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By Steven Reinberg
WESTPORT, CT (Reuters Health) – A nonverbal audiovisual training program, in which children match shapes with sounds on a computer screen, appears to improve reading skills, as well as electrophysiological and behavioral measures, in dyslexic children, according to a report in the Proceedings of the National Academy of Sciences for August 28.
"There are two competing views of dyslexia," lead author Dr. Teija Kujala told Reuters Health. One view is that dyslexia is specific to the linguistic system, while the other view is that a more fundamental perceptual dysfunction in discriminating sensory input underlies dyslexia. "This study lends support to the latter view."
Dr. Kujala, from the University of Helsinki, and colleagues assigned 48 dyslexic children who were 7 years old to nonverbal audiovisual training or a control group. The children in the training group had 14 training sessions that were given twice a week and lasted for about 10 minutes each.
In each session, the children were asked to match a sequence of horizontal rectangles with various sounds, which were represented by different sized rectangles, or to identify the last rectangle in a sequence of rectangles.
After 7 weeks, the children who received training read significantly more words correctly compared with controls (p < 0.03) and also had a marginally significant increase in reading speed (p < 0.07), the researchers found.
To measure brain activity, the researchers recorded mismatch negativity (MMN), "which accurately reflects auditory discrimination without such biasing factors as attention, decision making or motor response," the researchers explain.
They found that MMN amplitude was considerably increased among children who underwent training compared with controls (p < 0.03). MMN amplitude was also significantly larger after training than before training (p < 0.03), while no such change was seen among controls.
"We have shown that it is possible, with training, to affect the sensory problems that underlie dyslexia and to help children read better," Dr. Kujala said. "We have also shown that the auditory system is closely related to problems of dyslexia."
Proc Natl Acad Sci 2001;98:10509-10514.