dyslexia in China

from Science News:

Cultured Readers: Chinese kids show new neural side of dyslexia

Bruce Bower

A group of Chinese grade-schoolers with severe reading difficulties has taught scientists an intriguing lesson: Brain disturbances that underlie the inability to read a non-alphabetic script, such as Chinese, differ from those already implicated in the impaired reading of alphabetic systems, such as English.

Neuroscientist Li Tai Han of the National Institute of Mental Health in Bethesda, Md., and his colleagues say their data challenge the view that the reading difficulties considered central to dyslexia spring from a common biological source (SN: 3/31/01, p. 205: Available to subscribers at http://www.sciencenews.org/articles/20010331/note13.asp). "Rather than having a universal origin, the biological abnormality of impaired reading is dependent on culture," the investigators conclude in the Sept. 2 Nature.

Prior brain-imaging studies of dyslexia among readers of letter-based languages have highlighted disturbances in a brain network with its hub in tissue toward the back of the left hemisphere (SN: 5/24/03, p. 324: http://www.sciencenews.org/articles/20030524/fob4.asp). Scientists have tied that neural region to the ability to match written letters to corresponding sounds.

In Chinese readers with dyslexia, however, the locus of trouble lies in a vertical fold of tissue near the front of the brain. This area assists in recognizing sounds and meanings denoted by Chinese characters and other abstract symbols, Han and his coworkers say.

They studied 16 children, ages 10 to 12, who attended a Beijing elementary school. All the youngsters scored well on intelligence tests, but half of them had severe reading problems.

A functional magnetic resonance imaging (fMRI) scanner measured blood flow throughout each child's brain during two experiments. In one of them, kids judged whether pairs of Chinese characters presented on a computer screen had the same pronunciations. In the other test, children tried to discern whether each of a series of written characters was a real Chinese character or a fake one with no designated meaning or pronunciation.

Compared with the fMRI scans of good readers, the scans of poor readers indicated substantially lower blood flow, and therefore reduced brain-cell activity, in and around the left-brain tissue fold. Several other left-brain areas associated with reading non-alphabetic script also showed minimal activation in poor readers. In addition, two right-brain areas involved in the visual analysis of written characters displayed weak activity in poor readers.

Similar findings emerged in an unpublished brain-imaging study of 65 more Chinese children, Tan says.

Neuroscientist Guinevere Eden of Georgetown University Medical Center in Washington, D.C., says that the new study shows how different writing systems can direct the development of distinct brain networks for reading. [ed.: NAAR funded her research back when I was on the board. She was great.]

It's too early to say whether different writing systems fundamentally change dyslexia's neural basis, cautions Bennett A. Shaywitz of Yale University Medical School. He notes that Tan's "milestone" fMRI data also reveal that several brain regions for dyslexia are common to children in China and the United States.

Tan argues that his findings of cultural differences in dyslexia's biology are sound. One test, he says, would be to see whether English readers with dyslexia profit from instruction in recognizing whole words, as Chinese readers do. [ed.: haven't we already had this test for the last 100 years?] This might open an otherwise-unused neural pathway to effective reading.

So....I guess Li Tai Han hasn't heard of the reading wars.

sheesh


teach them Italian

Here's the answer:

Dyslexia gets a break in Italy

Bruce Bower

Although people with the reading and language disorder known as dyslexia exhibit a common disruption of brain activity, their performance on reading tests varies greatly from one country to another, according to a report in the March 16 Science.

There's a simple reason why individuals with dyslexia read better in certain countries, according to neuroscientist Eraldo Paulesu of the University of Milan Bicocca in Italy and his coworkers. Those who read languages such as Italian—in which specific letter combinations almost always stand for the same sounds—have the advantage over those who read languages with less-consistent spelling rules.

In English and French, for example, the same letters often have several associated sounds (as in mint and pint or cent and cat in English) or different letters for the same sounds (as in au temps and autant in French). For dyslexics, such languages are obstacle courses of spelling irregularities.

In another part of their study, Paulesu and his coworkers used positron emission tomography scanners to measure blood-flow changes in the brains of 72 adults as they read real and nonsense words in their native languages. Equal numbers of volunteers came from England, France, and Italy. Half from each country had dyslexia.

All dyslexic readers exhibited the same pattern of reduced left-brain activity, as indicated by drops in blood flow in that part of the brain. Despite this evidence for a common neurological flaw in dyslexia, however, those from Italy scored much higher than their European counterparts on a reading test.