Harvard Mental Health Letter

New diagnostic criteria for Alzheimer's disease

The National Institute on Aging and the Alzheimer's Association has published new guidelines for the diagnosis of Alzheimer's disease. This is the first update since the original guidelines were created in 1984. The guidelines include several significant changes. First, they describe three disease stages: asymptomatic (preclinical), thinking difficulties (mild cognitive impairment), and dementia (Alzheimer's). This is the first formal recognition of what research has suggested for several years now — that Alzheimer's disease evolves gradually over many years and that physiological changes in the brain occur a decade or more before noticeable symptoms such as memory loss or behavioral changes. Second, the guidelines propose — for research purposes only — using biomarker tests in conjunction with clinical assessments to determine whether someone might be at an early stage of Alzheimer's. The biomarkers are still being tested, however, and are not meant for routine use in a clinical setting. Finally, the guidelines emphasize that although Alzheimer's usually involves memory loss, in some cases it will cause other symptoms first — such as difficulty in finding the right words for something or problems seeing the "big picture" in a situation. Investigators, clinicians, and policy makers are hoping the guidelines will help accelerate research on ways to prevent or at least slow the progression of Alzheimer's. 
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