The risk of memory loss in healthy, older adults has been predicted in a new study by scientists at Wayne State University.
The combined results of a genetic blood test and a five-minute functional MRI successfully classified more than three-quarters of healthy older adults, many of whom were destined to develop cognitive decline within 18 months of testing.
The results have strong implications for determining who is most likely to benefit from preventive Alzheimer's disease treatments.
John Woodard and his colleagues performed five tests on 78 healthy elders: a structural MRI (sMRI) that measures the size of the hippocampal region of the brain; a functional MRI (fMRI) that shows how the brain is activated during mental tasks; a blood test that identifies the APOE e4 allele (a known genetic marker for Alzheimer's disease); and two standard neuropsychological tests that measure mood and ability.
The most effective combination of tests to predict near-term cognitive decline was the fMRI and the APOE e4 test.
The APOE e4 allele alone correctly classified 61.5 percent of participants, but the combination of the e4 allele and low activity on the fMRI test correctly classified 78.9 percent of participants, including 35 percent who showed significant cognitive decline 18 months post-testing.
Woodard team also found that persons with larger hippocampal volume, greater functional brain activity and no APOE e4 allele were less likely to demonstrate cognitive decline over the following 18 months.
The finding has been published in the Journal of Alzheimer's Disease.