New AD Guidelines
New Diagnostic Guidelines for Alzheimer’s Disease
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Your patients may ask you to clarify some details about the highly publicized, revised guidelines for the diagnosis of Alzheimer’s disease (AD) jointly published by the Alzheimer’s Association and the National Institute on Aging in April 2011. In their first reissue in 27 years, the key difference between the old and the new guidelines is that in 1984 AD was defined primarily as a condition of dementia. The new guidelines define AD by subtle brain changes earlier in the disease rather than exclusively by advanced dementia.
The articles—collectively known as the National Institute on Aging/Alzheimer’s Association Diagnostic Guidelines for Alzheimer’s Disease—expand the definition of Alzheimer’s to include two new phases of the disease: 1) presymptomatic, and 2) mildly symptomatic but predementia. This reflects current thinking that over time, the process of AD creates distinct and measurable changes in the brains of affected people many years before memory and thinking symptoms are noticeable.
The new guidelines are designed to—
- Update widely used existing guidelines for AD originally established in 1984 by the National Institute of Neurological Disorders and Stroke (NINDS) and the Alzheimer’s Association.
- Refine existing guidelines for diagnosing mild cognitive impairment (MCI). The new guidelines formalize an emerging consensus that everyone who eventually develops Alzheimer’s experiences this stage of minimal but detectable impairment, even though it’s not currently diagnosed in most people.
- Broaden the conceptual framework for thinking about Alzheimer’s disease to include a “preclinical” stage characterized by signature biological changes (biomarkers) that occur years before any disruptions in memory, thinking or behavior can be detected. Although the new guidelines do not specify which biomarkers should be considered signatures of preclinical AD, promising investigational biomarkers include brain imaging strategies and certain proteins in spinal fluid.
- Establish a framework for eventually adding biomarker benchmarks to the diagnosis of AD. The guidelines for MCI due to AD include specific biomarkers that may be used now in research settings, with the expectation that these recommendations will evolve as knowledge advances.
Note that the guidelines do not address treatment options.
Primary Issues is pleased to provide the following key points to help you discuss these guidelines with your patients.
How are these guidelines different from the original criteria?
The first notable difference is that the new guidelines identify three stages of the disease—presymptomatic, mildly symptomatic without dementia, and AD with dementia. The early stages begin before symptoms such as memory loss occur and before a patient’s ability to carry out everyday activities are affected. The original criteria published in 1984 require that a diagnosis of AD be based on memory loss and a decline in thinking abilities severe enough to affect daily life.
The second difference has to do with criteria used to make the diagnosis. Under the old guidelines, the diagnosis of AD was based on your clinical judgment about the cause of a patient’s symptoms, taking into account reports from the patient, family members and friends, results of cognitive testing, and general neurological assessment. The new criteria and guidelines propose the addition of biomarker tests, which might provide information about biological processes underlying the observed symptoms.
What are the stages of Alzheimer’s disease identified by the new criteria and guidelines?
The three stages are 1) preclinical Alzheimer’s disease, 2) mild cognitive impairment due to Alzheimer’s disease, and 3) dementia due to Alzheimer’s disease.
Preclinical AD: Measurable changes in biomarkers that indicate the earliest signs of disease, before symptoms such as memory loss and confusion about time or place are noticeable. This reflects current thinking that Alzheimer’s begins creating measurable changes in the brain years, perhaps decades, before symptoms occur. While the criteria and guidelines identify this as a stage of Alzheimer’s disease, they do not establish diagnostic criteria that you can use now. Rather, they propose additional biomarker research to confirm the presence and stage of AD.
MCI due to AD: This stage refers to mild changes in measurable changes in memory and thinking abilities that are noticeable to the patient and to family members and friends, but that do not affect one’s ability to carry out everyday activities. Many, but not all, people with MCI go on to develop dementia due to AD. The guidelines define four levels of certainty for ruling out other causes of MCI and arriving at a diagnosis of MCI due to AD.
Dementia due to AD: Memory, thinking, and behavioral symptoms that impair a person’s ability to function in daily life.
What do these guidelines mean for patients already diagnosed with AD?
In the short term, they will probably not affect how patients with AD and their families interact with you regarding the disease. There are no new tests that you should order now. Many of the tests that may someday improve diagnostic accuracy or enable presymptomatic detection of Alzheimer’s disease are available only to people participating in research studies.
For an overview and full text of the new guidelines, visit the Alzheimer’s Association at http://www.alzheimersanddementia.org/content/ncg.
Published on April 20, 2011
Very informative, thank you.
Before, I used the old parameters and got away with it. I was just in the PRE-Preclinical category. Now would anyone tell me if I have submitted this already?
Dr. Serina
Dr. Serina,
Hello, thank you for comment on the New AD Guidelines. You asked, “Now would anyone tell me if I have submitted this already?” I am assuming you meant your comment. If I am incorrect and you meant something else, please let me know. Otherwise, the answer is no, you have not submitted your comment before. I do want to say, we appreciate your comment. Again, thank you.