Cognitive changes in young-old adults: effect of family history of dementia.

Cognitive performance of 40 first-degree relatives of patients with probable Alzheimer disease was compared to that of 24 matched controls without a family history of dementia. Across a test-retest interval ranging from 1 to 6 years, relatives more often showed evidence of cognitive decline, and in multivariate analyses of memory and intelligence measures, relatives of patients with early-onset dementia (< 67 years) showed greater decline than controls or relatives of patients with late-onset dementia. All changes observed to date are in the subclinical range, and further follow-up will be needed to determine the reliability of change trajectories. However, the findings suggest that family history of dementia may be worthy of monitoring in research on normal cognitive aging.