Cognitive stability over 2 years in a rural elderly population: the MoVIES project.

In an ongoing prospective community study, a random sample of rural elderly persons was screened with cognitive tests (including the CERAD neuropsychological battery) at study entry and an average of 2 years later. We examined 1,017 subjects, nondemented at study entry, at both waves, with the Mini-Mental State Exam, Story Recall, Word List Recall and Recognition, Boston Naming Test, Verbal Fluency, Praxis, Clock Drawing, and Trailmaking. Overall, the cognitive performance was stable, with either no mean change or a small mean decline over 2 years; however, standard deviations were relatively large, implying individual variation of questionable clinical significance. These data provide a set of population-based longitudinal cognitive norms and have implications for dementia screening.