Researchers have developed a test that identifies changes in blood plasma to provide a step towards letting people know their chances of developing Alzheimer's disease.

Scientists at Stanford University School of Medicine have found that the test could predict the onset of the condition up to six years before the patient developed symptoms, the institution has announced.

The method identifies changes in proteins within blood plasma that cells use to send messages to each other and the team found a connection between shifts in the dialogue between such cells and alterations in the brain associated with the onset of Alzheimer's.

Tony Wyss-Coray, senior author of the study and associate professor of neurology and neurological sciences, commented that by 'listening' to the different proteins, the team was able to measure whether something is going awry in the cells.

"It's not that the cells are using new words when something goes wrong. It's just that some words are much stronger and some are much weaker, the chatter has a different tone," he explains.

Alzheimer Scotland reports that there are an estimated 33,550 people in the country who currently suffer from the condition.