Poor Brain Wiring Behind Dyslexia

People with dyslexia have faulty wiring between auditory and speech regions of the brain, a new study has found.

Dyslexia is a learning disorder that affects about ten percent of children in the U.S. People with the condition have difficulty reading despite having normal intelligence.

When we learn how to read, our brain begins to connect speech with the written symbol, according to Scientific American. But, people suffering from dyslexia fail to make these connections, leaving them with limited ability to read.

A major debate among dyslexia researchers is whether people with the conditions have abnormal brains or whether the brain is unable to link symbols with words.

University of Leuven in Belgium researchers led by Bart Boets found that phonetic representations "the unique neural pattern that the brain attaches to a sound of speech" are normal in the brains of people with dyslexia. However, the brain isn't able to access these representations. 

The study was based on 22 normal and 23 dyslexic adults who were hooked on to a functional magnetic resonance imaging (fMRI) scanner while they listened to specific speech sounds.

"I was so convinced that we would observe degraded (i.e., less robust and distinct) phonetic representations in the dyslexic participants," Boets said in a press release. "Yet, their representations turned out to be perfectly intact."

Researchers then looked at neural connections between parts of brains involved with language processing and phonetic representations.

"Our findings indicate that the speech sound representations themselves are intact, but a dysfunctional connection between frontal and temporal language areas impedes efficient access to the representations," said Boets, according to AFP.

The study is published in the journal Science.