Reading and Writing Impairments

Abstract

  The author described a classification of acquired alexia and agraphia from a viewpoint of neuropsychology or lesion-to-symptom-based neuroanatomy. Cognitive neuropsychology divides alexia into a central type (impairment at a level of lexical or phonological processes from visual recognition) and a peripheral type (impairment of visual recognition) . The central type alexia is further divided into phonological dyslexia, surface dyslexia and deep dyslexia. Similarly, agraphia is divided into a centra (llinguistic) type (impairment of lexical or phonological processes) and a periphera (lmotor) type (impairment at a level of converting visual and kinesthetic information into spelling movement) . The central type agraphia consists of phonological agraphia, lexical agraphia and deep agraphia, whereas the peripheral agraphia consists of apraxic agraphia and allographic agraphia. Neuroanatomically, alexia and agraphia consist of pure alexia, alexia with agraphia and pure agraphia, each is divided into subtypes.
  In addition, the authors recently reported a patient with selective on-reading impairment and on-reading predominance over kun-reading in semantic dementia patients. These findings demonstrate the double dissociation between on-reading pathway and kun-reading pathway.