Amyloid plaques appear in the brain years before the symptoms of Alzheimer's manifest themselves, research has indicated.
Through the use of two brain imaging techniques, researchers identified apparently healthy older people who had deposits of amyloid plaques in the brain.
The study, published in the Annals of Neurology, indicated that the technique could be used to detect which older people would benefit from early Alzheimer's therapies.
Keith Johnson, from Massachusetts General Hospital, said: "We see that when amyloid deposits are present, even in cognitively normal individuals, the degenerative changes of Alzheimer's are underway. Long-term studies to track these changes and observe how they evolve are ongoing."
In other research news, a long-term memory study published in journal Nature could lead to new treatments for Alzheimer's disease.
Scientists found that the long-lasting increase of signals across brain cell connections is central to the individual's ability to learn and remember over time.