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The aim of this study is to explore the pattern of change in multiple measures of cognitive abilities in a sample of oldest-old adults, comparing two different time metrics (chronological age and time to death) and therefore examining both underlying conceptual assumptions (age-related change and terminal decline). Moreover, the association with individual characteristics as sex, education, and dementia diagnosis was also examined. Measures of cognitive status (Mini-Mental State Examination and the Swedish Clock Test) and tests of crystallized (knowledge and synonyms), memory (verbal memory, nonverbal long-term memory, recognition and correspondence, and short-term memory), and visuospatial ability were included. The sample consisted of 671 older Swedish adult participants of the OCTO Twin Study. Linear mixed models with random coefficients were used to analyse change patterns and BIC indexes were used to compare models. Results showed that the time to death model was the best option in analyses of change in all the cognitive measures considered (except for the Information Test). A significant cognitive decline over time was found for all variables. Individuals diagnosed with dementia had lower scores at the study entrance and a faster decline. More educated individuals performed better in all the measures of cognition at study entry than those with poorer education, but no differences were found in the rate of change. Differences were found in age, sex, or time to death at baseline across the different measures. These results support the terminal decline hypothesis when compared to models assuming that cognitive changes are driven by normative aging processes.

Abstract. We investigated education and occupational influences as markers of cognitive reserve in relation to cognitive performance and decline on multiple fluid and crystallized abilities in preclinical dementia. From the total sample of 702 participants stemming from the OCTO-Twin Study (Sweden), aged 80+ at baseline in 1992–1993, only those who developed dementia during the study period (N = 127) were included in these analyses. Random effects models were used to examine the level of performance at the time of dementia diagnosis and the rates of decline prior to diagnosis. The results demonstrated that both fluid and crystallized abilities decline in preclinical stages, and that education and occupational class have independent moderating roles on the cognitive performance at the time of diagnosis, but not on the rates of decline.

This study examined children's recognition memory for descriptions of maladjusted behaviors displayed by hypothetical peers. 144 first-, third-, fifth-, and seventh-grade children (mean ages 6.4, 8.4, 10.5, and 12.5 years, respectively) listened to descriptions of hypothetical aggressive, withdrawn, and nonmaladjusted peers, following which they were asked to identify these descriptions from among a second list of descriptions. The children were also asked about the desirability of these hypothetical peers as friends. Whereas children accurately identified the aggressive and nonmaladjusted descriptors at all grade levels, only at grades 5 and 7 were they equally accurate for withdrawal descriptors. Across grade, they also showed an increasing tendency to identify erroneously novel withdrawal and aggression items, but not nonmaladjusted items, as previously displayed by the hypothetical peer. Finally, whereas the aggressive character was low in likability at all grades, the withdrawn character was viewed as increasingly less likable as grade increased. The relevance of these findings to children's peer assessments of aggression and withdrawal is discussed.