The research community now has a new framework toward developing a biologically-based definition of Alzheimer’s disease. This proposed “biological construct” is based on measurable changes in the brain and is expected to facilitate better understanding of the disease process and the sequence of events that lead to cognitive impairment and dementia. With this construct, researchers can study Alzheimer’s, from its earliest biological underpinnings to outward signs of memory loss and other clinical symptoms, which could result in a more precise and faster approach to testing drug and other interventions.
The National Institute on Aging (NIA), part of the National Institutes of Health, and the Alzheimer’s Association (AA) convened the effort, which as the “NIA-AA Research Framework: Towards a Biological Definition of Alzheimer’s Disease,” appears in edition of Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. Drafts were presented at several scientific meetings and offered online, where the committee developing the framework gathered comments and ideas which informed the final published document. The framework, as it undergoes testing and as new knowledge becomes available, will be updated in the future.
The framework will apply to clinical trials and can be used for observational and natural history studies as well, its authors noted. They envision that this common language approach will unify how different stages of the disease are measured so that studies can be easily compared and presented more clearly to the medical field and public.
“In the context of continuing evolution of Alzheimer’s research and technologies, the proposed research framework is a logical next step to help the scientific community advance in the fight against Alzheimer’s,” said NIA Director Richard J. Hodes, M.D. “The more accurately we can characterize the specific disease process pathologically defined as Alzheimer’s disease, the better our chances of intervening at any point in this continuum, from preventing Alzheimer’s to delaying progression,”
Evolution in thinking
This framework reflects the latest thinking in how Alzheimer’s disease begins perhaps decades before outward signs of memory loss and decline may appear in an individual. In 2011, NIA-AA began to recognize this with the creation of separate sets of diagnostic guidelines that incorporated recognition of a preclinical stage of Alzheimer’s and the need to develop interventions as early in the process as possible. The research framework offered today builds from the 2011 idea of three stages — pre-clinical, mild cognitive impairment and dementia — to a biomarker-based disease continuum.