HEALTH & FITNESS
Four years ago, two scientists announced that they had found a way to repair a fundamental defect in the brains of children and adults who fail to learn to read. They published articles in leading scientific journals, raised venture capital and formed a company to make their technique available to children, parents, teachers and schools across the nation.
Billed as an entirely new way to treat dyslexia, the technique uses repeated and fast-paced computer-generated exercises meant to make nerve cells work faster. After several weeks, circuits in the brain are reorganized in ways that are supposed to make it easier to learn to read.
Neuroscientists have long promised cures for brain and spinal disorders that afflict millions of people: stroke, spinal cord damage, Alzheimer's disease. If it works, its promoters say, the new dyslexia therapy will be one of the first to make good on that promise.
So does it work? Today, nearly 20,000 children and several hundred adults have gone through the intensive therapy, called Fast ForWord, and one would think a verdict would be available.
But the therapy has yet to be evaluated by independent scientists. Virtually all the research on how well it works has been carried out by Scientific Learning Inc. of Berkeley, Calif., the company that the two scientists founded to market it.
Independent evaluations of several intervention programs, including Fast ForWord, are now under way, but most results are several years off. Dr. Reid Lyon, who is in charge of studies sponsored by the National Institute of Child Health and Human Development in Bethesda, Md., says this is a common pattern with highly trumpeted educational innovations: every technique being marketed to schools and parents is said to be highly effective mainly by people who stand to make money on it, and independent assessments can lag years behind.
And this is only part of the problem for the program's proponents. Within the world of neuroscience, there is a fierce debate over the nature of how language is encoded in the brain, how it develops and what accounts for the fact the one in four children has problems learning to read. Given this lack of consensus, many educators and parents shy away from new therapies that are caught up in bitter infighting among scientists.
Meanwhile, Scientific Learning, the company that pioneered the new technique, is struggling to win acceptance in a very competitive market. It offered stock for public sale in July after losing $10.7 million on sales of $5.1 million in 1998.
The central idea behind the new therapy stems from a collaboration between Scientific Learning's two principal founders, scientists who pioneered research in previously unrelated fields.
One, Dr. Paula Tallal, a neuroscientist at the Newark campus of Rutgers University, is an expert in phonological processing -- how the sounds of language are encoded into the brain. The other, Dr. Mike Merzenich, a neuroscientist at the University of California Medical School at San Francisco, is a leading authority on brain plasticity, the ease with which the brain can reorganize and shape its circuits in response to learning.
English has 26 letters and 44 sounds, or phonemes. All words are made up of phonemes like ba and da or mu and nu. To learn to read, a child must be able to sound out phonemes and build them into words.
But here's the rub. The brains of some children, right from birth, cannot clearly hear phonemes that make rapid sound shifts. For example, the sound ''ba'' starts with a ''b'' made by pressing the lips together, and flows into ''aaaah'' made further back in the mouth.
The time between the ''b'' and ''aaaah'' is just 40 milliseconds (a millisecond is one-thousandth of a second), but most babies can hear it just fine, Dr. Tallal said. Some, however, need five times that long -- 200 milliseconds or more -- to really hear such sounds. Other phonemes, like mu, make slow sound shifts and do not create a problem.
Even the rapid phonemes do not prevent the babies with impairments from learning to speak and understand; they compensate by watching lips, learning words in context and other techniques invented on the fly. Most do fine, until it is time to read.
Here is where Dr. Merzenich's work in brain plasticity comes in. Babies' brains are highly plastic, he says. But once a brain circuit is laid down, subsequent repetitions tend to reinforce it.
In hearing about Dr. Tallal's work, Dr. Merzenich realized that many children who cannot learn to read have inscribed brain circuits that are constantly compensating for what they cannot hear clearly. They get ''good'' at being ''bad'' at language. Such children will not be able to sound out words until they learn to distinguish ''ba'' from ''da'' and all other phonemes.
Thus came the patented invention of processed speech, a key innovation at Scientific Learning. (It holds the patent jointly with Rutgers and the San Francisco medical school.)
