Definition of Alzheimer's disease
: a degenerative brain disease of unknown cause that is the most common form of dementia, that usually starts in late middle age or in old age, that results in progressive memory loss, impaired thinking, disorientation, and changes in personality and mood, and that is marked histologically by the degeneration of brain neurons especially in the cerebral cortex and by the presence of neurofibrillary tangles and plaques containing beta-amyloid Behavioral problems, such as mood swings and agitation, may also be a part of the progression of Alzheimer's disease.— Allan Perel … the ability to differentiate normal aging-related memory changes from the impairments associated with dementia, including Alzheimer disease …— C. Munro Cullum … researchers in California have created mice carrying the gene for beta-amyloid protein, the principal component of the plaques riddling the brains of people with Alzheimer's.— Charlene Crabb
Note: Alzheimer's is often used before another noun.
Alzheimer's patients —abbreviation ADKeep scrolling for more
Keep scrolling for more
Test Your Vocabulary
Slippery Words Quiz—Changing with the Times
- What is an earlier meaning of nice?

Test your knowledge - and maybe learn something along the way.
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Word Games
Slippery Words Quiz—Changing with the Times
Do you know these earlier meanings of words?
Take the quizWords of Snow and Ice Quiz
A selection of words from the chillier parts of t...
Take the quizTrue or False?
Test your knowledge - and maybe learn something a...
Take the quizWord Winder's CrossWinder Play the game
Share Alzheimer's disease
Time Traveler for Alzheimer's disease
The first known use of Alzheimer's disease was in 1911
See more words from the same year