A Look at the New Guidelines for Diagnosing Alzheimer's Disease

In April, there was a lot of buzz when the National Institute on Aging (NIA) and the Alzheimer’s Association announced new “Diagnostic Guidelines for Alzheimer’s Disease.”

What do they mean to you?

RICHARD E.POWERS,M.D., chairman of the Alzheimer’s Foundation of America’s Medical Advisory Board, recently interviewed MARIE A.BERNARD,M.D., deputy director of the NIA and one of the experts who helped develop the guidelines, to gain further insight into the new diagnostic criteria.

Question: What is the difference between dementia and Alzheimer’s disease?

Answer: Dementia is the umbrella term for brain disorders that cause a person to lose their ability to function normally in daily life. Alzheimer’s disease is the most common, but there are other dementias, such as vascular, Lewy body, etc. Although we know Alzheimer’s dementia is distinct from these other forms, in the early stages it may be difficult to differentiate among them. Additionally, many older people may have more than one condition, such as Alzheimer’s disease combined with vascular disease and sometimes small strokes.

That is one of the reasons why researchers hope one day to develop an easy-to-administer, reliable and inexpensive biomarker—a test that indicates harmful changes taking place in the brain—that can be used in a doctor’s office. For example, eventually there may be a simple blood test to help diagnose Alzheimer’s disease.

Question: How was dementia diagnosed before these new guidelines and what has changed?

Answer: The new guidelines do not dramatically alter the current process doctors use to diagnose Alzheimer’s disease. Dementia is still diagnosed based on significant and chronic changes in a person’s thinking processes, or as a professional would state, cognition. Healthcare providers speak with the patient and family or caregivers, seeking observations about changes in how the patient thinks, learns and remembers and taking into consideration other potential causes of cognitive decline—for example, medications, malnutrition, dehydration, depression. However, the new guidelines ask doctors to look beyond just memory loss for additional symptoms that may mark onset of the disorder, such as problems with judgment. And the revised guidelines outline ways the healthcare provider should approach evaluating the causes and progression of cognitive decline. For example, healthcare providers are made aware that mild cognitive impairment (MCI) may in many cases progress to Alzheimer’s disease and that memory impairment is not always the first symptom of Alzheimer’s.

Question: Where and how are biomarkers and new imaging tests being used?

Answer: At this time, they are being used by researchers investigating how brain imaging and body fluid analysis relate to the changes taking place in the brain and whether the tests can predict who is at risk for developing the clinical symptoms associated with the disease. For clinicians in research centers or with access to large medical centers, fluid biomarker and imaging tests may be used in certain cases. For example, they may be used to increase or decrease the level of certainty about a diagnosis of Alzheimer’s dementia and to distinguish Alzheimer’s dementia from other dementias. But at this stage, the tests are not available to primary care doctors because investigators are still standardizing and evaluating their use.