Effects of sequential neuropsychological testing of an elderly community-based sample.

The magnitude and importance of changes in scores of neuropsychological tests on retest in the elderly, especially over long time periods, is not well established. Three neuropsychological tests and one mental status test were initially administered to screen for potential dementia and were readministered to 380 of the surviving individuals 2.4 years later who either failed the screening examination or were an age matched control. Of the 380 women and men aged 65 and older, 56 were diagnosed as having Alzheimer disease (AD), 82 as at risk for developing AD, and 242 as having normal cognition. The present report focuses on changes in test scores between the two visits. In the normal and at risk groups, significant improvements were seen on retest of the Visual Reproduction Test (VRT), the Trails B test, and the Mini-Mental Status examination; verbal fluency decreased, and savings score of the VRT showed small variations. On most tests, scores of the AD group decreased. Practice effects, biases, and other variables may have played a role in the improvements seen in those labeled normal and at risk. If these results are confirmed, savings score of the VRT (which remained stable over time in normals and individuals at risk and decreased in patients with dementia) and verbal fluency (which decreased in all groups) may be better measures of true cognitive performance than the other tests that we evaluated.