Investigators working to detect subtle changes in cognitive ability form part of the ongoing effort to develop ways of identifying people who will go on to develop AD in the future. In the September Archives of General Psychiatry, researchers led by Mary Ganguli at the University of Pittsburgh School of Medicine in Pennsylvania report that they have noticed a decline in executive ability (in addition to the more expected decline in memory loss) in the years prior to diagnosed AD.
The study is the fourth published since last year that assessed cognitive function at multiple time points during the preclinical phase of AD. Measuring changes in a battery of 15 cognitive tests at 3.5 and 1.5 years prior to diagnosis, the researchers found a subtle but broad decline across all tested cognitive domains. This adds to emerging evidence that cognitive performance gradually declines from about six to one year prior to diagnosed AD, followed by a steeper and more alarming loss that prompts patients to visit a neurologist (Small et al., 2000).
The current study contains analysis of 551 elderly people from the 10-year prospective Monongahela Valley Independent Elders Survey (MoVies), 68 of whom developed symptomatic AD.
In a commentary in the same issue, Brent Small of the University of Florida notes that longitudinal methods to studying cognitive decline can contribute to the development of a 3hybrid prediction model2 that combines biological, brain imaging, and cognitive markers to identify people at risk for AD.—Gabrielle Strobel
No Available References
- Small BJ, Fratiglioni L, Viitanen M, Winblad B, Bäckman L. The course of cognitive impairment in preclinical Alzheimer disease: three- and 6-year follow-up of a population-based sample. Arch Neurol. 2000 Jun;57(6):839-44. PubMed.
- Chen P, Ratcliff G, Belle SH, Cauley JA, Dekosky ST, Ganguli M. Patterns of cognitive decline in presymptomatic Alzheimer disease: a prospective community study. Arch Gen Psychiatry. 2001 Sep;58(9):853-8. PubMed.
- Small BJ, Fratiglioni L, Bäckman L. Canaries in a coal mine: cognitive markers of preclinical Alzheimer disease. Arch Gen Psychiatry. 2001 Sep;58(9):859-60. PubMed.