CONFRONTATION OF PDP MODELS AND DUAL-ROUTE MODELS THROUGH THE ANALYSIS OF A CASE OF DEEP DYSPHASIA

A case study is presented of a patient, EA, who demonstrated all the d efining features of deep dysphasia. His repetition disorder was associ ated with surface dyslexia and deep dysgraphia. EA also showed a sever ely restricted phonological STM. His performance in both picture confr ontation naming and writing-to-dictation paralleled his performance in repetition, whereas reading aloud and oral lexical decision were not influenced by the imageability of the word input. Further testing indi cated that EA did not have difficulty in either perceiving or semantic ally processing spoken words. An exhaustive investigation of EA's cogn itive functioning was first conducted by reference to Patterson and Sh ewell's model (1987). Such a triple-route model can account for EA's o verall performance by postulating multiple functional lesions. We alte rnatively show that EA's language profile could be accounted for withi n a highly interactive model of language processing incorporating most basic principles of connectionist-PDP models. Within this latter fram ework, deep dysphasia, surface dyslexia, and deep dysgraphia could be interpreted as originating from a single functional deficit. Our analy sis further suggests an impact of semantic and orthographic knowledge on phonological processing.