Framework : Towards a Biological Definition of Alzheimer ’ s Disease

20 In 2011 the National Institute on Aging and Alzheimer’s Association (NIA-AA) created 21 separate diagnostic recommendations for the preclinical, mild cognitive impairment, and 22 dementia stages of Alzheimers disease. Scientific progress in the interim led to an initiative by 23 the NIA-AA to update and unify the 2011 guidelines. This unifying update is labeled a “research 24 framework”, because its intended use is for observational and interventional research, not routine 25 clinical care. In the NIA AA research framework Alzheimer’s disease (AD) is defined by its 26 underlying pathologic processes which can be documented by post-mortem examination or in 27 vivo by biomarkers. The diagnosis is not based on the clinical consequences of the disease (i.e. 28 symptoms/signs) in this research framework which shifts the diagnosis of AD in living people 29 from a syndromal to a biological construct. The research framework focuses on the diagnosis of 30 AD with biomarkers in living persons. Biomarkers are grouped into those of β-amyloid 31 DRAFT AS OF 11/11/17 DO NOT DISTRIBUTE DRAFT