Semantic relations and Alzheimer's disease: an early and disproportionate deficit in functional knowledge.
This experiment explored knowledge of four types of semantic relations (superordinate category, part, property, and function) in Alzheimer's disease (AD) subjects and age- and education-matched controls. Moderate AD subjects showed the greatest disruption on functional relations, intermediate disruption on part and property relations, and the least disruption on category relations; mild AD subjects showed a similar pattern but significant deficits only on functions. We suggest that the disproportionate deficit on functions reflects a greater cognitive complexity of functions than other semantic relations that renders them more vulnerable either to disrupted processing or to structural degradation of the network of associations among semantic concepts.
Johnson
M K
MK
Department of Psychology, Princeton University, New Jersey 08544, USA.
Hermann
A M
AM
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D003210:Concept Formation; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D010153:Paired-Associate Learning; D011578:Psycholinguistics; D012660:Semantics