A new test has been developed to predict an individual's risk of developing dementia over the six years following the test.
Using medical history, a physical examination and cognitive testing, a person's risk can be predicted with 87 per cent accuracy.
A more comprehensive test which has also been developed has an 88 per cent rate of accuracy.
The tests involve assessing cognitive ability in everyday tasks such as doing up a button, taking into account medical background such as history of bypass surgery, consumption of alcohol and body mass index.
Researchers formulated the tests using more than 3,000 people from all physical and mental demographics, who were monitored over six years.
Dr Barnes, a professor of psychiatry to the University of California, said: "There are tests that accurately predict an individual's chances of developing cardiovascular disease and other maladies, but, until now, no one has developed similar scales for dementia."
The tests are yet to be carried out on a range of ethnic groups, which is a requirement for them to become standard clinical tools.
Dr Barnes said: "We certainly plan to look at other groups to see if these results are valid across a variety of populations."