Learning disabilities research encompasses education and biology

Although the causes are not fully understood, studies have shown a relationship between some learning disabilities and subtle abnormalities in parts of the brain that process language. Delving deeper into the biological underpinnings of learning disabilities, other studies point to genetics as accounting for 30 to 40 percent of the factors contributing to learning disabilities. The bulk of the contributing factors are thought to be environmental.

A multi-faceted effort, led by two CHDD research affiliates, seeks to gain a better understanding of both the biological and educational aspects of learning disabilities, and the links between them. Drs. Virginia Berninger, professor of educational psychology, and Wendy Raskind, associate professor of medicine, are co-principal investigators of the UW Learning Disabilities Center. The Center is funded by a five-year grant from the National Institute of Child Health and Human Development (NICHD). One of five such centers in the nation, the UW Center is the first to involve a major collaboration between medicine and education, explains Berninger.

"We're tapping into each other's expertise," says Raskind, an internist and geneticist. "As a physician, I can make a diagnosis of a hematological disorder, but I can't diagnose a learning disability."

"Our approach is important because learning disabilities are both educational and biological problems," says Berninger, an expert in assessing and teaching children with learning disabilities who has conducted learning disabilities research for the past 10 years. "Investigating the biological aspects helps us understand why some children have an inordinate struggle in learning to read and write despite adequate intelligence and instruction. Research on the educational aspects sheds light on specific instructional strategies that are effective in teaching children with learning disabilities to read and write. One of our main goals is to disseminate our results to help children, teachers and families better deal with learning disabilities."

The Center includes three major research projects and several smaller-scale projects involving children, teachers and families in the Seattle area. Three cores and a scientific advisory board chaired by CHDD research affiliate Dr. Alan Unis, associate professor of psychiatry and behavioral sciences, provide administrative and technical support for the research projects. One core is responsible for testing study participants for specific learning disabilities--dyslexia, which is defined as a discrepancy between verbal IQ and achievement in word recognition, and dysgraphia, a discrepancy between verbal IQ and achievement in handwriting, spelling or composition.

Two of the Center's major projects are exploring different educational aspects of learning disabilities. In one project, Berninger, Dr. Robert Abbott, professor of education, and their colleagues are evaluating the effectiveness of alternative educational interventions for treating reading disabilities. This project parallels a separate NICHD-funded effort headed by Berninger that is investigating treatments for writing disabilities. Together, Berninger's studies cover learning disabilities that affect either the processing or production of written language. Both projects include prevention, and short-term and long-term intervention studies with children in primary grades. The long-term treatment studies aim at demonstrating that individualized theory-based intervention can bring children with severe reading or writing disabilities up to grade level. The prevention and short-term studies are designed to test the idea that teaching combinations of connections between units of print and sound is more effective than teaching single connections.

"When you spell, you go from a sound representation to a written representation. You can make this translation at different units of sound and print, for example, a phoneme will translate to one or two letters, a syllable to a small group of letters, and a name code to a word-specific representation or sequence of letters. Our hypothesis is that it isn't just one of these units of translation that is used in learning to spell, but rather a combination of them or multiple units," explains Berninger. The same concept applies to word recognition in reading, except the translation process is reversed, going from a written unit to a sound unit. Individuals with learning disabilities have trouble with some part of the translation process.

"Our research will be comparing the conventional approach of teaching component reading and writing skills with alternative approaches informed by neurodevelopmental theory," Berninger points out. "We will be using state-of-the-art statistics to analyze the effectiveness of the various interventions, including growth-curve analysis that measures change over time, rather than just pre-intervention and post-intervention."

Another major project seeks to apply the results of research that demonstrate effective methods for teaching children with learning disabilities. Led by Dr. Deborah McCutchen, professor of education, and Dr. Susan Nolen, associate professor of education, the project conducts summer training institutes for primary grade teachers. Training focuses on giving teachers a variety of instructional strategies for teaching component reading and writing skills. The project will follow participating teachers as they implement the strategies they have learned.

Biology is the focus of the Center's third major project--an investigation of genetic contributions to learning disabilities. "There is no argument that there is a genetic component to learning disabilities," says Raskind, who heads the project. Studies have shown that learning disabilities cluster in families and have suggested that genes on three different chromosomes may play a role in learning disabilities. But, Raskind explains, many questions remain about how genes are involved, what function such genes might have and how much weight the genetic component carries in relation to environmental factors involved in learning disabilities.

To find answers, Raskind and her colleagues, Dr. Ellen Wijsman, research associate professor of medicine, and Dr. Li Hsu, staff scientist at the Fred Hutchinson Cancer Research Center, are investigating genetic factors in specific subtypes of learning disabilities and identifying genes that contribute to those learning disabilities.

"Learning disability isn't one defined condition, but a heterogeneous group of problems," explains Raskind. "Learning disabilities that affect reading and writing may be distinct disorders. Furthermore, each of these disorders has distinct and shared components and subcomponents that could represent the unctions of different genes. Alternatively, there might be a 'master' gene involved."

By constructing pedigrees of families whose members have specific learning disabilities, Raskind and her colleagues will be able to determine the pattern of inheritance, then work to pinpoint genetic mutations shared by individuals who have learning disabilities. Eventually they hope to identify the responsible gene or genes.

"Uncovering the gene or genes related to learning disabilities could help us identify children who are at increased risk for learning disabilities, which could enable them to begin intervention programs before they have trouble in school," notes Raskind. "It will also make it possible for us to learn what these genes actually do, what proteins they code for. Knowing the function of the genes may allow us to understand the problem at a more basic level and help in developing specific educational interventions that correspond to specific types of learning disabilities.

"Learning disabilities are not disorders that are likely to be amenable to genetic engineering," Raskind emphasizes. "If we can't modify the genes, we have to find out what we can do to modify the environment." In another project related to the biology of learning disabilities, Dr. Stephen Dager, associate professor of psychiatry and behavioral sciences, and Dr. Todd Richards, associate professor of radiology and CHDD research affiliate, are using an innovative functional imaging technique to study brain activity in children with learning disabilities. One goal of this project is to examine the link between biology and the environment by imaging brain activity before and after educational intervention.

The non-invasive imaging technology called Proton Echo Planar Spectroscopic Imaging (PEPSI) was developed by a group of investigators from the UW and the National Institutes of Health. It uses the same equipment as Magnetic Resonance Imaging (MRI), a diagnostic technique that gives a view inside the body and is commonly used to diagnose brain tumors and joint injuries. PEPSI is software that enables the MRI scanner to map the spatial distribution of certain chemicals within the brain.

With this technique, Dager and Richards can measure these chemicals as a person is thinking and generate images of chemical activity that correspond to mental activity. Creatine and phosphocreatine are chemicals known to be important in brain activation and learning. By mapping those chemicals in a region of the brain involved in language, they will compare brain activation in children with dyslexia or dysgraphia with brain activation in controls who do not have learning disabilities.

Mapping is done as study subjects are given language tasks specifically designed to test underlying problems in reading and writing. "In people with learning disabilities, we expect to find different patterns and intensity of brain activation," says Richards.

Those patterns may change as educational treatment improves reading and writing skills, explains Dager. "Along with learning more about why some children have learning disabilities, for the first time we may be able to show that learning has altered brain chemical activity," he says.

The UW Learning Disabilities Center takes parent, teacher and psychologist referrals for children with suspected learning disabilities in grades 1 through 6. For more information, call Dr. Mardean Francis at 206-543-1846.

Focusing on the physical sensations of making specific sounds is an effective way to teach children with learning disabilities the sounds associated with letters and letter combinations.

Top of Page | Next Story | CHDD Home