Alzheimer's disease

Article By:

Alexander, Gene Department of Psychology, The University of Arizona, Tucson, Arizona.

Last reviewed:July 2022

DOI:https://doi.org/10.1036/1097-8542.026550

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• Alzheimer's disease, published June 2014:Download PDF Get Adobe Acrobat Reader

A disease of the nervous system characterized by a progressive dementia that leads to profound impairment in cognition and behavior. Dementia occurs in a number of brain diseases where the impairment in cognitive abilities represents a decline from prior levels of function and interferes with the ability to perform routine daily activities (for example, balancing a checkbook or remembering appointments). Alzheimer's disease is the most common form of dementia and affects the structure of the brain (Fig. 1 and Fig. 2), particularly areas of the brain that are used for memory and other cognitive functions. In general, approximately 5% of individuals over age 65 are affected by Alzheimer's disease. The onset of the dementia typically occurs in middle to late life, and the prevalence of the illness increases with advancing age to include 25–35% of individuals over age 85. See also: Brain; Cognition; Dementia; Memory

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