studies in establishing that dyslexia does not reflect visual problems or lower intelligence.

Now, psychologists are learning more about what happens in the brain during reading — and testing whether certain kinds of reading instruction can actually change the brain.

Sally Shaywitz, MD, and Bennett Shaywitz, MD, of Yale University, showed that when children without reading problems tried to distinguish between similar spoken syllables, speech areas in the left brain worked much harder than matching areas in the right brain. But when children with reading problems made the same attempt, those parts of the right brain worked harder, going into overdrive after a brief delay. In a 2004 study, the Shaywitzes found that when second- and third-grade students with dyslexia learned to read through an experimental eight-month intervention, those critical left-hemisphere areas became active, looking more like the brains of normal readers.