Karlawish, Jason

Abstract Background The National Institute on Aging, in conjunction with the Department of Health and Human Services as part of the National Alzheimer's Project Act, convened a 2020 National Research Summit on Care, Services, and Supports for Persons with Dementia and their Caregivers . This review article addresses research participation by persons living with dementia (PLWD) and their care partners in two different ways: as research participants with input on outcomes studied and as engaged research partners. Results This article summarizes each of the topics presented at this Summit session, followed by reflection from the session panelists. Lee Jennings examined collection of outcomes directly from PLWD and the potential for individualized outcomes to enhance measurement in intervention trials. Ron Petersen discussed the impact of nomenclature on research and clinical care, and how and why investigators should be mindful of the connection between dementia nomenclature and the conduct of dementia research. Tabassum Majid examined strategies for engagement in research, including specific examples of involving PLWD and their care partners (including staff in assisted living and skilled nursing facilities), and the potential for this research engagement to improve our understanding of interventions in dementia. Conclusions Research participation by PLWD and their care partners is evolving. This review summarizes three areas of opportunity and steps for researchers to work with PLWD and their care partners to design and conduct research that enhances knowledge based on what we learn from PLWD and their care partners, and creates knowledge with them.

Abstract In 2011, the National Institute on Aging and Alzheimer's Association created separate diagnostic recommendations for the preclinical, mild cognitive impairment, and dementia stages of Alzheimer's disease. Scientific progress in the interim led to an initiative by the National Institute on Aging and Alzheimer's Association to update and unify the 2011 guidelines. This unifying update is labeled a “research framework” because its intended use is for observational and interventional research, not routine clinical care. In the National Institute on Aging and Alzheimer's Association Research Framework, Alzheimer's disease (AD) is defined by its underlying pathologic processes that can be documented by postmortem examination or in vivo by biomarkers. The diagnosis is not based on the clinical consequences of the disease (i.e., symptoms/signs) in this research framework, which shifts the definition of AD in living people from a syndromal to a biological construct. The research framework focuses on the diagnosis of AD with biomarkers in living persons. Biomarkers are grouped into those of β amyloid deposition, pathologic tau, and neurodegeneration [AT(N)]. This ATN classification system groups different biomarkers (imaging and biofluids) by the pathologic process each measures. The AT(N) system is flexible in that new biomarkers can be added to the three existing AT(N) groups, and new biomarker groups beyond AT(N) can be added when they become available. We focus on AD as a continuum, and cognitive staging may be accomplished using continuous measures. However, we also outline two different categorical cognitive schemes for staging the severity of cognitive impairment: a scheme using three traditional syndromal categories and a six‐stage numeric scheme. It is important to stress that this framework seeks to create a common language with which investigators can generate and test hypotheses about the interactions among different pathologic processes (denoted by biomarkers) and cognitive symptoms. We appreciate the concern that this biomarker‐based research framework has the potential to be misused. Therefore, we emphasize, first, it is premature and inappropriate to use this research framework in general medical practice. Second, this research framework should not be used to restrict alternative approaches to hypothesis testing that do not use biomarkers. There will be situations where biomarkers are not available or requiring them would be counterproductive to the specific research goals (discussed in more detail later in the document). Thus, biomarker‐based research should not be considered a template for all research into age‐related cognitive impairment and dementia; rather, it should be applied when it is fit for the purpose of the specific research goals of a study. Importantly, this framework should be examined in diverse populations. Although it is possible that β‐amyloid plaques and neurofibrillary tau deposits are not causal in AD pathogenesis, it is these abnormal protein deposits that define AD as a unique neurodegenerative disease among different disorders that can lead to dementia. We envision that defining AD as a biological construct will enable a more accurate characterization and understanding of the sequence of events that lead to cognitive impairment that is associated with AD, as well as the multifactorial etiology of dementia. This approach also will enable a more precise approach to interventional trials where specific pathways can be targeted in the disease process and in the appropriate people.

In the history of medicine, one means to progress is when we make the decision that our assumptions and definitions of disease are no longer consistent with the scientific evidence, and no longer serve our health care needs. The arc of scientific progress is now requiring a change in how we diagnose Alzheimer's disease. Both the National Institute on Aging—Alzheimer's Association (NIA‐AA) 2011 workgroup and the International Work Group (IWG) have proposed guidelines that use detectable measures of biological changes in the brain, commonly known as biological markers, or biomarkers, as part of the diagnosis. This Special Report examines how the development and validation of Alzheimer's disease biomarkers—including those detectable in the blood or cerebral spinal fluid, or through neuroimaging—is a top research priority. This has the potential to markedly change how we diagnose Alzheimer's disease and, as a result, how we count the number of people with this disease. As research advances a biomarker‐based method for diagnosis and treatment at the earliest stages of Alzheimer's disease, we envision a future in which Alzheimer's disease is placed in the same category as other chronic diseases, such as cardiovascular disease or diabetes, which can be readily identified with biomarkers and treated before irrevocable disability occurs.

Abstract Alzheimer's disease research has often focused on the molecular brain changes that promote memory loss and other dementia‐related cognitive impairments. Many studies, for example, have used positron emission tomography (PET) imaging to measure brain levels of the beta‐amyloid protein, a key molecular suspect in Alzheimer's. In recent years, PET scans have become more prominent in clinical settings. Clinicians may use a positive PET scan—that is, a significant presence of beta‐amyloid plaques in the brain—to help determine a diagnosis of Alzheimer's disease. Yet, because beta‐amyloid PET remains a fairly new diagnostic tool, physicians and patients still have many basic questions about how and why it is used. This article addresses some of those questions. It explains what PET scans actually show, how they are employed in research and clinical trials, and when they should and should not be used to help diagnose Alzheimer's in everyday patients. The article also discusses whether cognitively healthy people should request PET scans to assess their risk for developing dementia. Information in the text will be updated in future years, as diagnostic imaging techniques for Alzheimer's disease continue to evolve.