Psychologists in the US measured 36-hour-old infants' brain activity as they listened to sounds and recorded the brainwave patterns formed.

They then monitored the children's IQ every two years until the age of eight.

Several differences in the brainwave patterns of the newborns singled out the future dyslexics from the better readers.

However, some of the better readers also had brainwave differences leading the researchers to call for further studies.

Early detection

The work, led by Dr Dennis Molfese, at Southern Illinois University in Carbondale, is reported in New Scientist magazine.

The study looked at 186 newborns

In most cases dyslexia is not detected until school age.

"By this time, children's minds are not so flexible and they find it harder to master new skills," Dr Molfese, told the magazine.

However, he was aware that the test would need to be fine-tuned.

"What is needed now is a prospective study of the same brain patterns in other samples, to see if they are reliable," said Dr Molfese.

Treatment

He is persuaded by studies that suggest that dyslexia partly arises from early hearing problems, and suggested that infants who look likely to develop the disorder following the test could be fitted with a special hearing aid to accentuate the differences between speech sounds.

Rod Nicolson, a dyslexia specialist at Sheffield University, said the unreliability of the test might cause unnecessary anxiety for children and parents, although the approach had potential.

But he disagreed with the idea of special hearing aids, believing that interference with normal hearing could slow down the rate at which children acquired language.