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What Does Alzheimer's Do to the Brain?

Written by Jennifer Wegerer
 about the author
2 minute readLast updated April 10, 2023

The most common form of dementia, Alzheimer’s disease affects specific parts of the brain that control language, memory, and thought. Incurable and irreversible, Alzheimer’s progresses through several stages, from mild to severe, and is the sixth leading cause of death in the United States. Alzheimer’s disease starts with minor cognitive problems like confusion, forgetfulness, and mood swings. People in the late stages may lose their ability to eat, recognize loved ones, swallow or walk.

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How Alzheimer’s impacts the brain

As the Alzheimer’s Association explains, Alzheimer’s disease is the result of a number of factors rather than a single cause.
However, experts agree that Alzheimer’s stems from the abnormal buildup of plaques (beta-amyloid protein fragments) between nerve cells in the brain.
Through each Alzheimer’s stage, tangled pieces of these plaques destroy more brain cells, eventually causing fatal damage.

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Stages of Alzheimer’s disease

There are three general stages of Alzheimer’s disease. Each is characterized by different degrees of brain damage and cognitive impairment.

1. Early Stage Alzheimer’s

The earliest stages of Alzheimer’s may begin 20 years or more before diagnosis. At this point, plaques and tangles begin to form in parts of the brain that impact learning, memory, planning, and thinking. Medical tests cannot yet detect Alzheimer’s in its earliest stages.

2. Mild to Moderate Alzheimer’s

As Alzheimer’s progresses to the moderate stages, more plaques and tangles develop in areas of the brain important to memory, planning, and thinking. They also spread to areas that affect speech. These changes cause noticeable confusion and communication problems that can impact an individual’s personal or work life. Often, Alzheimer’s is diagnosed in this stage.
Mild to moderate Alzheimer’s stages can last from two to 10 years. During this time period, individuals may struggle to recognize family members and friends. They may also experience behavior and personality changes.

3. Late Stage Alzheimer’s

The most severe stage of Alzheimer’s can last from one to five years. Most of the brain’s outer layer, which scientists have mapped to control memory, movement, thinking, and other functions, has been permanently damaged.
Widespread cell death causes the brain to shrink. At this point, individuals no longer recognize family and friends. They also lose their ability to care for themselves and communicate.

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Research on Alzheimer’s continues

Alzheimer’s treatment can help improve the quality of life for people with the disease and slow it’s progress, but the quest for new treatments continues worldwide.
The aim is to develop medications that target the brain changes that Alzheimer’s causes, but more research is needed to achieve that goal.
You can review the Alzheimer’s Association’s Treatments and Research webpage for more information about treatment of the disease.


Meet the Author
Jennifer Wegerer

The information contained in this article is for informational purposes only and is not intended to constitute medical, legal or financial advice or create a professional relationship between A Place for Mom (of which OurParents is a trademark) and the reader.  Always seek the advice of your health care provider, attorney or financial advisor with respect to any particular matter and do not act or refrain from acting on the basis of anything you have read on this site.  Links to third-party websites are only for the convenience of the reader; A Place for Mom does not recommend or endorse the contents of the third-party sites.