PUB - Publikationen an der Universität Bielefeld

In aphasic patients, word-finding difficulties occur in a variety of situations and have been extensively studied in picture confrontation naming with oral response. However, systematic research of naming disorder focusing on the Chinese language can seldom be found. This study, firstly, constructs a systematic assessment of word processing disorder of aphasic patients in the framework of cognitive psycholinguistic models of language processing and secondly, evaluates the relative adequacy of module and neural network models of language processing to explain word processing patterns exhibited by Chinese-speaking aphasic patients. In the theoretical review the components and major features of three significant models of language processing were described: the logogen model (Morten, 1980;1984), Levelt's model (Levelt, 1989;1992;1993) and the connectionist models or the neural network theory (Dell & O'Seaghdha, 1992; Schade, 1992; Harley, 1996). Their assumptions on the location of naming disorder were compared. To test the applicability of these cognitive processes to Chinese word processing, extensive cross-modality tasks concerning the mental process of linguistic knowledge at different levels of language system were constructed. The performance of 10 normal subjects and 26 aphasic subjects were investigated and compared. The profile of these patients' performance shows a diversity of patterns of deficit with the convergence of disorder of the components of the language system and the disorder of processing of this information. The types of errors produced by these patients are interpreted in terms of the presented three models. It shows that the logogen model is quite helpful for an overview of the preserved and impaired linguistic competence of the patient. However, in various aspects the logogen model can not provide explanations for the errors produced by these Chinese-speaking aphasics, whereas Levelt's model and the connectionist models can account for the error types more precisely. Based on the result of this study, a model of Chinese word processing concerning the linguistic functions explored in this study was proposed. The central assumptions of this account are: (1) The modality-specific form representations of a word are independently stored in separate components. (2) Phonological-lexem and orthographical-lexem are independently activated by semantic representation. (3) The selected lexical-semantic representation activates in parallel all the lexemes of words that constitute or share semantic features with the selected lemma. (4) In the process of repitition the semantic representation may interact with sublexical phonological information. (5) Speech production errors can be monitored through the device of the short-term memory buffer and the feed-back loop from it to other corresponding components. The results of this study advance our understanding of the processing of recognition, naming and repitition of Chinese words. The features of this model allow testing a number of issues in word processing, thus contributing towards a more valid theory on the processing of words. The model-based assessment can be regarded as the foundation of a screening of naming disorder, specifically for Chinese languages. The theoretical framework may be applied in the modeling of language processing as well as in the assessment of language competence in psycholinguistics and language acquisition respectively.