English, French and Italian dyslexics share the same irregularity in brain function, a new research study has found. But Italian dyslexics have a much easier time reading because their language is less complex.
Researchers in Canada, France, Italy and the United Kingdom scanned the brains of French, English and Italian dyslexics searching to see whether a disorder that makes reading and writing difficult manifests itself in the same way among people who speak different languages.
They found the neurological basis of dyslexia is the same, regardless of language. Using advanced scanning techniques, they found the part of the brain that normally processes sounds is far less active in dyslexics when they are reading than in people without the disorder.
"We think the problem with dyslexia is particularly to do with the sounds," British researcher Chris Frith said in an interview.
"You can show in some cases they not only have difficulty in reading, but have difficulty in hearing and can't repeat back nonsense words very well. It is particularly difficult for them to learn how to map sounds on to letters," said Dr. Frith, who works at the Institute of Neurology in the London.
He and other members of the team, including Montreal researcher Michel Habib, found that French, English and Italian dyslexics performed equally poorly when tested on their short-term memory of sounds.
But Italian dyslexics did much better in reading tests.
The difference is that the written words in Italian correspond better with their sounds.
In English, there are 1,120 ways to represent 40 sounds, or phonemes, using different letter combinations. This makes it harder to match letters to sounds. The researchers use the example of mint and pint. It is impossible to read each correctly unless you have previously learned how they sound.
In French, 35 different sounds are described through 190 different letter combinations.
In Italian, there are only 25 different sounds, and 35 ways to represent them using different letter combinations.
"This means that the same letter groups in Italian almost always represent the same unique sound, which makes the written language logical and easy to read," the researchers said in their report, published today in the journal Science.
This means that the Italian population may have hidden cases of dyslexia, while in English and French-speaking countries, relatively mild cases of dyslexia may appear to be far more severe.
Previous research has shown that the prevalence of dyslexia in Italy is half of that in the United States.
One of the scientists, Italy's Eraldo Paulesu, argues that it could be a good idea to reform English and French to make the spelling of words more closely correspond to their sound.
But other members of the team aren't sure that's such a good idea.
"The problem with English is it is a mixture of Latin-type words that came over with the French in 1066 and German words that came over with the people before that. So it is difficult to come up with a system that would work equally well with all words," Dr. Frith said.
There is also the question of which version of English would dictate the new spelling rules.
"If you make the letters correspond to the sound, whose sound is it? Cockney? Scottish? Southern United States?"
He said Spanish ranks about the same as Italian in terms of complexity. Czech and Finnish are also considered languages where the the written word closely reflects the spoken sound.
It is estimated that anywhere from 3 per cent to 5 per cent of the population suffer from severe dyslexia, says Fran Thompson, of the International Dyslexia Association.
It didn't stop them
Many brilliant and successful people have suffered from dyslexia, a learning disability that is not related to intelligence. They include: Albert Einstein, physicist Winston Churchill, prime minister of Britain Thomas Edison, inventor Agatha Christie, mystery writer Walt Disney, entertainment giant Henry Winkler (The Fonz), actor Charles Schwab, pioneer discount broker Sir Richard Branson, CEO of Virgin Records