Researchers in the lab and in the classroom have learned much about learning disabilities in the past decade: Early intervention works. The brain can adapt and change throughout childhood. Helping children overcome a problem is more important than defining the problem.
The Texas Center for Learning Disabilities, led by the University of Houston, has played a role in all of those findings. Now it is leading research to help older children, develop new methods of intervention and identify the genetic and environmental bases of learning disabilities.
The center, created in 2007 with a $7 million grant from the National Institute of Child Health and Human Development and renewed in 2012 with a $9 million grant, focuses on reading disabilities, a field in which Jack Fletcher, principal investigator for the center, has worked since he was a graduate student 30 years ago. It is part of the Texas Institute of Measurement, Evaluation and Statistics (TIMES), which is directed by David Francis, a co-investigator of the center grant.
Reading problems are the most commonly identified learning disabilities in the United States, says Fletcher, Hugh Roy and Lillie Cranz Cullen Distinguished Professor and chair of the UH Department of Psychology. But there is no single accepted number for how many people are affected.
“There’s nothing magical about how you define it,” he says. “There is no biological marker. It’s the lower end of reading ability.”
“While learning disabilities can’t be measured by a blood test or other common biological marker, they are linked to brain development.”
How much of that is due to genetics and how much to a child’s environment isn’t clear, and Fletcher says the two are linked, at any rate.
“We know reading problems run in families, and they are heritable,” he says. “However, if a child grows up in a home where there is no reading, the brain may not develop optimally.”
The center is one of four nationally selected and funded by the National Institute of Child Health and Human Development, part of the National Institutes of Health, to expand the understanding of learning disabilities, which affect the ability to read or understand language, do mathematical calculations and other tasks. Learning disabilities usually aren’t recognized until a child starts school.
Until about a decade ago, learning disabilities were identified by comparing scores on intelligence and achievement tests. If the IQ score was higher than that on the achievement test, the student was considered to have a learning disability.
Some of the center’s early work centered on demonstrating that isn’t a valid hypothesis, Fletcher says; new approaches stress Response to Intervention, or RTI, suggesting diagnostic decisions should be based on how students respond to efforts to teach them.
The Texas Center for Learning Disabilities takes an interdisciplinary approach to the classification, early intervention and remediation of learning disabilities, including the use of brain imaging, and work both in the lab and in elementary school classrooms in Houston and Austin. In addition to researchers based at UH, it includes researchers from The University of Texas Health Science Center at Houston and UT-Austin. Tutors — often retired teachers — deliver the interventions in the classroom.
Sharing what it has learned is a key goal, and the center has funding from the Texas Education Association to disseminate its research and train teachers to use it.
After early work with students in kindergarten through second grade, and later in middle schools, center researchers now are focused on students in third, fourth and fifth grades.
Early intervention offered dramatic results — researchers screened all children in a class and focused interventions on those in the lower 15th to 25th percentile of reading ability; by the end of the year, only two percent of those students remained at the bottom of the class.
Imaging studies, done at UT Health and UT Austin, have shown that a distinctive neural network is required for efficient reading and comprehension. When the intervention is successful, imaging has shown the normalization of this network.
With the value of early intervention widely accepted, the next frontier is improving interventions for older children. That’s more difficult, as older students with reading disabilities generally haven’t had the practice required to spur the necessary brain development.
“The catch-up is steep,” says Paul Cirino, a neuropsychologist who heads one of the center’s projects.
And by the last half of elementary school, students with reading problems are falling behind in other subjects as well, a result of their inability to read grade-level textbooks.
“Word knowledge,” it turns out, translates to “world knowledge.”
“They don’t know as much about the world as students who have been reading for years,” says Jeremy Miciak, a research assistant professor in the psychology department.
The center’s tutors address that during the interventions, which involve students enrolled in the program — the cutoff point has varied over the years but now is at those in the lowest 25 percentile — meeting for an hour after school.
A number of strategies have been tested; Miciak says researchers now use an organic approach built around practice rather than specific step-by-step strategies. Mostly, the students read — word lists and books, both at the students’ reading levels and “stretch” books, including social studies and science textbooks.
“We know one of the important ways to build reading fluency is lots of practice,” Miciak says. “One of our big areas of focus is to provide lots of opportunities.”
Cirino, director of the Developmental Neuropsychology Lab at UH and an associate professor of psychology, runs the Executive Functions Project at the Texas Center for Learning Disabilities, started in 2012, to more clearly define executive function — traditionally thought of as a “frontal lobe function” but also as the psychological and cognitive processes that help people attain goals — and establish how it relates to reading.
The project involves more than 800 third, fourth and fifth graders in Houston and Austin. After two years of gathering data, researchers are analyzing it to learn how the components of executive function relate to reading, as well as to math and language.
The goal isn’t to “fix” executive function in the brains of struggling readers, Cirino says, but to use that information to help make reading interventions more effective.
That’s the ultimate goal for all of the center’s projects, including a new project to study the genetic basis of learning disabilities.
Elena Grigorenko, Hugh Roy and Lillie Cranz Cullen Distinguished Professor of Psychology, arrived at UH this fall from Yale University, where she served on the faculty after earning a Ph.D. in developmental psychology and molecular genetics there. She is director of the Human Genetics Lab at UH and also holds an appointment at Baylor College of Medicine.
She was recruited by Fletcher to add a genetic component to the center’s work.
“We know they’re genetically based,” she says. “I don’t think there’s a disagreement about that. But it is one thing to know it’s inherited. It’s another to know why.”
The idea of a genetic link began in the early 1900s, when scientists in Germany and the United Kingdom noticed that dyslexia, a common reading disability, ran in families. In the 1970s and 1980s, researchers began to follow identical twins to expand their knowledge.
No specific gene has been identified, and Grigorenko says there are likely to be a number of genetic ties. She hopes to do a deep dive into what happens as children learn, ultimately seeking to identify the action at a cellular level.
That knowledge could be leveraged to create more effective instructional and pharmaceutical interventions for the most seriously affected children.
“My hunch is pharmaceutical intervention is essential for kids with severe learning disabilities,” Grigorenko says. But drugs won’t replace effective teaching.
That goes back to the center’s interdisciplinary approach, from looking at ways to identify which students have a learning disability to helping them overcome it.
Despite all the progress, Fletcher says, much work lies ahead. “It’s a marathon, not a sprint.”