Abstract

This paper was designed to classify the symtoms of dyslexia according to the previous word recognition model. Also, research assumptions used in the study of dyslexia within modem cognitive neuropsychology are discussed. Dyslexia is divided into the developmental and acquired dyslexia. The developmental dyslexia comes from genetic disorder, whereas the acquired dyslexia is due to brain injury. The acquired dyslexia is further divided into peripheral, which does not have a direct relationship with linguistic process, and central, which is directly associated with lexical processing. This paper mainly deals with the acquired dyslexia. The peripheral dyslexia involves the neglect, attentional, and letter-by-letter reading dyslexia, whereas the central dyslexia consists of the surface, phonological, deep, reading without meaning dyslexia. The results of the study on the peripheral and central dyslexia show that the word recognition process consists of the early perceptual processing and the central lexical processing. Furthermore, the existence of phonological, surface and deep dyslexia suggests that written words are named through dual routes: the lexical and phonological-recoding routes. In classifying and evaluating dyslexia, the cognitive neuropsychological and neurolinguistic approaches are employed. These approaches are based on the research logic and concepts, such as, single case study, modularity, dissociation and association, neurological specificity or isomorphism, and transparency. The test tools developed to evaluate dyslexia are mainly based on the off-line tasks, such as, BAE, SORT, NART, WART, COWA, BNT, PPVT, and Token Test. However, in order to examine the more detailed processing deficits in dyslexia, the online tasks based on human language information processing should be developed.