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Thursday, 6 September, 2001, 00:21 GMT 01:21 UK
Alzheimer's predicted 'years in advance'
The researchers monitored elder people's brain activity
The researchers monitored elder people's brain activity
A test has been developed which could one day tell people if they are likely to develop Alzheimer's disease in later life.

At the moment, this, and other similar conditions, can only be diagnosed when people start showing symptoms, such as memory loss.

But the New Scientist reports on a test being pioneered in the United States which has found key parts of the brain "'move down a gear" years before symptoms appear.

If the test does become widely available, issues would arise about whether people will want to know if they are at risk and how insurance companies might view the results.

Developing ways of detecting and identifying dementia earlier, and even before significant symptoms appear is becoming increasingly important

Richard Harvey,
Alzheimer's Society
But advocates say it would at least allow people to take preventative action, such as taking vitamin E and anti-inflammatory drugs which have been shown to slow the disease down, though it is not certain how much.

UK Alzheimer's experts said new methods of detecting dementia were welcome, but said the US technique was too expensive.


Researchers from the New York University School of Medicine assessed 48 people in their 60s, 70s and 80s.

They were tested on how efficiently their brain worked at the beginning of the study, and again after three years, and compared them to 13 healthy people of the same age.

All were given PET scans (Positron Emission Tomography) which use low-dose radioactivity sugar to measure brain activity to show where glucose is being metabolised in the brain.

They looked at areas known to be involved in memory loss and Alzheimer's.

They found, compared to healthy people, those who had significant memory loss had substantially less glucose in an area called the entorhinal cortex.

The researchers, led by Dr Mony De Leon, say this can predict memory loss up to three years in advance.

In the second tests, 13 did much worse than in the original evaluation, with one being diagnosed as having Alzheimer's Disease, and 12 with "mild cognitive impairment".

Gary Small, a neuroscientist from the University of California in Los Angeles predicts some form of brain scan could eventually be used to routinely check people at risk of problems in advance - maybe decades before any problems became apparent.

He said: "There are always risks for abuse. But there are also tremendous benefits."


PET scans are not suitable for routine screening because they are costly and invasive, so are only useful for people at high risk of Alzheimer's.

But there are moves to make them more widely available.

Richard Granger, a cognitive computer scientist at the University of California, Irvine has led the development of a portable head cap which carries electrodes which can analyse electrical activity in the brain.

The 12 minute test can pick out people who already have Alzheimer's, "mild cognitive impairment" and depression with 98% accuracy

The team are now looking to see if the device can be used to predict who will go on to suffer problems.

Richard Harvey director of research for the Alzheimer's Society, said: "Developing ways of detecting and identifying dementia earlier, and even before significant symptoms appear is becoming increasingly important as we see new treatment and prevention strategies emerging.

"Functional brain imaging using PET is unfortunately a scarce and expensive technique, yet this research shows that we can identify those at the highest risk of Alzheimer's disease.

"We now need more work on cheaper and simpler techniques that can show the same thing, and which could be used for screening tests in the future."

See also:

06 Jun 01 | Health
Vaccine hope for Alzheimer's
24 Apr 01 | Health
10-minute test for Alzheimer's
07 May 01 | Health
Alzheimer's linked to vitamins
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