Researchers in the Department of Pediatrics at Yale have identified a disruption in the neural circuitry for reading in the brains of dyslexic children as young as age seven.
Published in the July 15 issue of Biological Psychiatry, the study's authors used functional magnetic resonance imaging (fMRI) to examine the neural circuitry for reading in 144 children ranging in age from seven to 18. The study included children who were good readers and those who had reading disabilities.
"We previously demonstrated a disruption in the neural circuitry of adults, but we did not know if this disruption was just the end result of years of poor reading or if it was there from the beginning of the time a child should be able to read, which is around six or seven years old, so our study begins at that point," said study co-author Sally Shaywitz, M.D., professor of pediatrics at Yale School of Medicine and co-director of the Yale Center for the Study of Learning and Attention.
The team was able to find a region in the brain that relates to skilled reading. The better a child is reading, the more activity there is in this brain region. "If the child is given a reading test and scores high, then that region of the brain is more likely to be active," said the study's first author, Bennett Shaywitz, M.D., professor of pediatrics and neurology and in the Yale Child Study Center "This is the area that is disrupted in children who are dyslexic."
Bennett Shaywitz said that in good readers, there are certain areas on the left side of the brain that are activated, and in dyslexic children, there's a disruption in the back of the brain on the left side. He and his team were able to identify compensatory regions in other areas of the brain that dyslexic children use to read. "Dyslexic children can't use the highly specialized area that is activated in good readers and therefore don't read automatically or fluently," said Shaywitz. "But because they develop compensatory systems on the front and the right side of the brain, they read more accurately over time, but remain slow readers. This study shows how the children can compensate, but it also shows the limitation of that compensation."
Bennett Shaywitz said dyslexia is a very common disorder affecting one out of five American children. It is a hidden disability and there are very few families who haven't been affected by dyslexia. The disorder can be found equally in children who have average intelligence and children who are very bright.
"It's a very important public health issue because it affects so many children," said Bennett Shaywitz. "It affects children throughout their lives, and it has such an impact because in our modern society everything we do, we do through reading. All the information we take in, is done through reading. Since the disruption is evident early on and persists, it is urgent that children be identified and receive effective reading programs when they first begin school."
"Before fMRI became available, there was no way to see inside the skull to see the brain at work," Bennett Shaywitz added. "This can make a huge difference in our ability to understand and to see the mind at work."
Other authors on the study included Kenneth R. Pugh and W. Einar Mencl of the Department of Pediatrics and Haskins Laboratories at Yale; Robert K. Fulbright, Pawel Skudlarski and R. Todd Constable of the Department of Diagnostic Radiology at Yale; Karen E. Marchione of the Department of Pediatrics at Yale; Jack M. Fletcher of the Department of Pediatrics at the University of Texas Medical School-Houston; G. Reid Lyon of the Child Development and Behavior Branch of the National Institute of Child Health and Human Development, National Institutes of Health; and John C. Gore of the Department of Diagnostic Radiology at Yale and the Department of Applied Physics.
Contact
Karen Peart
203-432-1326