Criteria revised for Alzheimer's diagnosis

The criteria for diagnosing Alzheimer's disease have been revised to reflect newer scientific knowledge, the first such change in more than a quarter-century.

The new criteria call on doctors to recognize the disease that evolves over many years, possibly decades, long before symptoms such as dementia become apparent.

The National Institute on Aging, the major government research center that conducts and funds Alzheimer's studies, and the Alzheimer's Association, the nation's leading advocacy organization for patients and caregivers, announced the new criteria Monday.

"We used to make a diagnosis only when people had dementia," said Dr. Reisa Sperling, a member of the team that wrote the new guidelines. "We normally would say, 'You have a little memory trouble come back in one or two years and we'll see what's going on.' "

Now, leaders in the Alzheimer's-care community underscore that Alzheimer's is a progressive disorder -- a contiuum -- with three distinct stages. Moreover, the disease begins years before the dramatic symptoms of dementia ensue. The last diagnostic guidelines, released in 1984, recognized only one stage -- dementia.

The guidelines also expand the concept of Alzheimer's dementia beyond memory loss, noting that a decline in other aspects of cognition, such as word-finding, vision or spatial issues, and impaired reasoning and judgment may be the first symptoms for some patients.

However, altering the diagnostic criteria -- especially diagnosing people sooner -- could change the number of patients with Alzheimer's, possibly doubling the population of those affected, experts estimated Monday.

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But while it's possible for the population to double, the team responsible for the recommendations was not prepared to say with certainty that the number of people with the mind-robbing condition would jump from 5.4 million to 10.8 million overnight."I think the idea is to wait to see what happens," Sperling said.

Changing the diagnostic criteria also does not offer solutions such as drug treatment because drugs currently approved are designed to address later-stage symptoms and do not thwart the underlying biological mechanisms of the disease.

However, a new generation of medications aimed at a brain-destroying protein known as an amyloid deposit, which irrevocably damages the brain, are expected to be on the market within two years, doctors said.

"Historically, we have been diagnosing Alzheimer's disease only when patients have reached the clinical stage of dementia," said Dr. Marc Gordon, a neurologist and Alzheimer's researcher at the Feinstein Institute for Medical Research in Manhasset.

New diagnostic criteria for Alzheimer's are based on a series of new studies also reported yesterdayMonday. "We believe that the publication of these articles is a major milestone for the field," said Dr. William Thies, chief medical and scientific officer at the Alzheimer's Association. "Our vision is that this process will result in improved diagnosis and treatment of Alzheimer's."