Mayo Clinic Radio: Redefining Alzheimer’s disease An estimated 5.5 million Americans are living with Alzheimer’s disease, according to the Centers for Disease Control and Prevention. Alzheimer's disease progressively destroys memory and other mental functions. Traditionally, a diagnosis is made by evaluating symptoms and cognitive behavior associated with the disease. But, in April, a team of scientists with the Alzheimer's Association and the National Institute on Aging proposed a new Alzheimer's disease research framework. Under the new framework, the definition of Alzheimer’s disease in living people — for use in research — is not based on cognitive changes and behavioral symptoms. Instead, the disease is diagnosed by its neuropathology. This shifts thinking that symptoms are a consequence of the disease — not the definition of the disease. Scientists hope a change in definition will enable research to better target patients, so clinical trials will be more effective.