Doctors may be able to identify people in the earliest stages of Alzheimer’s even if they have not yet displayed any symptoms, a new study suggests.

More than 300 people in their 70s and 80s had their brains scanned as part of a study published online in the journal Neurology.

The scans showed that the brains of a third of participants had significantly high levels of protein deposits that can be linked to Alzheimer’s, and that these people also had abnormal levels of metabolic brain chemicals associated with mental decline.

Scientists have said that, while more research is needed, people with these high levels of protein deposits in their brain could be in the earliest stages of Alzheimer’s. The ability to diagnose the disease at a very early stage would allow patients to receive the most appropriate advice and treatment from the start.

Lead researcher Dr Kejal Kantarci, from the Mayo Clinic in Rochester, US, said: ‘More research is needed that follows people over a period of years to determine which of these individuals will actually develop the disease and what the relationship is between the amyloid deposits and the metabolites.’