Intact but Less Accessible Phonetic Representations in Adults with Dyslexia

People with dyslexia seem to have difficulty identifying and manipulating the speech sounds to be linked to written symbols. Researchers have long debated whether the underlying representations of these sounds are disrupted in the dyslexic brain, or whether they are intact but language-processing centers are simply unable to access them properly. This study indicates that dyslexia may be caused by impaired connections between auditory and speech centers of the brain. The researchers analyzed whether for adult readers with dyslexia the internal references for word sounds are poorly constructed or whether accessing those references is abnormally difficult. Brain imaging during phonetic discrimination tasks suggested that the internal dictionary for word sounds was correct, but accessing the dictionary was more difficult than normal.