Alzheimer's disease is the most common form of dementia, affecting up to 80 percent of all individuals with any form of dementia in the United States. An estimated 5.8 million people in the United States had Alzheimer's disease in 2020, and this number is projected to grow considerably with the aging of the large group of the Baby Boomers, born in the years 1946-1964. According to the Alzheimer's Association, by 2025, there will be 7.1 million Americans with Alzheimer's, a 22 percent increase from 2020. After diagnosis with Alzheimer's disease, the average person lives up to 8 more years, although some die sooner or much later.

Non-Alzheimer's dementia is also a huge and growing problem in the United States and the world. In 2020, the Alzheimer's Association estimated there were millions suffering from some other form of a degenerative brain disease that cannot be cured. Such other forms of dementia include vascular dementia, frontotemporal lobe dementia, dementia with Lewy bodies, and Parkinson's disease dementia. Less common forms of dementia include the dementia that is associated with Huntington's disease and Creutzfeldt-Jakob disease.

The Encyclopedia of Alzheimer's Disease and Other Dementias provides a comprehensive resource for information about all aspects of these diseases/

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