April 21, 2011

Alzheimer’s Guidelines Get a Makeover

(Ivanhoe Newswire) -- It's been 27 years since the clinical diagnostic criteria for Alzheimer's disease has been revised.  Research guidelines for prior stages of the disease have been characterized to reflect a deeper comprehension of the disorder that affects someone every 70 seconds in the U.S., making it the fifth leading killer.

The initial criteria were the foremost to address the disease and described merely later stages, when symptoms of dementia had already manifested. The modernized guidelines announced today cover the full spectrum of the disease as it progressively changes over various years and stages. They describe the earliest preclinical stages of the disease, mild cognitive impairment, and dementia due to Alzheimer's pathology.

Notably, the guidelines now address the use of imaging in addition to biomarkers in blood and spinal fluid that could aid in determining whether changes in the brain and those in body fluids are due to Alzheimer's disease.  Biomarkers are becoming progressively more useful in the research setting to identify onset of the disease and to track progression but cannot yet be used consistently in clinical diagnosis without additional testing and confirmation.

"Alzheimer's research has greatly evolved over the past quarter of a century.  Bringing the diagnostic guidelines up to speed with those advances is both a necessary and rewarding effort that will benefit patients and accelerate the pace of research," National Institute on Aging Director, Richard J. Hodes, M.D., was quoted as saying.

"We believe that the publication of these articles is a major milestone for the field," William Thies, Ph.D., chief medical and scientific officer at the Alzheimer's Association, was quoted as saying. "Our vision is that this process will result in improved diagnosis and treatment of Alzheimer's and will drive research that ultimately will enable us to detect and treat the disease earlier and more effectively. This would allow more people to live full, rich lives without -- or with a minimum of -- Alzheimer's symptoms."

The aforementioned 1984 clinical criteria for Alzheimer's disease, reflecting the partial facts of the day, defined Alzheimer's as having a solitary stage, dementia, and based diagnosis exclusively on clinical symptoms. It assumed that people free of dementia symptoms were ultimately disease-free. Diagnosis was confirmed predominantly at autopsy, when the hallmarks of the disease, irregular amounts of amyloid proteins forming plaques and tau proteins forming tangles, were discovered in the brain.

Since then, research has determined that Alzheimer's may bring about changes in the brain a decade or more prior to symptoms appearing, and symptoms do not always relate to irregular changes in the brain caused by Alzheimer's. For example, some older people are found to have abnormal levels of amyloid plaques in the brain at autopsy, yet never showed signs of dementia during life. It moreover appears that amyloid deposits begin early on in the disease process but that tangle arrangement and loss of neurons occur later and may speed up just before clinical symptoms appear.

SOURCE: Alzheimer's & Dementia: The Journal of the Alzheimer's Association, April 19, 2011