For the first time in 27 years, new criteria and guidelines for the diagnosis of Alzheimer’s disease have been published by three expert workgroups spearheaded by the Alzheimer’s Association and the National Institute on Aging (NIA) of the National Institutes of Health (NIH).
The workgroups published four articles including ready-to-use clinical diagnostic criteria for Alzheimer’s disease dementia and mild cognitive impairment (MCI) due to Alzheimer’s.
“The new guidelines reflect today’s understanding of how key changes in the brain lead to Alzheimer’s disease pathology and how they relate to the clinical signs of mild cognitive impairment and Alzheimer’s disease dementia,” said Creighton Phelps, Ph.D., Program Director of the Alzheimer’s Disease Centers Program at the National Institutes of Health. “We are also beginning to be able to detect these changes at a preclinical stage, long before symptoms appear in many people. With further research on biomarkers, as set forth in the new guidelines, we may ultimately be able to predict who is at risk for development of mild cognitive impairment and Alzheimer’s dementia, and who would benefit most as interventions are developed.”
Three Stages of Alzheimer’s Disease
The current diagnostic criteria for Alzheimer’s*, for the most part, focus on reliable diagnosis when signs of problems in thinking, learning, and memory are noticeable to an individual, family, and friends. But research tells us that Alzheimer’s likely begins years, maybe even decades, prior to symptoms appearing.
The new articles refer to three phases of Alzheimer’s disease progression over time:
- Preclinical Alzheimer’s Disease – Measurable changes in biomarkers (such as brain imaging and spinal fluid chemistry) that indicate the very earliest signs of disease, before outward symptoms are visible. Currently, there are no clinical diagnostic criteria for this phase, but the group provides a scientific framework to help researchers better define this stage of Alzheimer’s.
- Mild cognitive impairment (MCI) due to Alzheimer’s Disease – Mild changes in memory and thinking abilities, enough to be noticed and measured, but not impairment that compromises everyday activities and functioning.
- Dementia due to Alzheimer’s Disease – Memory, thinking and behavioral symptoms that impair a person’s ability to function in daily life.
The authors propose that Alzheimer’s begins with a long asymptomatic period during which detrimental changes are progressing in the brain, and individuals with biomarker evidence of these changes are at increased risk for developing cognitive and behavioral impairment and progression to Alzheimer’s dementia.