In what can be termed a clinical revolution, a simple blood test to detect the onset of Alzheimer's disease, long before its victims are robbed of their memory, has been created.

An international team of scientists has found a type of 'cellular chatter' that reveals early evidence of the disease, providing a chance to interfere in its progress, according to a study published in the Nature Medicine journal.

"Just as a psychiatrist can conclude a lot of things by listening to the words of a patient, so by listening to different proteins, we are measuring what is going wrong in the cells. Our data indicates that blood contains a highly-specific biological signature that can characterise Alzheimer's disease years before a clinical diagnosis can be made," lead researcher Dr Tony Wyss-Coray of Stanford University stated in the article.

The scientists came to the conclusion after studying data obtained from more than 250 blood samples that had been stored for years in laboratories in the United States and Europe -- some were from healthy people while others from Alzheimer's patients.

When the test was used on blood from healthy people and from people with Alzheimer's, it predicted the disease with 90 per cent accuracy. Then they looked at whether it could pick up Alzheimer's before the symptoms appeared � they used samples taken from people who had been suffering from mild memory loss at the time the blood was taken.

Two to six years after the samples were taken, some patients had deteriorated to such a degree that they had been diagnosed with Alzheimer's while others were still healthy.

Again, the test proved approximately 90 per cent accurate, distinguishing between those who had been simply forgetful and those who went on to develop Alzheimer's, according to their findings.