Broader Definition of the Disease Could Help Doctors with Early Diagnosis and Intervention In April of this year, the National Institutes of Health and the Alzheimer’s Association announced significant changes in the clinical diagnostic criteria for Alzheimer’s disease dementia. These revisions—the first in 27 years—are intended to help diagnose patients in the very early stages of the disease, allowing doctors to prescribe medication when it is most effective; that is, before a patient’s memory becomes compromised. The new guidelines recognize two early stages of the disease: preclinical Alzheimer's, in which biochemical and physiological changes caused by the disease have begun; and mild cognitive impairment, a stage marked by memory problems severe enough to be noticed and measured, but not severe enough to compromise a person’s independence. The new guidelines also reflect the increased knowledge scientists have about Alzheimer’s, including a better understanding of the biological changes that occur and the development of new tools that allow early diagnosis. William H. Thies, chief scientific and medical officer of the Alzheimer’s Association, explains, “If we start 10 years earlier and could push off the appearance of dementia by, say, five years … that could cut the number of demented people in the U.S. by half” ( Los Angeles Times , April 25, 2011). For more information about the updated guidelines, as well as a list of journal articles and answers to frequently asked questions for clinicians, visit the National Institute on Aging Web site at http://www.nia.nih.gov/Alzheimers/Resources/diagnosticguidelines.htm .