Semantic relations in elderly adults, Mild Cognitive Impairment and Alzheimer’s disease

Abstract

The decreased performance of Alzheimer’s Disease (AD) patients in semantic tasks is related to the progressive loss of the semantic attributes underlying category representation. The present study examined the extent to which semantic tasks focused on the ‘living beings’ category are affected as a function of the type of semantic relation between the nodes and the degree of cognitive impairment associated to AD. One hundred and eight volunteer participants from the Autonomous City of Buenos Aires, Argentina (Age M = 71 years old, SD = 6, Education M = 10 years old, SD = 5) completed a true-false sentence verification task. The task evaluated three types of semantic relation: taxonomic, part-whole and evaluative. The sample was divided into four groups, based on their cognitive performance: controls (n = 27), mild cognitive impairment or MCI (n = 50), mild AD (n = 36) and moderate AD (n = 14). The results showed decreased performance in false statements and greater impairment of the part-whole relationship in the groups with AD as compared to the rest. A stepwise trend across groups was also observed, with the control group showing the best performance, followed by the MCI and mild AD groups, followed by the moderate AD group, although not all of these differences reached significant differences. Results are interpreted in light of their potential impact for clinical work.