5 Labels Add Precision to Pre-Alzheimer's & Alzheimer's Diagnosis
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Today's conventional wisdom is to catch Alzheimer’s as soon as possible. Evidence has been growing for years indicating that the earlier one starts medicines, therapies and preparations, the more effective they are. Doctors today tend to try catching Alzheimer’s at the earliest stages, before a person shows obvious signs.
These early stages have been challenging to doctors and researchers alike, in part due to the lack of a common vocabulary describing these initial phases.
A new set of 5 stages aims to improve the diagnosis and management of this early phase. Based on guidelines from the USA’s National Institute on Aging and the Alzheimer's Association, with additions recommended by the world renowned Mayo Clinic, the five stages are:
- Stage 0: Normal Alzheimer’s biomarkers and no evidence of subtle cognitive impairment
- SNAP: Suspected Non-Alzheimer’s Pathophysiology
- Stage 1: Preclinical
- Stage 2: MCI (Mild Cognitive Impairment)
- Stage 3: Alzheimer’s Dementia
Additional details on each stage appear below.
This is the first update to the Alzheimer’s diagnostic vocabulary since 1984. The original 1984 clinical criteria for Alzheimer’s defined it as having a single stage called dementia. A doctor’s diagnosis was based on an assessment of clinical symptoms. No dementia symptoms meant no Alzheimer’s.
Today’s technology affords ways of picking up Alzheimer’s indicators a decade or more before the onset of symptoms. It also allows for a finer diagnosis, as well as a better ability to distinguish between Alzheimer’s and other types of dementia.
The NIA and the Alzheimer’s Association announced three of the above stages in April. Describing the importance of the new stages, William Thies, Ph.D., chief medical and scientific officer at the Alzheimer's Association, said,
"We believe that the publication of these articles is a major milestone for the field. 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 Mayo Clinic has now issued their official recommendation to add the first two stages in the list above.
The lead author of the Mayo Clinic recommendations is Clifford R. Jack, Jr., M.D., a Mayo Clinic neurologist and the Alexander Family Professor of Alzheimer's Disease Research. He said,
"The important guidelines developed by the NIA-AA workgroup were a vital step in clarifying the progression of this devastating disease and aiding in earlier diagnosis. Our study builds on that work by recommending two additional sub-groups that merit attention."
The following is a more detailed description of the five stages for early diagnosis of Alzheimer’s:
- Stage 0 denotes subjects with normal AD biomarkers and no evidence of subtle cognitive impairment.
- SNAP: Suspected Non-AD Pathophysiology (SNAP) denotes subjects with normal amyloid PET imaging, but abnormal neurodegeneration biomarker studies.
- Stage 1 or Preclinical — The preclinical stage only applies to research settings. It describes a phase in which brain changes, including amyloid buildup and other early nerve cell changes, may already be in process. There are no obvious symptoms of dementia. In some people, amyloid buildup can be detected with PET scans and analyzing cerebrospinal fluid (CSF). The revealed biomarkers tell much to researchers. Notwithstanding, development and standardization of such biomarkers are still at an early stage. Therefore, they are only used in the lab.
- Stage 2 or Mild Cognitive Impairment (MCI) —Clarifications of the guidelines for MCI are growing in importance in the clinical setting. When a person has symptoms of memory problems, enough to be noticed and measured on tests, but not compromising a person’s independence, they are typically facing MCI. People with MCI may or may not progress to Alzheimer's dementia. Biomarker technologies, using PET scans, MRIs, and CSF analysis are rapidly progressing to offer increasingly accurate diagnosis of these early stages. Researchers are focused on developing and standardizing such biomarkers. The goal is accurate diagnosis of MCI symptoms.
- Stage 3 or Alzheimer's Dementia — The criteria for this stage outline methods for doctors to approach evaluating the causes of a patient’s Alzheimer’s. In addition, they offer the language necessary to treat or research progression of cognitive decline. The guidelines are a significant upgrade. Alzheimer's dementia’s most central characteristic used to be memory loss. Now, declines in areas of cognition that are first diagnosed include impaired reasoning or judgment, word-finding and vision/spatial issues. Today, doctors are beginning to use biomarker tests to increase their certainty about an Alzheimer's diagnosis, in addition to distinguishing Alzheimer's from other types of dementias.
In the study leading up to their recommendations, the Mayo Clinic worked with a sample of 450 people. In the sample, the stages broke down as follows:
- Stage 0: 43%
- SNAP: 23%
- Stage 1: 16%
- Stage 2: 12%
- Stage 3: 3%
The National Institute on Aging Director Richard J. Hodes, M.D., summed up the importance of this undertaking, saying,
"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."
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About Mayo Clinic: Mayo Clinic is a nonprofit worldwide leader in medical care, research and education for people from all walks of life. For more information, visit MayoClinic.com or MayoClinic.org/news.
The Alzheimer's Association is the world's leading voluntary health organization in Alzheimer's care, support and research. Their mission is to eliminate Alzheimer’s disease through the advancement of research; to provide and enhance care and support for all affected; and to reduce the risk of dementia through the promotion of brain health. For more information, visit www.alz.org. Media contact is Niles Frantz at 312-335-5777 or niles.frantz@alz.org.
The National Institute on Aging leads the federal government effort conducting and supporting research on aging and the health and well being of older people. The NIA provides information on age-related cognitive change and neurodegenerative disease specifically at its Alzheimer’s Disease Education and Referral (ADEAR) Center at www.nia.nih.gov/Alzheimers For more on health and on aging generally, go to www.nia.nih.gov. To sign up for e-mail alerts about new findings or publications, please visit either website.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
References:
- Clifford R. Jack Jr., et al. "Introduction to Revised Criteria for the Diagnosis of Alzheimer’s Disease: National Institute on Aging and the Alzheimer's Association Workgroups."
- Guy M. McKhann and David S. Knopman, et al. "The Diagnosis of Dementia due to Alzheimer’s Disease: Recommendations from the National Institute on Aging and the Alzheimer’s Association Workgroup."
- Marilyn S. Albert, et al. "The Diagnosis of Mild Cognitive Impairment due to Alzheimer's Disease: Recommendations from the National Institute on Aging and Alzheimer's Association Workgroup."
- Reisa A. Sperling, et al. "Toward Defining the Preclinical Stages of Alzheimer's Disease: Recommendations from the National Institute on Aging and the Alzheimer’s Association Workgroup."
Source:
NIH NEWS:
Alzheimer's diagnostic guidelines updated for first time in decades
MAYO CLINIC NEWS:
Mayo Clinic Study Identifies Earliest Stages of Alzheimer's Disease
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