Disease develops years before symptoms show.
New guidelines for diagnosing Alzheimer's disease set forth methods for identifying the disease before it progresses to full-blown dementia, and for the first time include lab and brain-imaging tests that can help identify Alzheimer's as the likely cause of a person's mental decline.
The guidelines, revised for the first time in 27 years, reflect a firm consensus among Alzheimer's researchers that the disease begins to attack the intricate structures of the brain 10 years or more before the disabling mental problems appear. Therefore, to be effective, drug or other therapies will have to begin work early in that process.
So far, though, there are no therapies that alter the course of Alzheimer's disease. And in a media briefing, authors of the new diagnosis guidelines emphasized that while testing for Alzheimer's pathology in the brain may one day be used to identify the disease at much earlier stages, today the tests are primarily a research tool. They are not ready for routine use in doctors' offices.
Even so, doctors hope the new diagnostic criteria encourage people with worrisome memory problems to seek help. There's a lot patients and their families can do to minimize the impact of Alzheimer's, from structuring the patient's environment to optimizing medical care, activities, exercise and diet.
New tests outlined in the guidelines involve looking at the brain with imaging technologies and examining the fluid obtained by a spinal tap. The imaging studies can reveal so-called plaques made up of a protein called amyloid, a defining feature of Alzheimer's. They also can indicate characteristic patterns of shrinkage or reduced metabolic activity in the brain. The cerebrospinal fluid tests look for levels of amyloid as well as of another protein, tau, which makes up the twisted strands or "tangles" that, like plaques, are signature brain pathology in Alzheimer's.
Weaknesses of the tests
Research studies have demonstrated that all these tests can help identify Alzheimer's as the cause of a patient's dementia, and can help predict which patients with milder symptoms will go on to develop dementia. But the tests aren't conclusive in themselves. They aren't standardized so that a certain result means the same thing in every medical center. And there's no clear cutoff separating normal findings from those indicating a problem.
Original article by: Katharine Greider from AARP Bulletin