Dyslexia in chinese

Dyslexia in symbolic languages has different neural causes than dyslexia in letter languages

Dyslexia may not have a universal cause, it could be conditioned differently depending on the culture. This is what a team of researchers from the Department of Linguistics at the University of Hong Kong and the National Institute of Mental Health in Bethesda found when they tested Chinese children suffering from dyslexia. In the latest Nature, the group reports their findings.

Once a dyslexic, always a dyslexic

Dyslexia is one of the most common disorders in school achievement. Approximately 5 percent of students in a grade are affected. They falter when reading, omit words, letters or syllables or mix them up. In addition, there are grammatical and punctuation errors. Dyslexics have difficulties learning to read, but this does not make them dumber, less able to learn or even lazy. Even if there are ways to train against reading weaknesses: Dyslexics remain dyslexics for life.

Searching for traces in the brain

The causes of dyslexia have not yet been adequately researched. However, using imaging techniques (magnetic resonance imaging, MRI), scientists have already been able to track down brain regions that are thought to play a role in this process. According to this, dyslexia could be a dysfunction of certain areas of the left hemisphere of the brain, namely the temporo-parietal cortex, which showed a lower activity in dyslexics than in subjects without reading difficulties. In addition, it was previously amed that the causes of dyslexia are universal, i.e. the same in all cultures.

Dyslexia in Chinese

Brain regions with conspicuous activity in language processing and the conversion of Chinese characters into speech in healthy and dyslexic subjects

Since not all languages function in the same way, it was obvious to ame that such a generalization would not necessarily be correct. While European languages are based on an alphabet, in which letters are translated into sounds in the course of reading, in order to bring them into a semantic context in a further step, in logographic languages such as Chinese characters are not connected with sounds. There, characters must first be associated with a word syllable.

The glow in the frontal gyrus medialis

Researcher Li Hai Tan and his colleagues have now used computed tomography to study the brain activity of Chinese children with reading disabilities to see if the same areas of the brain are affected in Chinese dyslexics as found in previous Western studies. They tested 16 schoolchildren, half of whom suffered from dyslexia, the other half did not.

They found that the activity of the temporo-parietal cortex was similar in all children. However, a difference was found in another area of the brain: the so-called middle frontal gyrus (gyrus frontalis medialis) of the left hemisphere of the brain worked much more weakly in the dyslexic children, whereas a stronger activity was observed in a section of the left prefrontal cortex.

Different language, different cause

The left middle frontal gyrus plays an important role in the analysis of Chinese characters; it is the center for fluent reading of Chinese characters. Visual impressions are more likely to be processed in the left prefrontal cortex. Scientists now suspect that Chinese children with dysfunction of the left middle frontal gyrus have difficulty with characters and try to compensate by increasing the activity of the visual system.

With their results, the researchers also see it as proven that the reading difficulties in Chinese and American children are based on different neurological causes and that dyslexia cannot therefore have a universal cause. They now hope to use their knowledge to develop more targeted exercises that stimulate this region of the brain more strongly, so that sufferers can compensate for their handicap in this way.

What does it mean when it lights up?

Watching the human brain at work with imaging is fascinating and it has become a popular way to detect this or that. At the same time, very different states of the brain are very close to each other. So can you always be so sure what exactly you are observing and measuring when it lights up on the screen?? It can’t hurt to always keep a little question mark in mind.