Lexical relations in Spanish-Speaking older adults with Alzheimer's disease: An approach to semantic memory

Abstract

Changes associated with aging intensify when older adults are diagnosed with cognitive impairment. In order to describe such changes in semantic memory, this study compared the lexical relations produced by Mexican older adults diagnosed with Alzheimer's disease (AD) with those with typical aging (TA) in a free word association task. Participants were 24 older adults, 12 with AD and 12 with TA; all were right-handed monolingual Spanish speakers, 55 years of age or older, and with an educational level of at least one year. Older adults with AD were diagnosed according to clinical criteria. Both groups had similar demographic characteristics: sex, age, and years of education. The free word association task used 234 high-frequency concrete nouns of early acquisition. Two codings were performed: one based on classification of syntagmatic and paradigmatic relations, and the other on semantic association, wide association, and association by signifiers. Our results showed differences in the type of lexical relations generated by older adults with AD as compared with those with TA; semantic memory in the AD group presented alterations, but various lexical relations were preserved, at least in the moderate stage of the disease. We identified how words are connected and the state of semantic memory in older adults with AD.