Heterogeneity of cognitive aging in Brazilian normal elderls

With aging, several cognitive skills inevitably decline. However, cognitive losses do not occur homogenously in all elderly people, differing in number and severity of affected cognitive functions. These differences could be exacerbated by socioeconomic differences in a developing country like Brazil. OBJECTIVES: to characterize the cognitive functioning of healthy elderly subjects whose socioeconomic conditions differ to those of other studies. METHODS: 60 elderly subjects with a mean age of 68 years, 43 women and 17 men, and mean schooling of 7.1 years, were studied. The cognitive function of this group was assessed using the following neuropsychological tests: Mattis Dementia Rating Scale (MDRS), Stroop Test, Verbal Fluency, Wisconsin Card Sorting Test (WCST), Rey Complex Figure, Vocabulary – Wais – III, Logical Memory (WMS-R), Visual Reproduction (WMS-R), and Rey Auditory-Verbal Learning Test (RAVLT). The neuropsychological data were submitted to Multivariate cluster analysis using SAS - Proc Cluster software and the complete binding hierarchical method. RESULTS: Variability was found allowing classification of the studied group into 4 clusters of individuals who had above-average (C1), average (C3 and C4) and below average (C2) performance. Schooling determined the results obtained, with less educated subjects showing poorer performance than higher-educated subjects. CONCLUSIONS: Significant differences in the process of cognitive aging were detected on neuropsychological tests in this group of healthy elderly from the developing country of Brazil, where socioeconomic differences may exacerbate cognitive differences among older adults.