Understanding Brain Function in Dyslexia

Approximately three to six percent of all school-aged children have developmental dyslexia, a learning disability that specifically affects reading. While they are generally bright and capable in other areas, dyslexic children struggle with basic word recognition skills. Without early diagnosis and intervention, they may never achieve adequate reading skills.

Past studies of dyslexic and normal brains, using other imaging techniques, suggest links between brain structure and reading disability. It is believed that very few children with reading disabilities have difficulty processing the visual-spatial information needed to see words or letters in proper shape or order. Instead, most have phonological problems, or difficulty processing language-sounds. These problems are known to be strong predictors of reading disability and will persist even after adequate reading levels are reached.

A Medical College of Wisconsin research team is using the latest functional magnetic resonance imaging (FMRI) technique to compare the brain activity of dyslexic adolescents to that of non-dyslexic peers. Seeing how they differ when processing language sounds may help reveal the cause of dyslexia, laying the groundwork to develop more effective interventions. Jeffrey Binder, MD, Associate Professor of Neurology at the Medical College and a neurologist with the Froedtert & Medical College Neurosciences Center, is principal investigator in the ongoing research. His team is studying the nature and extent of brain function differences when children make use of language-sounds, or phonological information, to process written or oral language.

The FMRI technique that the team members use shows the precise location and sequence of brain activity as it occurs. It is painless, non-invasive and involves no x-rays radiation, drugs or dyes. During the imaging, the children are asked to push a button to respond to different sounds that test phonological skills essential to reading. These include an awareness or understanding of the sound structure of language, the ability to convert the printed word into a sound-based representation and the silent sounding-out of printed words for storage in working memory.

The team hopes to identify brain regions involved in reading and to lay the foundation for using FMRI to improve diagnosis and treatment of developmental dyslexia. Other members of the research team include Medical College neuropsychologist Robert Newby, PhD, and research technologist Julie Frost, MS.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.