Dyslexia isn’t limited to the written word. Children with this disorder also respond differently to speech, finds a brain scan study from the University of Texas in Houston. When hearing spoken words, dyslexic children do not use the area of the brain traditionally responsible for speech recognition. This change apparently makes it difficult for them to distinguish similar sounds.
Study coauthor Joshua Breier, a professor in the department of neurosurgery, measured the brain activity of dyslexic and non-dyslexic children as they distinguished syllables that sound alike such as 'ga' and 'ka'. Normal children showed activity in the left lobe, specifically in the temporoparietal areas found on the surface of the back of the brain. This area is known to control phonological processing, which is key to developing reading skills.
Dyslexic kids did not have the same spike of activity in the left lobe, but a corresponding area in the right hemisphere peaked at relatively higher levels. Researchers don't know what this area of the brain does. Breier suggests that the right lobe may be attempting to compensate for the left lobe's inaction.
