Tracking cognitive functioning over time: ten-year longitudinal data from a community-based study

Over 10 years, a community-based sample age 65> or = years, with a starting cohort size of 1,206, was assessed biennially with the Mini-Mental State Exam; the Consortium to Establish a Registry for Alzheimer's Disease battery; Immediate and Delayed Recall of a Story; Verbal Fluency for P and S, Fruits and Animals; Clock Drawing; Temporal Orientation; and Trail Making tests. We report distributions of scores over time, at each wave, in (a) all individuals who were assessed at that wave, whether or not they participated in all waves, and (b) the Survivor subgroup of 425 participants who completed all tests at all 5 waves. Scores and factor structures remained remarkably stable over the study period. The most marked decline over time was seen on the Trail Making tests. As the survivors are de facto a largely healthy and motivated group, their data can be considered population-based healthy norms and may serve as a reference for other studies conducting repeated evaluations using the same tests.