LONDON, March 6 (Xinhua) -- New research has shown that the onset of Alzheimer's can be detected several years before the symptoms manifest themselves, science news website Alpha Galileo reported on Tuesday.

    A new doctoral thesis by Johanna Lind of the Karolinska Institute in Sweden shows that genetic mapping and brain imagery can be used to identify people who will develop dementia even before any clinical symptoms appear.

    The method is based on the well-established fact that the apoE protein affects the risk of developing Alzheimer's.

    Roughly one person in five carries a genetically determined variant of apoE, a lipid-transporting protein important in the repair of cerebral neurons, which is associated with an increased risk of Alzheimer's.

    According to the report, Lind was able to show in her study that some people in this risk group had reduced parietal lobe activity and that these same people went on to suffer memory deterioration two to three years later.

    "This is a crucial step towards the better diagnosis of Alzheimer's. It's surprisingly difficult to diagnose Alzheimer's with any certainty, but things are made easier if you know who runs the greatest risk. If genetic mapping, magnetic resonance imaging (MRI) and cognitive tests all suggest the onset of Alzheimer's, it might be an idea to start a course of treatment in good time," the researcher was quoted as saying.

    Dementia involves a serious deterioration of mental function caused by some kind of dementia disease of the brain, of which Alzheimer's is the most common.

    Dementia diseases are generally discovered when the memory has already started to deteriorate. Although there is currently no cure for Alzheimer's, it is possible to inhibit its development if the treatment is given early enough.