Jan 26, 2012

New Criteria Announced for Assessing Alzheimer’s Disease Neuropathology

Under the previous guidelines, a postmortem pathology assessment was typically conducted in the brains of people diagnosed with clinical symptoms of dementia, and then only to determine whether Alzheimer’s pathology was an underlying cause of the dementia.

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The new criteria no longer require a dementia diagnosis while the person was living, as studies suggest that Alzheimer’s develops years before it becomes clinically evident and research has revealed that the brains of even cognitively normal people may have Alzheimer’s related brain changes.

The new pathology guidelines are described in two papers. The article in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association published online on Jan. 18 provides an overview of how the guidelines were revised and describes major changes. An article published online in the Nov. 20, 2011 issue of Acta Neuropathologica provides pathologists a practical guide for the implementation of the revised guidelines.


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WHAT: The neuropathology guidelines used since 1997 to diagnose Alzheimer’s disease at autopsy have been updated to reflect a deeper understanding of Alzheimer’s and other dementias. The effort, a project of the NIH and the Alzheimer’s Association, will help pathologists characterize Alzheimer’s-related brain changes at death in people diagnosed with dementia and those who have not yet shown clinical symptoms, taking into account that the disease process may begin a decade or two before outward signs like memory loss appear. Further, the new guidelines recognize the importance of reporting pathology findings for all diseases that contribute to dementia—not just Alzheimer’s-related changes—and to correlate those findings with clinical symptoms.

The effort was led by the National Institute on Aging, the lead NIH institute on Alzheimer’s research, and the Alzheimer’s Association. The new National Institute on Aging–Alzheimer’s Association guidelines for the neuropathologic assessment of Alzheimer’s disease will be published online on January 18, 2012 in advance of print publication by Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

Under the previous guidelines, a postmortem pathology assessment was typically conducted in the brains of people diagnosed with clinical symptoms of dementia, and then only to determine whether Alzheimer’s pathology was an underlying cause of the dementia. The new criteria no longer require a dementia diagnosis while the person was living, as studies suggest that Alzheimer’s develops years before it becomes clinically evident and research has revealed that the brains of even cognitively normal people may have Alzheimer’s-related brain changes.

The revised pathology criteria provide a framework for researchers and clinicians to:
  • Report in more specific detail the amount and location of Alzheimer’s-related pathology, such as abnormal proteins and lesions in the brain, even in people who appear free of dementia.
  • Identify other pathologies, such as those seen in Lewy body disease, frontotemporal disorders, or cerebrovascular disease, that may co-exist or be confused with Alzheimer’s disease and may contribute to cognitive decline.
  • In research settings, incorporate new tools—such as biomarkers and imaging—that may correlate with pathological changes in the brain.
  • Relate the pathology to the full continuum of Alzheimer’s disease, from the earliest “preclinical” stages, to mild cognitive impairment, to dementia due to Alzheimer’s pathology, as described in the recently updated Alzheimer’s diagnostic guidelines. (To learn more about the new National Institute on Aging-Alzheimer’s Association diagnostic criteria announced in April 2011, go to Diagnostic Guidelines).

The new pathology guidelines are described in two papers. The article in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association published online on Jan. 18 provides an overview of how the guidelines were revised and describes major changes. An article published online in the Nov. 20, 2011 issue of Acta Neuropathologica provides pathologists a practical guide for the implementation of the revised guidelines.

ARTICLES:

Bradley T. Hyman, et al. National Institute on Aging-Alzheimer’s Association guidelines for the neuropathologic assessment of Alzheimer’s disease. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. (Advance online publication, January 18, 2012 at www.alzheimersanddementia.com).

Thomas J. Montine, et al. National Institute on Aging–Alzheimer’s Association guidelines for the neuropathologic assessment of Alzheimer’s disease: a practical approach. Acta Neuropathol. 2012 Jan; 123(1):1-11. Epub 2011 Nov 20. http://www.ncbi.nlm.nih.gov/pubmed/22101365

SPOKESPERSON: Dr. Creighton Phelps, Director of NIA’s Alzheimer’s Disease Centers Program, is available to discuss the article.

NIA leads the federal government effort conducting and supporting research on Alzheimer’s disease and age-related cognitive change. For more information, visit its Alzheimer’s Disease Education and Referral (ADEAR) Center site at www.nia.nih.gov/alzheimers. NIA also examines the biomedical and social and behavioral aspects of aging and the problems of older people. For more information on NIA’s aging-related research, 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.



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Original content Bob DeMarco, the Alzheimer's Reading Room