Dyslexia And The New Science Of Reading

This didn't help at all because most dyslexics see as well as anyone else. But they do have trouble pulling words apart into their constituent sounds, what scientists call phonemes. These are the smallest discernible segments of speech; there are more than 40 of them in the English language. To understand how this process works, Shaywitz uses the example of the word "cat," which is made up of three phonemes: "kuh," "aah" and "tuh." Most people understand this, but dyslexics can hear only "cat"--one sound. As a result, they can't sound out words, the first step in reading. Most people race through this sounding-out phase and the process becomes an automatic, essentially unconscious, part of reading. Dyslexics get stuck at the starting gate because they can't make the connection between the symbol and the sound.

Researchers are getting a clearer picture of why this is happening by using new imaging techniques. Brain scans are now showing that when dyslexics try to decipher words, certain areas in the back of the brain are underactivated, while other areas in the front are overactivated. In the September issue of the American Journal of Neuroradiology, Berninger and her colleague Todd Richards reported on a study in which they scanned the brains of six dyslexic and seven nondyslexic boys performing three different tasks: telling two musical tones apart, distinguishing real spoken words from nonsense and picking out rhyming syllables. The only difference was in the rhyming task. Dyslexics scored significantly lower and scans showed that regions in the front of their brains were in overdrive. This suggests that dyslexics have to work much harder to analyze sound patterns. The sounding-out process wasn't efficient.

Shaywitz and her husband, Bennett (co-directors of the NICHD-Yale Center for the Study of Learning and Attention), are using functional magnetic resonance imaging (fMRI) to track blood flow through the brain. The areas that receive the most blood are working the hardest. Last year they reported in the Proceedings of the National Academy of Sciences that they saw a similar pattern of increased activity in the front of the brain, an area that's known to govern speech production. "What we believe is that dyslexics are trying to find another way to get at the sound of the word," says Sally Shaywitz, perhaps by saying words under their breaths. This could be one cause of dyslexia: inefficient pathways in the brain.

Because of this research, scientists now have a much better understanding of how we process written language. What they're realizing is that learning to read is not a natural process like learning to speak. "Speech is a biologically hard-wired ability," says Reid Lyon, chief of the child development and behavior branch of the National Institute for Child Health and Human Development (NICHD). "Almost all humans acquire it in the same way. They coo, then they babble, use single words, then put two words together." Scientists estimate that the ability to use speech is at least 100,000 years old while written language is only about 5,000 years old. Because written language is so new, learning it is not in our genes; we have to be taught.

Which reading method works best? The answer is a lot more complicated than the much-ballyhooed "reading wars" of the last decade, in which proponents of whole language or phonics each claimed the true path to literacy. The often highly politicized debate distracts from the real issue, that both methods are failing too many kids. Instead, experts say, reading needs to be taught in a carefully sequenced way that includes pieces of both these methods, plus much more. It must be based on solid research and geared to the needs of individual kids. No single strategy will work for everyone who's having trouble, researchers say. "People can respond differently to a similar deficit," says Georgetown University neuroscientist Guinevere Eden. "Some can draw on other skills." The right method for a particular child depends on the severity of the problem and the age at which a youngster is diagnosed.

Everyone agrees that early intervention is the most effective. Researchers suspect there's a window between the ages of 5 and 7 when the underlying skills of reading are most easily learned. "If kids are at risk, we can address it with 30 minutes of intervention a day at the kindergarten level," says Lyon. "By the time the children are 8 or 9, it takes at least two hours a day of special training." The key is finding those at risk early. One new screening test, developed by Barbara Foorman and her colleagues at the University of Texas-Houston Medical School, asks kindergartners to give the sounds for specific letters and sets of letters. Kids who have trouble get more specific diagnostic testing. This fall, Foorman's two-minute test, called the Texas Primary Reading Inventory, will be used in 89 percent of the state's school districts. Marilyn Jager Adams, a researcher at the Harvard Graduate School of Education, has also developed a two-minute screen, currently being tested in Kansas schools. It checks kindergartners for basic skills and tests higher-level abilities, such as fluency and word recognition, as children progress.