Alzheimer's disease guidelines are updated after 27 years

Nearly three decades since the first diagnostic guidelines for Alzheimer's disease were released, medical experts have issued a new set of criteria to identify the neurologic disorder.

The recommendations focus on early detection before the onset of dementia due to Alzheimer's disease. They also expand the disease symptoms beyond memory impairment to include spatial cognition problems, impaired reasoning and difficulty expressing oneself with words.

The short-term impact on primary care physicians is expected to be relatively modest, said Bill Thies, PhD, chief medical and scientific officer of the Alzheimer's Assn., the largest private, nonprofit funder of Alzheimer's research.

But he said he hopes the changes will help encourage physicians to monitor patients' cognitive function in an effort to identify people with mild symptoms of the condition.

"The new criteria give us powerful tools to accelerate our knowledge in the fight against Alzheimer's disease. They give us guidelines for getting a more accurate assessment of Alzheimer's prevalence. ... And they give us a basis for creating the next generation of Alzheimer's treatments," Thies said.

The association and the National Institute on Aging organized three expert work groups to review advancements in Alzheimer's research and determine whether diagnostic procedures should be changed. The new criteria were published online April 19 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.

They update guidelines issued in 1984. Since then, researchers have learned that there are genetic risks of Alzheimer's and that the disease process can start more than a decade before symptoms appear.

"If you're seeing someone over a period of years as a primary care physician, you have one of the best opportunities to [identify] when they have mild symptoms" of the disease, Thies said.

Early detection enables patients to receive medication that could help slow Alzheimer's progression. Current drugs improve symptoms and delay the decline of the disease for some people. But none of the medications modifies the disease process.

People diagnosed early can join clinical trials aimed at developing such disease-modifying drugs. They also can prepare themselves and their families for the progression of the condition.

An estimated 5.4 million Americans have the degenerative disease, according to the Alzheimer's Assn. Less is known about the prevalence of mild cognitive impairment, in which people have mild changes in memory and thinking that can progress to Alzheimer's dementia.

The new guidelines include criteria to diagnose this early phase. Identifying patients who have MCI could more than double the number of people with Alzheimer's, Thies said.

The impact of diagnosing this new stage, along with the nation's growing elderly population, probably will send a surge of dementia patients to physician offices, said Arizona neurologist Marwan Sabbagh, MD.

To ensure that doctors can handle the new demands, he said it is imperative that they understand the diagnostic guidelines and are aware of advances in the Alzheimer's field.

"There's no easy way around this," he said.

The new guidelines detail three phases of Alzheimer's. They are expected to help health professionals identify patients with cognitive impairment who might have gone untreated because their symptoms did not fit existing criteria.

The first phase is preclinical Alzheimer's, in which a patient experiences detrimental neurologic changes before overt symptoms are present. Biomarkers such as neuroimaging would be used to identify such changes and predict a person's risk of developing the disease. The guidelines do not include diagnostic criteria for using these tools. Rather, the work groups are calling for further research into the use of biomarkers and their effectiveness.

Mild cognitive impairment due to Alzheimer's disease is the second phase. In this stage, a person has mild changes in memory and thinking abilities, but he or she is not impaired. Physicians can use tools such as the Free and Cued Selective Reminding Test to help identify patients with MCI. The test asks patients to identify common items on a card and then recall the objects when the card is taken away.

Dementia due to Alzheimer's is the final phase, when memory, thinking and behavioral symptoms impair a person's ability to function in daily life. Criteria for diagnosing this condition include symptoms with a gradual onset over months to years and worsening of cognition. The guidelines remove age restrictions for the onset of the disease.

The recommendations issued in 1984 featured only one category: definite Alzheimer's disease. The criteria for this diagnosis included dementia established by clinical examination, deficits in at least two areas of cognition and onset between age 40 and 90.

Jill Grimes, MD, a family physician in Austin, Texas, said the new guidelines will not change her practice dramatically. But, she said, "I do feel like I can tell [patients] with more confidence that biomarkers are a huge step in the right direction, and that's the area of research we want to be watching."