Decoding Dyslexia

Your brain is multitasking as you read this article. It’s recognizing shapes on the page as letters, translating those letters into sounds and words, and ascribing meaning to them. For most people, the skill becomes automatic during grade school. But for people with dyslexia, reading takes effort.  Jason Yeatman wants to understand why.

Yeatman, assistant professor of speech and hearing sciences and a researcher with the Institute for Learning & Brain Sciences (I-LABS), uses magnetic resonance imaging (MRI) to study the brain processes involved in reading, with a focus on dyslexia. “You can observe a child struggling to read, but looking at the structure and function of the brain opens up new understandings of why that is,” says Yeatman, whose studies involve both children and adults.

Reading is a relatively new function for humans. Though Homo sapiens evolved specialized brain regions to communicate through language, evolution has not caught up with reading. “It is a made-up human invention, and it’s only been around for a few thousand years,” says Yeatman. “We teach our children this arbitrary system of printed symbols, and assign sounds to each symbol, and we use that to represent language in a totally new way. And their brains learn to do it really well most of the time. Understanding how the brain accomplishes this is fascinating. It requires the integration of many different kinds of brain functions. It’s a model for how the brain learns to do all kinds of new things.”

Thanks to recent advances in non-invasive brain imaging technology, Yeatman’s research team at the I-LABS Brain Development & Education Lab is able to study developing brains to identify changes as children acquire reading skills. The team measures both the structure of the brain and how the brain functions while someone is reading. A major component of the work is the development of software to measure properties of human brain tissue, localize abnormalities, and quantify changes that occur.

For one National Science Foundation-funded study, the team uses MRI technology to study children with dyslexia as the children participate in an intensive eight-week reading intervention program. By taking MRI measurements of the children’s brains throughout the intervention program, the researchers hope to determine how the process of learning to read changes the brain, as well as how a child’s unique pattern of brain anatomy predicts their success with the intervention.  

“Right now we’re studying 50 children,” says Yeatman. “If we can find indicators of likely success through intervention, the next step will be to test a larger sample and start making useful predictions, such as who will benefit from which intervention program. We’re trying to understand individual differences among children with dyslexia, working toward the idea of personalized intervention programs based on brain measurements.”

In a separate study funded by the Microsoft Advanced Reading Technologies group, the research team is focusing on the visual system involved in reading, and how that may be wired differently in some people with dyslexia. Yeatman believes that simple manipulations — changing the fonts on a computer monitor, for example — may make a difference for some people. “It wouldn’t be a silver bullet that cures dyslexia, but for some people it could subtly help with the learning process,” he says.

While Yeatman’s research is not yet ready for clinical application, he hopes it may eventually expand treatment options for dyslexia. His department’s Speech and Hearing Clinic, which offers a variety of language-related services to the community, inspires him to keep clinical possibilities in mind while conducting research. “It’s a wonderful thing that my life gets to be split between fascinating basic science questions about the brain and questions about how the research could actually be brought into the clinic,” says Yeatman.   

Working with children and adults with dyslexia, and seeing how the learning disorder affects their lives, has added an urgency to Yeatman’s research.  

“For some people with dyslexia, it doesn’t end up being a profoundly limiting thing in their life, but for others it really does,” he says. “Some really smart kids have self-esteem issues because of dyslexia and are unable to appreciate all the things they’re really good at. The interesting thing is that the more I learn, the more I notice how many people around me are dyslexic. Good friends, colleagues, brilliant scientists with dyslexia have been subjects in my studies. It’s important to understand that it’s not an indication of intelligence. It’s a totally different aspect of the brain.”