Semantic access processing in a supra-modal deficit: A single case study

The case is presented of a semantic dementia patient, who shows a deficit selective for (i) conceptual class (living things), (ii) attribute processing (visual features) and affecting (iii) input-output modalities at the same processing stage (matching stored representation to attributes). The first experimental part aims at exploring the specific stage/process at which semantic knowledge breaks down through multi-modality tasks, devised to tap different levels within the semantic elaboration flow. The second focuses on the differences between category vs. attribute knowledge across various modalities. The core nature of the patient's deficit is investigated through a close comparison of her damage to a specific processing stage across modalities in the light of her class and attribute-specific impairment. The complex pattern of findings is discussed according to current theoretical accounts of semantic memory organization. Finally, the relevance of the adoption of a broad perspective when dealing with semantic memory impairments is highlighted. (C) 2003 Elsevier Science (USA). All rights reserved.