Researchers Find a Biological Marker For Dyslexia In Kids

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Detecting the reading disorder as early as possible may help more children to overcome reading and learning problems.

About one in 10 people suffer from dyslexia, the reading disability that does not impair thinking processes or  overall intelligence, but hampers the ability to process written language, often making it difficult to rhyme, determine the meaning of a sentence, and recognize words.

In the latest study, researchers from Northwestern University identified a biological process that could be responsible for the compromised reading. According to the study authors, there is a relationship between a person’s ability to read and how their brain encodes sounds.

The researchers, who reported their findings in the Journal of Neuroscience, recorded the automatic brain wave responses of 100 kids aged six to 13 as they heard speech sounds. The brains of the more adept readers encoded the sounds, or processed the speech into brain waves, in a more consistent way than those who struggled to read. The latter group tended to show more erratic and fluctuating patterns, which understandably meant that their brains were less able to consistently connect sounds with words. That in turn could interfere with their ability to read, since reading in part involves a virtual hearing of printed language. “Understanding the biological mechanisms of reading puts us in a better position to both understand how normal reading works and to ameliorate it where it goes awry,” study author Nina Kraus, a professor of neurobiology, physiology and communication at Northwestern University said in a statement.

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According to the researchers, people learn language skills by making meaningful associations between sounds and information. The most difficult sounds for the brain to encode are consonants, which are shorter and contain more complex sounds compared to vowels, which tend to have longer and simple intonations. More stable brain responses to these sounds can lead to easier interpretation of both aural and written words.

“[Some] kids are not making robust sound-to-meaning connections in language because of the way the nervous system is set up,” says Kraus. “The nervous system is responding inconsistently,” and that may set the stage for dyslexia.

The findings support other work that found that children with dyslexia show difference in brain MRI scans, even before they learn to read; the patterns could reflect differences in the way their brains process sounds.

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Finding such abnormal brain patterns may help parents and teachers to identify children who are likely to develop the reading disorder earlier, which is important since children can be trained to develop more consistent and stable sound processing. In fact, in previous research, Kraus and her colleagues showed that kids with trouble reading can use listening devices that transmit their teacher’s voice directly into their ears. Children wore these devices for a year and showed improved reading skills. Highlighting the most important sound—the teacher’s voice sounding out words—appeared to help the children better match sounds to words by minimizing extraneous sounds that could distract them.

Taken together the results of Kraus’ two studies provide hope for at least limiting some of the more severe learning problems that can come with dyslexia; if children are helped early enough with the proper training, reading could become as smooth and as natural as it is for those without the disorder.