The human voice cannot stretch the time between ''b'' and ''aaaah'' so that children with timing problems can hear it. But a computer can.
By stretching fast phonemes so that children can hear the difference between ''ba'' and ''da'' for the first time, the scientists laid the basis for changing their brains.
In colorful computer games and exercises with hundreds of variables and tens of thousands of repetitions, children gradually force their brains to hear these blurry phonemes faster and faster. In the training, children sit at a computer for 100 minutes a day, five days a week, for six to eight weeks. Scientific Learning charges a fee of $850 per child; schools or parents must also hire a professional to administer the program.
Good attendance is mandatory. At the end of each day, the computer evaluates each child's progress and establishes the next day's lesson plans based on progress made the day before.
The games work on more than timing, said Dr. Steve Miller, a neuroscientist who also helped found the company. They are designed to help children remember what they hear, to be aware that sounds are parts of words, to follow commands, pay attention and express ideas in a story line.
Dr. Tallal compared the approach to ''full-body aerobics versus training one muscle group at a time.'' But she added, ''It's not a cure for dyslexia.'' The training repairs a brain defect by altering brain organization, she said; this does not translate into an immediate ability to read, but it lays the foundation for learning how to read.
This is a claim under close scrutiny by scientists outside the company. For example, Dr. Guinevere Eden, a neuroscientist at Georgetown University in Washington, and colleagues at George Mason University in Fairfax, Va., are imaging the brains of children before and after Fast ForWord training. The study has not been published, but Dr. Eden said she could discuss general findings.
The children's brains do get faster at the types of exercises given by the computer, she said. But there is no evidence yet that this translates into an enhanced ability to learn to read. ''This is what parents want to know,'' Dr. Eden said, ''and we don't have the answer.''
Many conventional reading intervention programs are extremely good and can produce excellent results, said Dr. Lyon, of the National Institute of Child Health. They tend to work with children in one-on-one settings and use a variety of approaches to stimulate the brain and the senses of sight, hearing and touch.
Nevertheless, he said, Fast ForWord is an entirely novel approach. And many speech pathologists, teachers, educators and children give it glowing reviews. ''My kids have been through many intervention programs but none gave them as many gains as Fast ForWord,'' said Donise Pearson, president-elect of the Texas chapter of the Speech and Hearing Association, an organization of professional speech therapists. ''Parents report almost unbelievable changes in their children's behavior.''
Rita Gardner, principal of Shields Elementary School in Chicago, said: ''I'm a real believer. Many kids are in la-la land. You talk to them and they don't follow what you say. You give them lots of interventions and there are still holes in their learning. With Fast ForWord, it's like a light went on.''
Despite such comments, the new therapy has not been endorsed by many speech and language researchers.
''The training may have effects on some children, but not for the reasons
they suppose,'' said Dr. Michael Studdert-Kennedy, past president of the
Haskins Laboratories, a center for the study of speech and language at
''There's absolutely no evidence that there's a timing disorder'' in the brains of children who are slow to read, he said, adding that the failure to read is related to defects in parts of the brain that are specialized for language and have little to do with awareness of sound.
As for Dr. Merzenich's claim that the Fast ForWord technique is rapidly reshaping the plasticity of the brain, ''that's an absurd stunt'' that will not help anyone learn to read, Dr. Studdert-Kennedy said, adding: ''Obviously, there are changes in the brain after intense training. Everything you do changes the brain.''
Meanwhile, parents and teachers looking for dispassionate advice on whom to believe can turn to a nonprofit group, All Kinds of Minds, based in Chapel Hill, N.C., founded by a pediatrician at the University of North Carolina, Dr. Mel Levine. The organization disseminates scientific knowledge about learning disorders.
''There will never be one intervention for all kids,'' Dr. Levine said. ''In medicine, we've never found one antibiotic that works for all infections. Researchers need to be aware of which subgroups of children they can help. The physician in me knows that things can break in many places.''
''Maybe Fast ForWord found one such place,'' he added. ''That alone is important.''