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  • Updated 11.14.2023
  • Released 06.27.1994
  • Expires For CME 11.14.2026

Alzheimer disease



Alzheimer disease is the most common cause of dementia (known as major neurocognitive disorder in the fifth edition of the Diagnostic and Statistical Manual for Mental Disorders) among people over 65 years of age. In this article, the authors present an overview of the disease, including clinical manifestations, pathophysiology, etiology, and diagnostic workup. Information on results from clinical trials of diet and exercise are also included.

Historical note and terminology

Although cognitive decline in advanced age has been recognized throughout history, the understanding that it represents the result of specific disease states is more recent. In 1907 the German neurologist and pathologist Alois Alzheimer reported the case of a 56-year-old woman with progressive cognitive decline and behavior change associated with distinctive neuropathological features of senile plaques and neurofibrillary tangles (04). Although the term “Alzheimer disease” is often used synonymously with “dementia,” current theoretical frameworks distinguish the pathology of Alzheimer disease from the symptomatic expression, accounting for constructs like “preclinical Alzheimer disease” and “mild cognitive impairment due to Alzheimer disease.” For clarity and brevity in this article, “Alzheimer dementia” will be used to denote “dementia due to Alzheimer disease.”

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