Simple blood test may predict memory decline risk

Washington: Scientists have found a blood protein which causes significant mental decline in elderly people — a risk which they claim could be detected early through a simple blood test.

Researchers at the University of California found that elderly people who have low blood levels of beta-amyloid 42 protein are more prone to cognitive decline within nine years.

But, Dr Kristine Yaffe, who led the study, said a simple blood test to know beta-amyloid 42 levels could, however, help detect the risk and take appropriate medication, LiveScience reported.

For their study, Dr Yaffe and colleagues looked at 997 older adults with the average age of 74 years who participated in a health study.

Interestingly, among the participants found to have low beta-amyloid 42, cognitive decline was less prominent in those with higher literacy levels, more education, or who lacked a specific gene, called APOE e4 — which is linked to a greater risk of dementia. The researchers call this group of factors "cognitive reserve."

"We show that a blood test for beta-amyloid 42 might be a good way to predict those at risk for cognitive decline," said Yaffe.

"Also, for the first time, we show that cognitive reserve — a general level of resiliency in the brain — might modify that risk in the elderly."

Yaffe said that currently,  "there is no reliable method of predicting ahead of time who will experience cognitive decline and go on to develop dementia. A blood test would be a huge step forward."

She added that there is currently an experimental test that looks for beta-amyloid in cerebral spinal fluid, "but a blood test would be far easier, less invasive, and less expensive than the lumbar puncture required to obtain spinal fluid."

Low levels of beta-amyloid 42 in the blood and spinal fluid, she said, point to high levels in the brain, "which acts as a sink for beta- amyloid in Alzheimer`s disease".

However, she adds that "we might actually be able to modify the risk of dementia before it becomes manifest."

"If you find out that you have low beta-amyloid 42, but you haven`t yet experienced any obvious cognitive decline, you might try and increase your cognitive reserve by staying mentally active — reading, taking classes — and thereby mitigate or at least delay the damage."

The research is published in the Journal of the American Medical Association.