Semantic anomaly judgement in individuals with probable Alzheimer's disease

BACKGROUND: Research has shown that individuals with probable Alzheimer's disease (PrAD) show impaired semantic knowledge of nouns. More specifically, while they demonstrate preserved superordinate category information, information regarding specific semantic attributes associated with subordinates appears to be disrupted. Results of some recent studies suggest that PrAD participants may also be impaired in processing semantic information associated with verbs. AIMS: Provided that a parallel exists between PrAD participants' noun and verb impairment, it is plausible that the semantic deficits observed in the breakdown of their noun lexicon may also exist in their knowledge of verb-related information. This experiment examined PrAD participants' knowledge of the semantic restrictions associated with the complements of verbs. METHODS #ENTITYSTARTX00026; PROCEDURES: Fourteen PrAD participants were asked to judge the semantic plausibility of 44 auditorily presented sentences. To examine their knowledge of the selection restriction of verbs, each verb was paired with two plausible complements that fully met the restriction, an implausible complement that violated the specific attributes required but belonged to the correct semantic category, and an implausible complement that violated the semantic category requirement. OUTCOMES #ENTITYSTARTX00026; RESULTS: Results showed that PrAD participants' errors were primarily on anomalous sentences that contained implausible complements that belonged to the correct semantic category. CONCLUSIONS: This finding confirms our hypothesis and suggests that a parallel pattern exists in PrAD participants' breakdown in noun and verb knowledge.