June 1, 2005

New Clues to the Roots of Dyslexia

Sensory, rather than visual deficits, may be to blame

HealthDay News -- A problem in basic sensory perception may be at the root of dyslexia -- a learning disorder that causes reading and spelling problems -- according to a new study.

The University of Wisconsin-Madison (UWM) and University of Southern California study contradicts the popular theory that deficits in certain visual processes result in the problems experienced by people with the disorder.

The study, published online in the May 29 issue of Nature Neuroscience, also suggests new methods of identifying people with dyslexia, as well as new ways to assess techniques used by teachers to help dyslexic students.

Study author Anne Sperling said that misfiring neurons may make it difficult for people with dyslexia to distinguish relevant visual and auditory cues from surrounding sounds and patterns -- so-called "noise." This deficit may make it difficult for a dyslexic child to learn to read.

"We really want to understand what is going on at the neurological level that's leading to reading problems. (We think) that if a child has a hard time ignoring 'noise,' it could distort speech perception and complicate (the recognition) of sound segments, which is essential for learning how to read," study co-author Mark Seidenberg, a UWM psychology professor, said in a prepared statement.

Sperling offered an example of a possible immediate classroom application of this study's findings. She suggested that teachers could, "accentuate differences between sounds, showing the extremes to help (dyslexic children) build categories."

Between 5 percent and 10 percent of children in the United States have dyslexia, Sperling said.

More information

University of Wisconsin-Madison

University of Southern California

The U.S. National Institute of Neurological Disorders and Stroke has more about dyslexia.