The problem of naming in SDAT: a relative deficit

Research relating to language disorder in senile dementia of the Alzheimer type (SDAT) has focused primarily on naming impairment, formally termed anomia or nominal aphasia/dysphasia. Data resulting from this research have been insufficiently informed by a comparative linguistic framework in which performance on naming tasks is contrasted with performance on other forms of language tasks. The present study involves the comparison of 21 adults with SDAT and 18 demographically controlled normal elderly adults on the Test for Syntactic Complexity and fifteen subtests of the Western Aphasia Battery. Performance on naming is compared with performance on oral language variables of repetition, yes/no response, auditory word recognition, sequential commands, syntactic processing, as well as with performance on reading tasks and non-verbal tasks. Findings relating to oral language tasks show that structured syntactic processing requiring explicit interpretation and sequential commands are significantly more difficult for the SDAT sample than are three of four naming tasks. Further, significant SDAT performance variability is found across naming tasks. The generative categorical naming task is found to be significantly more difficult for the SDAT patient than are the other three naming tasks. It is concluded that the generative categorical naming task should be regarded as a meta-naming task. In sum, it is found that although language dysfunction in SDAT has anomic components, the essential character of the language disorder is not best conceptualized as a problem of naming.