Experts urge new research framework to redefine Alzheimer’s disease
Experts are pushing for a new research framework that shifts the definition of Alzheimer’s disease from one based on cognitive changes and behavioral symptoms confirmed by biomarkers to a biological construct.
Researchers hope that defining Alzheimer’s disease by biological changes in the brain associated with Alzheimer’s disease will lead to a more accurate understanding of the progression of events that lead to cognitive impairment, according to a paper published in Alzheimer’s & Dementia.
"With the aging of the global population, and the ever-escalating cost of care for people with dementia, new methods are desperately needed to improve the process of therapy development and increase the likelihood of success," Maria C. Carrillo, PhD, chief science officer of the Alzheimer's Association, said in a press release. "This new Research Framework is an enormous step in the right direction for Alzheimer's research."
The National Institute on Aging and Alzheimer’s Association (NIA-AA) published separate diagnostic recommendations in 2011 for the preclinical, mild cognitive impairment and dementia stages of Alzheimer’s disease. However, progress and changes in Alzheimer’s disease research have prompted the NIA-AA to commission experts to update the guidelines for observational and interventional research, not for clinical care.
The new research framework focusses on diagnosing Alzheimer’s disease with biomarkers — which are grouped into those of beta amyloid deposition, pathologic tau and neurodegeneration — in living people using imaging and cerebral spinal fluid samples. It also emphasizes the incorporation of severity measures using biomarkers and a grading system for cognitive impairment, according to a second press release. Specifically, it concentrates on Alzheimer’s disease as a continuum and outlines two categorical cognitive schemes for presenting the severity of cognitive impairment: one using three traditional syndromal categories and a one using a six-stage numeric structure, according to the authors.
"We have to focus on biological or physical targets to zero in on potential treatments for Alzheimer's," Eliezer Masliah, MD, director of the Division of Neuroscience at the NIA, said in a press release. "By shifting the discussion to neuropathologic changes detected in biomarkers to define Alzheimer's, as we look at symptoms and the range of influences on development of Alzheimer's, I think we have a better shot at finding therapies, and sooner."
According to the researchers, this framework seeks to create a common language that researchers can use to create and test theories about the interactions of different cognitive symptoms and pathologic processes signified by biomarkers. They highlight that this research framework should not be used yet in general medical practice nor to limit alternative testing approaches that do not use biomarkers.
"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," Richard J. Hodes, MD, director of the NIA, said in a press release. "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.” – by Savannah Demko
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