Rewiring the Dyslexic Brain

Dyslexia can be a real difficulty for many children, although for many it has been a gift: they have succeeded very well in life by mobilizing other psychological and neurological resources. Sir Richard Branson, the founder of Virgin Enterprises, Thomas Edison and Albert Einstein are all said to have had dyslexia.

There are many types of dyslexia, but in the most common – developmental dyslexia – children confuse letters and syllables when they read.

It now appears that some children with dyslexia struggle to read because their brains are not correctly wired to process fast-changing sounds, according to a study published this month in the journal Restorative Neurology and Neuroscience.

However sound training using computer exercises was able to rewire children’s brains, correcting the sound processing problem and improving reading.

More than 30 years ago Paula Tallal of Rutgers University proposed that children with dyslexia might have an underlying problem processing sound, but it has never been tested using brain imaging. The researchers used functional MRI imaging (fMRI) to examine how the brains of twenty two 9- to 12-year old children with developmental dyslexia, and normal readers, responded to sounds, both before and after using educational software called Fast ForWord Language.

The first test involved measuring how the children’s brains responded to either fast-changing or slow-changing sounds that resembled speech. The fast-changing sounds altered in pitch or other acoustic qualities quickly. In just tens of milliseconds, as occurs in normal speech. The slow-changing sounds changed over only hundreds of milliseconds.

In normal 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 did not stimulate high levels of activity in these regions of the brain. Instead, dyslexic children processed the fast-changing sounds as if they were slow changing. They used the same regions of the brain but at lower intensity.

We know that infants must correctly process fast-changing sounds as they learn language. They use sound processing to create a sound map of their native language. If they are unable to analyze fast-changing sounds, their sound map may become confused. The idea is that they run into trouble when they first see printed letters because the children’s brains now try to match their internal sound map to letters that they see on the page. Linking normal letters to confused sounds may lead to syllable-confused reading.

But the brains of the children with dyslexia changed after completing exercises in a computer program known as

The Fast ForWord Language program does not involve reading at all, but only listening to sounds, starting with simple, changing noises, like chirps that swooped up in pitch. The children then have to respond with a clicker when the chirp’s pitch goes up or down. At first the sounds are played slowly, but they gradually speed up, becoming more challenging for dyslexic children. The exercises are then repeated with increasingly complex sounds: syllables, words, and finally, sentences.

The fMRI study showed that these repetitive exercises appeared to rewire the dyslexic children’s brains: after eight weeks of daily sessions – about 60 hours in total – their brains responded more like the brains of typical readers when they were processing fast-changing sounds, and at the same time their reading improved.

It is still early days for this research, and we do not yet know whether the improvements in reading and in the brain will be sustained.

This research may make it possible to identify children at risk of dyslexia even before they start learning to read. It is also possible that other approaches to learning sounds, such as learning to sing or play an instrument may be effective, since most of us learn music with gradual, repetitive, and intense listening and move up to faster changing sounds.