Study Suggests Dyslexia Varies Around the Globe
Dyslexia looks distinctly different in Chinese speakers than it does in American children, a new study says.
In the U.S., children who are dyslexic have trouble detecting or manipulating the sound structure of oral language, according to a report on the study posted this week in the "Science Daily" blog, and that, in turn, leads to problems mapping speech sounds onto letters.
In China, though, dyslexia is both a phonological problem and a visuospatial disorder, says this group of researchers from the University of Hong Kong. That's due in part to structural differences in the languages. They write:
"Written Chinese maps graphic forms—i.e., characters—onto meanings. Chinese characters possess a number of intricate strokes packed into a square configuration, and their pronounciation must be memorized by rote."
That means the Chinese readers must rely more heavily on visuospatial processing than do readers of English. To test that idea, the researchers asked normal and dyslexic Chinese readers to judge the size of visual stimuli. In keeping with their theory, they found that nondisabled readers excelled at that task.
But the really interesting finding in this study is that brain scans of both types of readers also showed that the dyslexic readers exhibited weaker activation in the part of the brain that governs visual processing.
The original article appeared in the Oct. 12 edition of Current Biology.
Li Hai Tan, the lead researcher on the project, said the findings suggest the need for a unifying theory of dyslexia that might encompass a fuller range of variations of the disorder. This might be worth noting, too, for special education teachers and other educators who work with young children born speaking a language that is as visually different from English as Chinese is.