Dyslexia might be different depending on the language

Westerners shudder at the idea of reading even the most basic street signs and instructions in Chinese, a language with 6,000 characters to memorize to be considered fluent.

A new set of brain images shows why: Reading English-style alphabets and Chinese characters use very different parts of the brain.

The results suggest Chinese students with reading problems misfire in a different brain region than the one used in reading alphabet-based languages like English.

This demonstrates that the learning disorder dyslexia is not the same in every culture and does not have a universal biological cause, researchers said.

Neurologists described the results as "very important and innovative." While dyslexia has certain common roots, they said they now have proof this kind of functional problem plays out differently according to the unique demands Western and Eastern languages place on the brain's wiring and processing centers.

And, it suggests treating dyslexia around the world probably will require different therapies between nations and languages, they said.

"We should not be alphabet-centric in our thinking," said Georgetown University neuroscientist Guinevere Eden. She has conducted brain scans on American dyslexic children, but she did not participate in the study on Chinese students.

Dyslexia is a common developmental disorder in which people of normal intelligence have difficulty learning to read, spell and master other language skills. In the United States, it is observed in 5 to 15 percent of the population, while in China it affects up to 7 percent.

Earlier brain scans show English-reading dyslexics misfire in the left temporal-parietal region of the brain associated with awareness of phonemes, 44 sounds from the English alphabet.

And, according to the new study, it uses some different brain parts, called the left middle frontal gyrus, or LMFG.

Brain scans show the LMFG fires in normal Chinese readers, but Chinese dyslexics show glitches in that circuitry, according to Li-Hai Tan of the National Institute of Mental Health in Bethesda and the University of Hong Kong.

Tan's results appear in the latest issue of the journal Nature.

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