Findings
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% to 14% 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.
In a 2005 study, Panagiatos Simos, PhD, of the University of Texas Health Science Center at Houston, and colleagues used technology called magnetic source imaging (MSI) to compare brain activity patterns of kindergartners with either good or poor prereading skills. Then they followed the children into first grade. The images showed that children who became skilled readers by the end of first grade had, as early as kindergarten, effective brain activation patterns for reading. Children who had a bumpier start with reading skills showed different patterns. However, 13 of the 16 children with reading difficulties responded to systematic reading instruction. After a year of direct instruction in the “alphabetic principle” (how letters work together to make words), comprehension (the meaning of words), and fluency (accurately reading words aloud), the students with previous reading difficulties became average readers. What’s more, the MSI images showed that during the course of first grade, the children’s brains started to bring critical reading areas—areas they hadn’t used before—into the reading process.
More recently, scientists have found that brain activity isn’t the only thing that differs between children who read well and those who experience reading difficulties. For example, Guinevere Eden, PhD, at Georgetown University, and colleagues found that children with dyslexia don’t just have different levels of activity within certain brain regions; they also show poorer connectivity between brain regions. And that connectivity can improve following targeted reading instruction, they found. Researchers at the University of Washington, meanwhile, have used brain imaging to show that children with dyslexia show an increase in their brain’s gray matter—the bodies of brain cells—after intensive reading training. The increase in gray matter volume corresponded with reading improvements.
Other studies have identified brain differences among children who respond to reading intervention and those who don’t. In 2007, for example, Simos’ team used MSI to look at brain activation in 15 first-graders with severe reading disabilities who hadn’t made progress despite quality reading instruction. The children received intensive instruction that focused on skills such as phonological decoding (figuring out how to pronounce a word) and rapid word recognition. Eight of the children showed significant improvement in reading ability, and MSI results confirmed that their brains had begun to function more like those of “normal” readers. The seven children who did not improve in reading ability also failed to show the “normalizing” changes in their brains. Such findings may lead to more targeted interventions for specific reading disorders.
Research also suggests that improvements from reading instruction persist. A 2008 study found that compared to good readers, poor fifth-grade readers had lower activity in a region of the brain called the parietal cortex. After intensive instruction, the poor readers showed increased activity in portions of that region. One year after the intervention, that activity had continued to increase, resulting in normal levels of brain activation.
