Alzheimer’s disease

Alzheimer’s disease, the most common cause of dementia, is a neurologic disorder that causes brain cells to shrink and die over time. A person with Alzheimer’s can expect a continual decrease in their functional ability to think, marked changes in behavior and an overall decline in social skills.

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Signs and symptoms

The "4 A's" of Alzheimer's.

The four A’s of Alzheimer’s disease are: amnesia, aphasia, apraxia and agnosia.

Amnesia. Amnesia, the most common sign of Alzheimer’s disease, refers to loss of memory.

Aphasia. Aphasia, meaning loss of ability to express or understand speech, has two forms: expressive and receptive. Expressive aphasia occurs when someone can’t find the right words or may say them incorrectly. Receptive aphasia indicates an inability to understand, receive and interpret language.

Apraxia. Apraxia represents a loss in voluntary motor skills, eventually preventing the body from physically functioning.

Agnosia. Agnosia occurs when the five senses can’t receive or correctly process information.

Diagnosing Alzheimer's disease

To start, your doctors will perform tests to help rule out other possible causes for your memory impairment. Testing for Alzheimer’s includes a physical and neurological exam, lab tests and brain imaging. Then, they will conduct additional tests to assess your ability to think, your ability to function and to pinpoint any changes in behavior.

Your doctor may also choose to perform mental status and neuropsychological testing to assess memory and other thinking skills.

Physical and neurological exam

Your doctor will assess overall neurological health by performing a physical exam that tests the following:

  • Ability to get up from a chair and walk across the room.
  • Balance.
  • Coordination.
  • Muscle tone and strength.
  • Reflexes.
  • Sense of sight and hearing.

Lab tests

In order to rule out other potential causes of memory loss, your doctor will perform blood tests that look for things like vitamin deficiencies or a thyroid disorder.

Brain imaging

Cognitive change can come from conditions other than Alzheimer’s disease, including things like stroke, trauma or tumors. That’s why doctors use MRIs, CT scans and PET scans to look at images of your brain to help them visualize abnormalities related to those conditions.

  • Magnetic resonance imaging (MRI). While MRIs may show brain shrinkage of brain regions associated with Alzheimer’s disease, MRI scans also rule out other conditions. An MRI is generally preferred to a CT scan for the evaluation of dementia.
  • Computerized tomography (CT). A CT scan, a specialized X-ray technology, produces cross-sectional images (slices) of your brain. It’s usually used to rule out tumors, strokes and head injuries.
  • Positron emission tomography (PET). A PET scan injects a low-level radioactive tracer into the blood to reveal a particular feature in the brain.

Can Alzheimer's be prevented?

Alzheimer’s cannot be prevented. However, changes in your diet and exercise can help lower your risk of getting the disease.

Consider these lifestyle choices:

The Mediterranean diet emphasizes fruits, vegetables, whole grains, legumes, fish and other seafood; unsaturated fats such as olive oils; and low amounts of red meat, eggs and sweets. It has shown some promising evidence of helping to prevent Alzheimer’s.

Vegetables, especially leafy greens, have been shown to be a particularly effective food for combatting Alzheimer’s.

Frequently Asked Questions (FAQs) about Alzheimer's

Do memory problems always mean Alzheimer's disease?

Not all memory problems indicate Alzheimer’s. Memory naturally decreases with age, but other causes can include emotional issues, medical problems, mild cognitive impairment or other types of dementia.

What is a memory screening?

A memory screening evaluates memory and other thinking skills to help determine if additional testing by a healthcare professional is needed.

What is mild cognitive impairment?

Mild cognitive impairment, also known as MCI, is a deterioration of memory or other thinking skills beyond what would be considered normal for a person’s age. Even though a drop in cognitive ability exists, it doesn’t inhibit a person’s function in social or work situations.

How many people have Alzheimer's disease?

According to the National Institute on Aging, approximately 5.8 million people in the United States age 65 and older live with Alzheimer’s disease. Of those, 80% are 75 years old and older.

Out of the approximately 50 million people worldwide with dementia, it’s estimated that between 60% and 70% have Alzheimer’s disease.

Does Alzheimer's disease occur in younger adults?

For the most part, no. Alzheimer’s is most often found in adults over the age of 65. There is a very small number of people in their 40s and 50s who are diagnosed with the disease. This is called early-onset (or younger-onset) Alzheimer disease and is defined by anyone diagnosed under the age of 65.

Is there a relationship between aluminum and the development of Alzheimer's disease?

At the current time, no compelling evidence exists that links aluminum (contained in antiperspirants, for example) with Alzheimer’s disease.

How close are you to finding a cure for Alzheimer's?

Currently, there is no cure, but there is ongoing research. Experts are hopefully optimistic about emerging treatments that can significantly slow or even stop Alzheimer’s progression.

How important is a diagnosis of Alzheimer's disease?

An early Alzheimer’s diagnosis is important for two reasons: one, it gives your treatment a better chance of being effective. And two, you’ll be a candidate for a wider variety of clinical trials.


National Insitute on Aging (NIA). Alzheimer’s Disease & Related Dementias (

Alzheimer’s Association. What is Alzheimer’s Disease? (

Center for Disease Control and Prevention (CDC). Alzheimer Disease ( Resources for People With Alzheimer’s Disease and Related Dementias. (