Learning Disabilities: Research Activities and Scientific Advances

More than 4 million school-age children in the United States have been diagnosed as having learning disabilities. These disabilities can take a significant toll on children and their families. The NICHD supports extensive research to understand and address reading, writing, and related disabilities and disorders.

Institute Activities and Advances

The NICHD has an extensive history of supporting research on learning disabilities and comorbid conditions. Much of the NICHD research in this area is supported by the Reading, Writing, and Related Learning Disabilities (RWRLD) program and the Mathematics and Science Cognition and Learning (MSCL) program, which are part of the Child Development and Behavior Branch (CDBB).

The RWRLD program focuses on research and training initiatives to increase understanding of normal and atypical development of reading and writing skills across the lifespan. It also focuses on developing prevention, remediation, and instructional methods to enhance reading and writing. The program portfolio includes multidisciplinary investigations that integrate genetic, neurobiological, cognitive/behavioral, and intervention studies as well as the development and validation of measurement tools to support these efforts. RWRLD efforts are complemented by other CDBB programs. These include the Early Learning and School Readiness Program; the Language, Bilingualism, and Biliteracy Program; and the Behavioral Pediatrics and Health Promotion Program.

MSCL focuses on basic and intervention research within all aspects of mathematical thinking and problem solving. It also funds research on scientific reasoning, learning, and discovery from infancy into early adulthood. It is especially interested in exploring a variety of influences on atypical development in mathematics and science learning and cognition in both humans and animal models, including genetic and neurobiological substrates, and cognitive, linguistic, sociocultural, and instructional factors. Core areas of research focus include investigations of the individual differences that may moderate achievement in math and science; the delineation of skill sets needed to attain proficiency in these domains; the means to address the kinds of learning difficulties that frequently emerge in each of these areas; and the development of effective instructional methods for mitigating these difficulties.

In 1997, the NICHD and the U.S. Department of Education responded to a congressional request by creating the National Reading Panel to review scientific evidence on reading and identify the most effective ways to teach children to read. The Panel’s report, which included research supported by the RWRLD program, noted that children who received explicit instruction in specific components of reading were more successful readers than those who did not receive such instruction. The Panel’s findings have since contributed to nationwide standards in education.

NICHD-sponsored research also influenced the 2004 revision of the IDEA legislation. The research demonstrated the limitations of identifying reading disabilities based solely on discrepancies between a child’s IQ and achievement, called the discrepancy model. Now states can consider alternative approaches to identifying learning disabilities, and educators can provide early intervention. In a related study, NICHD-sponsored researchers recently used brain imaging technology to compare the brain functioning of poor readers with low IQ scores and poor readers with typical IQ scores. They found no reliable functional brain differences between the two groups, thereby strengthening the evidence against the discrepancy model.

Improvements in brain imaging technology have helped advance understanding of learning disabilities in many ways. For example, NICHD-supported researchers used brain imaging tests to show that the functional brain metabolism of poor readers changes with successful reading remediation to more closely resemble that of skilled readers.

To better identify individuals at risk for learning disabilities and create appropriate interventions, researchers need to understand how relevant genes interact with each other and with the environment. NICHD-supported researchers located a dyslexia-susceptibility gene and contributed to the establishment of many links between specific chromosomal sites and reading ability; dyslexia is not a single gene disorder, and researchers are continuing to research this complex issue. In addition, using longitudinal studies of twin cohorts, NICHD-supported researchers demonstrated that genes’ effects on reading performance are modulated critically by the child’s environment.

NICHD-funded researchers are also working to improve understanding of dyscalculia. One recent study identified several factors underlying the disorder, including difficulty comprehending that any number or quantity can be broken into smaller numbers. The study also found that children considered low achievers who do not have dyscalculia struggle less than children with the disorder. In part, this is because the youngsters without dyscalculia are better able to memorize new math facts. A separate study found that less sensitive innate ability to estimate and compare quantities without counting may underlie dyscalculia. In children without dyscalculia but with low math achievement scores, this innate ability appeared similar to that of their typically achieving peers. These results suggest that children with dyscalculia may have distinctly different deficits and need interventions designed to target these unique challenges.

Other Activities and Advances

The NICHD continues to create, collaborate in, and support various activities to advance the field. These efforts include the following:

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