"The definition of Alzheimers disease just got wider and deeper but the expansion wont change how the vast majority of people are diagnosed. It also doesnt change the very limited treatment choices. But the new criteria which were developed by the National Institute on Aging and the Alzheimers Association are almost guaranteed to prompt confusion even in people who are thinking quite clearly. For research theres a lot of value. For everyday clinical use very very little. David Knopman a professor of neurology at the Mayo Clinic The guidelines say for instance that newly developed biomarker tests such as assays for proteins in spinal fluid and some specialized brain scans can be used for early diagnosis of Alzheimers. But the guidelines say the tests are to be used only for research and not for diagnosing Alzheimers in the general public. The distinction is nothing to worry about for patients and their families. You dont need a biomarker test for everyday clinical practice says David Knopman httpmayoresearch.mayo.edumayoresearchstaffknopman_d.cfm a professor of neurology at the Mayo Clinic who was cochairman of the group that revised the dementia diagnosis. The existing tests for Alzheimers are adequate he says. And those biomarkers Its in the fine print but it definitely says in multiple places that the biomarkers are for research purposes. Why Well the biomarker tests and PET scans httparchneur.amaassn.orgcgicontentfull arent yet accurate enough to reliably diagnose Alzheimers and havent been approved by the Food and Drug Administration. And its also because there are no treatments that can prevent slow or stop early signs of Alzheimers. For research theres a lot of value Knopman says. For everyday clinical use very very little. About  million Americans have Alzheimers. The hallmark signs are problems with thinking learning and memory. The current definition created in  describes Alzheimers that way. But over the past few years theres been solid evidence that Alzheimers starts damaging the brain years before a person starts having noticeable problems thinking. Scientists have been putting a lot of effort into trying to identify what starts the disease process but have so far come up empty. The new definitions which were just published online http by the journal Alzheimers  Dementia acknowledge this dimly understood early phase of Alzheimers. Now there are two new predementia phases mild cognitive impairment and preclinical Alzheimers. In mild cognitive impairment a persons changes in thinking are noticeable to himself friends or family. They would show up on tests of memory and recall but dont interfere with everyday activities. Alzheimers is just one possible cause. Because there are no treatments http to prevent or stop Alzheimers many people may not consider this diagnosis a blessing. The second new phase preclinical Alzheimers is much squishier. Theres no list of symptoms that a doctor can whip out to say youve got it. Rather the goal in creating this category is to see if scientists can define when the disease starts and track it through biomarker tests brain imaging or other yettobeinvented tests. If that happens it might someday lead to ways to prevent Alzheimers. But for now this category is useful only to researchers. The goal in all this according to the Alzheimers Association is to increase opportunities for earlier diagnosis http and treatment. The problem is that there arent yet any reliable tools for earlier diagnosis and treatment. The new criteria are really a call for more research  and the money to fund it. That would be good for the Alzheimers Association https and the National Institute on Aging http which sponsored the work on the new criteria. And it does leave one wondering if a lot more worry will be generated by the notion of preclinical Alzheimers when science and medicine cant offer anything to ease those fears."