New guidelines for identifying Alzheimer's diseae

By MONIFA THOMAS Health Reporter Chicago Sun Times

Medical experts have issued new guidelines for diagnosing Alzheimer’s disease that, for the first time, attempt to identify the hallmarks of the disease before symptoms occur.

The original guidelines, published in 1984, dealt only with diagnosing Alzheimer’s once a person started showing signs of dementia.

Since then, new discoveries have shown the disease can cause changes in the brain a decade or more before symptoms appear.

The new guidelines — being published online today by the National Institute on Aging and the Chicago-based Alzheimer’s Association — are the first to include the use of brain imaging and measurement of certain proteins in the blood and spinal fluid to spot changes that could be due to Alzheimer’s.

More people will likely be diagnosed with Alzheimer’s — or told they are on the road to developing it — as a result of the recommendations. An estimated 5.4 million Americans have the disease now.

There are no approved treatments to slow or stop the progression of Alzheimer’s. But establishing standards for detecting it earlier will allow scientists to test potential treatments that eventually could be prescribed to people at risk, experts say.

“We believe that it’s critically important when we have more effective drugs to intervene as early as possible,” said guidelines co-author Dr. Reisa A. Sperling, of Brigham and Women’s Hospital in Boston. “The whole goal of the field is to begin to find ways to identify people earlier so that when new treatments are available, we can use them.”

For now, the guidelines won’t have much impact on how primary-care doctors and geriatricians evaluate patients with suspected Alzheimer’s, since new tests to identify the pre-symptomatic stages of the disease are to be used primarily in a research setting, Sperling said.

The guidelines describe Alzheimer’s as a continuum of three stages: preclinical disease, mild cognitive impairment and Alzheimer’s dementia.

In the preclinical stage, changes in the brain can be present but there are no obvious signs of dementia. Mild cognitive impairment occurs when progressive declines in memory and mental ability are noticeable but not severe enough to interfere with daily life.

Tests to identify both of these stages shouldn’t be used outside of clinical trials and research institutions because “there’s an enormous amount we still have to learn about them,” said guidelines co-author Marilyn Albert, of Johns Hopkins University School of Medicine.

Not everyone with preclinical disease or mild cognitive impairment goes on to develop Alzheimer’s dementia, Albert and Sperling noted.

The recommendations for diagnosing the third and final stage — Alzheimer’s dementia — were also revised to reflect that other aspects of cognition outside of memory loss, such as trouble recalling words and impaired reasoning and judgment, may be the first and most dominant sign of dementia.

The guidelines, which have been in the works since 2009, are being published online in Alzheimers & Dementia: The Journal of the Alzheimer’s Association. A preliminary version was released last year at an Alzheimer’s conference in Hawaii.