Changes in cognitive functioning from 75 to 80 years of age: a 5-year follow-up in two Nordic localities.

The purpose of the study was to analyze changes and stability in cognitive functions among older persons aged from 75 to 80 years, as well as differences in this development between two Nordic localities. The number of subjects taking part in the follow-up phase was 188 in Jyväskylä, Finland, and 184 in Göteborg, Sweden. Cognitive functions were assessed using conventional memory tests (Digit Span Forward and Backward for assessing primary working memory; Visual Reproduction for visual memory) and intelligence tests (Digit Symbol for assessing psychomotor speed; Word Fluency for verbal ability; Raven's Matrices for non-verbal reasoning). With few exceptions, the mean test scores declined significantly among the retested men and women in both localities. Analyses showed that generally over half of the subjects maintained their level of performance over the 5-year period, while a part of the deteriorating minority had a steep decline. There were significant differences in the test performance between the localities both at the baseline and follow-up assessments, but few differences between women and men. On the whole, however, the groups of older women and men from the two Nordic localities had a similar pattern of cognitive development from 75 to 80 years of age.