Deep Dyslexia - Classification

Classification

Deep dyslexia is classified as a reading disorder that is acquired in previously literate adults as a consequence of a brain injury. This injury results in the occurrence of semantic errors during reading and the impairment of nonword reading. Deep dyslexia was previously regarded as a form of acquired dyslexia as opposed to a developmental dyslexia. However, recently, developmental deep dyslexia has been more frequently reported in children with Williams Syndrome. Deep dyslexia is considered to be a "central" dyslexia as compared to a "peripheral" dyslexia. Peripheral dyslexics have difficulty matching the visual characteristics of letters that comprise a word to a stored memory of this word from prior encounters. Central dyslexics are unable to properly match the visual word to the word's meaning. They may also be incapable of speaking, or phonating, the sequence of written letters that they see into the word these letters represent. Deep dyslexia differs from other forms of central dyslexia (phonological dyslexia and surface dyslexia) in that deep dyslexics have many more symptoms and these symptoms are generally more severe. According to the “continuum” hypothesis, deep dyslexia is just a more severe progression of phonological dyslexia.