Revising the Diagnostic Criteria for Alzheimer's Disease: The Use of Biomarkers and Attendant Ethical Implications.

"Alzheimer's disease (AD) accounts for approximately 70 percent of dementia cases and is characterized by the need for specialized, high cost, long-term care. It is estimated that by the year 2050, AD will affect 13.5 million individuals within the US alone, a prevalence rate representing 10% of that predicted at the global level. As such, AD stands as one of the most important health challenges of the 21st century. While initially viewed as a distinct clinicopathological entity -- with the attendant implications of synonymity between AD pathology and the clinical symptoms of AD -- advances in the neurobiology of AD have led to a revised conceptualization of AD in which the underlying pathophysiology is thought to precede the clinical diagnosis of AD by up to a decade. This has led to a growing consensus that the predementia phase of AD may represent a therapeutic window of opportunity -- a period during which disease modifying drugs may prove effective -- and has resulted in: 1) an increasing shift toward the use of biomarkers -- measures that allow for in vivo detection of AD pathophysiology; and 2) the concept of early disease modifying interventions as a strategy to prevent or delay dementia onset. Collectively, these elements have found expression in the recent revisions to the diagnostic criteria for AD, namely those advanced by the National Institute of Aging and Alzheimer's Association workgroups. While these developments signal progress in the fight against AD, they likewise bring to the fore ethical implications that merit careful consideration. These are the potential impact of a diagnosis of AD in its predementia stages and the implications of the new criteria on practicing physicians, those working in memory clinics, and society as a whole." [ABSTRACT FROM AUTHOR]