Terminal change in cognitive function: an updated review of longitudinal studies.

We provide an update to Siegler's (1975) review of the terminal change literature. Articles identified through MEDLINE, CANCERLIT, PUBMED, and PSYCINFO from 1975 to 2000 were examined. Lower levels of cognitive function are related to increased risk of mortality; however, the relationship between rate of cognitive change and mortality is less clear. Although there has been an increase in the number of studies since our last review, prior studies have been limited by a lack of medical data, consideration of dementia, small sample sizes, and poor cognitive measures. The emphasis on Alzheimer's disease and the growth of epidemiology of aging in the past 25 years have provided well-characterized population studies with serial cognitive measures that provide an opportunity to test the theory of terminal change.