The study, published in Restorative Neurology and Neuroscience, found fast-changing sounds don't trigger the brains of children with developmental dyslexia to show a high intensity activity seen in the brains of typical children and so may lead to confused syllable reading.
"Children with developmental dyslexia may be living in a world with in-between sounds," lead study author Nadine Gaab, of Children's Hospital Boston. "It could be that whenever I tell a dyslexic child 'ga,' they hear a mix of 'ga,' 'ka,' 'ba,' and 'wa.'"
Gaab watched -- using brain functional magnetic resonance imaging -- as children listened to the sounds through headphones.
In typical readers, 11 brain areas became more active when the children listened to fast-changing, compared to slow-changing, sounds. In dyslexic children, the fast-changing sounds are processed as it they were slow-changing sounds. But the brains of the children with dyslexia changed after completing exercises in a computer program known as Fast ForWord Language. The exercises involved no reading -- only listening to sounds.