Purpose of Review: This article reviews recent advances in imaging and fluid biomarkers for Alzheimer disease (AD) and their application to newly proposed diagnostic criteria across the continuum of AD.
Recent Findings: There have been remarkable developments in neuroimaging markers for AD over the past decade, most notably the advent of positron emission tomography (PET) amyloid imaging using radiotracers that label fibrillar forms of amyloid-β (Aβ). Similarly, new research in CSF markers suggests CSF levels of Aβ1−42 and phosphorylated tau may be useful in the early diagnosis of AD and prediction of cognitive decline. The National Institute on Aging and the Alzheimer’s Association recently convened three workgroups to develop joint recommendations for new diagnostic guidelines across the spectrum of AD. These recommendations incorporate biomarkers and propose updated criteria for the previously recognized stage of AD dementia, the evolving definition of mild cognitive impairment, and a newly proposed concept of stages of preclinical AD.
Summary:Recent advances in AD biomarkers have increased the ability to detect evidence of early AD pathology in vivo. These biomarkers have been incorporated into new diagnostic recommendations, but a number of challenges remain for the biomarkers to become widely applied in clinical practice.
Address correspondence to Dr Reisa Sperling, Brigham and Women’s Hospital, Memory Disorders Unit, 221 Longwood Ave, Boston, MA 02115, firstname.lastname@example.org.
Relationship Disclosure: Dr Sperling serves as a consultant for Bayer AG; Biogen Idec; Bristol-Myers Squibb Company; Eisai Co, Ltd; Janssen Pharmaceuticals, Inc; Eli Lilly and Company; Merck & Co, Inc; Neurophage Pharmaceuticals; Pfizer Inc; Hoffman-La Roche Inc; and Satori Pharmaceuticals. Dr Sperling receives research support from Alzheimer’s Association, American Health Assistance Foundation, Bristol-Myers Squibb Company, Fidelity Foundation, Massachusetts Alzheimer’s Disease Research Center, and National Institute on Aging. Dr Johnson serves as a consultant for Avid Radiopharmaceuticals, Bayer AG, Elan Corporation/Janssen Pharmaceuticals, Inc, GE Health Care, and Pfizer Inc. Dr Johnson has received honoraria and payment of travel expenses from Pfizer Inc; serves as an associate editor for the Journal of Neuroimaging; receives book royalties from Lippincott Williams & Wilkins; and receives research support from Alzheimer’s Association, Avid Pharmaceuticals, Bristol-Myers Squibb Company, Janssen Alzheimer Immunotherapy, NIH, and Pfizer Inc.
Unlabeled Use of Products/Investigational Use Disclosure: Drs Sperling and Johnson discuss the unlabeled potential future use of amyloid imaging in preclinical and prodromal stages of Alzheimer disease.