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. This 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. 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 NIA and the Alzheimer’s Association.
Under the previous guidelines, a postmortem 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 do not 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 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 brain proteins and lesions, even in people who appear free of dementia.
- Identify other pathologies 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.
Montine TJ, 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.