"This malfunction at a low level of language processing could percolate through the entire system. This explains why the symptoms of dyslexia are so varied," Begona Diaz, from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, said in an institute news release.
The researchers conducted two experiments. First, participants were asked to perform speech-comprehension tasks. Using magnetic resonance tomography, the researchers found abnormal brain responses during tasks that required the recognition of speech sounds.
In contrast, when the participants only had to listen to speech sounds and not perform a certain task, the researchers found no differences between the people who had dyslexia and those who didn't.
"The problem, therefore, has nothing to do with sensory processing itself, but with the processing involved in speech recognition," Diaz explained. "Recognizing the cause of a problem is always the first step on the way to a successful treatment."