Acquired Reading and Writing Disorders

Empirical evidence indicates that while the acquisition of oral language is based on neuroanatomical and functional units that are genetically predetermined, it is difficult to apply these assumptions to written language. This chapter pursues questions such as how reading and writing are represented at a mental level and how and where is it implemented in the human brain. In the first section the classical clinical neuropsychological taxonomy of reading and writing disorders is introduced and its limits discussed, while the second section deals with the contemporary models that describe normal written language processing and analyzes the implications of a more cognitively sound description of acquired dyslexia and dysgraphia. The third section provides an overview of the major cross-linguistic differences between languages, using alphabetic and logographic scripts and the impact these differences have on reading and spelling disorders. Finally, the neuroanatomical foundations of written language arising from both the anatomo-clinical correlative approach and functional neuroimaging studies are discussed.