CLASSIFICATION OF APHASIC CHINESE SPEAKERS - CLUSTER AND DISCRIMINANTFUNCTION ANALYSES

The Western Aphasia Battery (WAB) is a standardized aphasia test which classifies aphasias into eight syndromes based on the Wernicke-Lichth eim model, commonly known as the Bostonian model. Although the syndrom e approach has its limitations it is a widely used procedure in clinic al aphasiology as it allows users to classify patients into discrete s yndromes and to make some inference about lesion sites (Kertesz 1983). It has been shown that the Wernicke-Lichtheim framework is also appli cable in classifying aphasia in Chinese, although Chinese and English linguistic structures are very different (e.g. Naeser and Chan 1980, P ackard 1986, Gao and Benson 1990, Yiu 1992). The use of a common frame work to classify aphasia in different languages is a useful concept, a s it allows aphasia to be compared across languages. Unfortunately, ap hasia classification is not always a clear-cut procedure, and use of t he WAB is often queried regarding the validity of the quantitative cla ssification. Previous reports have shown that the agreement on classif ication using the criterion scores proposed by the WAB and that of sta tistical procedures varied from 30% to 74%. Such variability could eit her be attributed to the differences in the sample size and statistica l methods employed, or the inherent problems with the classification c riteria. This study re-examined the adequacy of the classification cri terion scores proposed by Kertesz (1979, 1982) by comparing the result s of the classification using the criterion scores (clinical classific ation) and two statistical procedures (statistical classification). Th e agreement between the clinical classification and the statistical cl assification varied between 60% and 88%. The results were interpreted to support the use of the criterion scores proposed by the WAB.