Our new article brings together four colleagues who specialize in very different areas: Jeffrey Gruen at Yale University, a pioneer in the genetics of reading disability; Jan Frijters, a Developmental Psychologist from Brock University in Canada who studies interventions for reading disabilities, Miao Li from the University of Houston a Developmental Psychologist with a focus on language acquisition, and Jeff Malins from Yale University, a Psychologist who uses fMRI and EEG techniques to understand the reading networks of the brain. Together, this interdisciplinary project sheds new light on how genes and the brain interact to produce reading function and dysfunction.
What was the main aim of your research?
The main aim of the research was to biologically characterize a lesser-known type of reading problem: children who can read individual words with age-appropriate skill levels, but who have severe difficulties comprehending what they read.
Why did you decide to explore comprehension difficulties in children?
In the early school years, learning to read letters and then words is a primary task for children. As children move through the primary grades, more and more instruction depends on children "reading to learn", which requires reading comprehension. We already know a lot from research about how to improve word reading and one of the primary things we know is that intervening early is most effective. Much less is known about how or when to intervene for reading comprehension difficulties.
Can you explain the experimental design and why this method was applied?
The experimental design on the reading skill side of things was designed to disentangle word reading skill from reading comprehension. Not a trivial task when understanding what you read depends on reading the words themselves. To do this we measured word reading skill with a test that does not depend on comprehension, and then statistically removed that skill from assessments of reading comprehension. What this gave us was an estimate of reading comprehension that was really specific to the comprehension component. It also identified this group of children who have a very different profile than children with the usual profile of reading problems. On the biological side of things, our design was to take this specific estimate and relate it to areas of the brain known to be involved in skilled reading comprehension, and to one of the genetic regions that has been repeatedly shown to be involved in reading development.
What’s the bigger picture of your research findings?
The bigger picture is that reading difficulties are complex - there is no single 'dyslexia' profile, though there are more or less common patterns. How does this relate to our gene-brain-behaviour analysis? Because reading is a complex skill that has emerged relatively late in human evolution, our brains need to co-opt functionality that was never designed specifically for reading. As a result, when reading development fails it can fail in very different ways that may be linked differently to brain and gene function.
What is the future for this field in terms of advances in research?
There is a large explanatory gap between genes and behaviour. For example, we know that reading problems are strongly heritable, but the strength of that relationship measured at the molecular genetic level is quite weak. However, the link between genes and brain function is strong, and the link between brain function and reading behaviour is also strong. When the three elements are combined analytically, this will allow us to characterize reading failure more precisely and design reading interventions that are targeted to childrens' specific difficulties.
Please read more about our study “A molecular-genetic and imaging-genetic approach to specific comprehension difficulties in children” published by the Journal, npj Science of Learning.