CATEGORY-SPECIFIC SEMANTIC IMPAIRMENT IN ALZHEIMERS-DISEASE AND TEMPORAL-LOBE DYSFUNCTION - A COMPARATIVE-STUDY

In this paper we report an in-depth case study of a patient suffering from Alzheimer's disease who presented with a category-specific disord er relating to processing of knowledge about animate objects in the pr esence of spared knowledge of inanimate objects. Impairments appeared not only in a confrontation naming task but also on a range of visual knowledge tasks, such as drawing from memory or part-whole matching. T he pattern of impairment was compared to that shown by a post-encephal itic patient who manifested a well-documented category-specific defici t for animate objects. Both patients' performance was compatible with an interpretation in terms of impairment at the level of the structura l description of objects within the semantic system, as general encycl opaedic knowledge was largely preserved. Temporal lobe damage may be t he cause of memory breakdown in both patients.