Alzheimer's disease is a progressive neurologic disorder that causes the brain to shrink (atrophy) and brain cells to die. Alzheimer's disease is the most common cause of dementia — a continuous decline in thinking, behavioral and social skills that affects a person's ability to function independently.
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, between 60% and 70% are estimated to have Alzheimer's disease.
The early signs of the disease include forgetting recent events or conversations. As the disease progresses, a person with Alzheimer's disease will develop severe memory impairment and lose the ability to carry out everyday tasks.
Medications may temporarily improve or slow progression of symptoms. These treatments can sometimes help people with Alzheimer's disease maximize function and maintain independence for a time. Different programs and services can help support people with Alzheimer's disease and their caregivers.
There is no treatment that cures Alzheimer's disease or alters the disease process in the brain. In advanced stages of the disease, complications from severe loss of brain function — such as dehydration, malnutrition or infection — result in death.
Memory loss is the key symptom of Alzheimer's disease. Early signs include difficulty remembering recent events or conversations. As the disease progresses, memory impairments worsen and other symptoms develop.
At first, a person with Alzheimer's disease may be aware of having difficulty remembering things and organizing thoughts. A family member or friend may be more likely to notice how the symptoms worsen.
Brain changes associated with Alzheimer's disease lead to growing trouble with:
Everyone has occasional memory lapses, but the memory loss associated with Alzheimer's disease persists and worsens, affecting the ability to function at work or at home.
People with Alzheimer's may:
Thinking and reasoning
Alzheimer's disease causes difficulty concentrating and thinking, especially about abstract concepts such as numbers.
Multitasking is especially difficult, and it may be challenging to manage finances, balance checkbooks and pay bills on time. Eventually, a person with Alzheimer's may be unable to recognize and deal with numbers.
Making judgments and decisions
Alzheimer's causes a decline in the ability to make reasonable decisions and judgments in everyday situations. For example, a person may make poor or uncharacteristic choices in social interactions or wear clothes that are inappropriate for the weather. It may be more difficult to respond effectively to everyday problems, such as food burning on the stove or unexpected driving situations.
Planning and performing familiar tasks
Once-routine activities that require sequential steps, such as planning and cooking a meal or playing a favorite game, become a struggle as the disease progresses. Eventually, people with advanced Alzheimer's often forget how to perform basic tasks such as dressing and bathing.
Changes in personality and behavior
Brain changes that occur in Alzheimer's disease can affect moods and behaviors. Problems may include the following:
Many important skills are preserved for longer periods even while symptoms worsen. Preserved skills may include reading or listening to books, telling stories and reminiscing, singing, listening to music, dancing, drawing, or doing crafts.
These skills may be preserved longer because they are controlled by parts of the brain affected later in the course of the disease.
When to see a doctor
A number of conditions, including treatable conditions, can result in memory loss or other dementia symptoms. If you are concerned about your memory or other thinking skills, talk to your doctor for a thorough assessment and diagnosis.
If you are concerned about thinking skills you observe in a family member or friend, talk about your concerns and ask about going together to a doctor's appointment.
An important part of diagnosing Alzheimer's disease includes being able to explain your symptoms, as well as perspective from a close family member or friend about symptoms and their impact on daily life. Additionally, a diagnosis of Alzheimer's disease is based on tests your doctor administers to assess memory and thinking skills.
Laboratory and imaging tests can rule out other potential causes or help the doctor better identify the disease causing dementia symptoms.
But Alzheimer's disease is only diagnosed with complete certainty after death, when microscopic examination of the brain reveals the characteristic plaques and tangles.
A diagnostic work-up would likely include the following tests:
Physical and neurological exam
Your doctor will perform a physical exam and likely assess overall neurological health by testing the following:
Blood tests may help your doctor rule out other potential causes of memory loss and confusion, such as a thyroid disorder or vitamin deficiencies.
Mental status and neuropsychological testing
Your doctor may give you a brief mental status test to assess memory and other thinking skills. Longer forms of neuropsychological testing may provide additional details about mental function compared with people of a similar age and education level. These tests can help establish a diagnosis and serve as a starting point to track the progression of symptoms in the future.
Images of the brain are now used chiefly to pinpoint visible abnormalities related to conditions other than Alzheimer's disease — such as strokes, trauma or tumors — that may cause cognitive change. New imaging applications — currently used primarily in major medical centers or in clinical trials — may enable doctors to detect specific brain changes caused by Alzheimer's.
Imaging of brain structures include the following:
Imaging of disease processes can be performed with positron emission tomography (PET). During a PET scan, a low-level radioactive tracer is injected into the blood to reveal a particular feature in the brain. PET imaging may include the following:
In special circumstances, such as rapidly progressive dementia, dementia with atypical features or early-onset dementia, other tests may be used to measure abnormal beta-amyloid and tau in the cerebrospinal fluid.
Future diagnostic tests
Researchers are working to develop tests that can measure biological signs of disease processes in the brain.
These tests, including blood tests, may improve the accuracy of diagnoses and enable earlier diagnosis before the onset of symptoms. A blood test for Plasma Aβ is currently available and recently received certification in the U.S. by the Centers for Medicare & Medicaid Services to allow distribution on the market.
Genetic testing generally isn't recommended for a routine Alzheimer's disease evaluation. The exception is people who have a family history of early-onset Alzheimer's disease. Meeting with a genetic counselor to discuss the risks and benefits of genetic testing is recommended before undergoing any tests.
Current Alzheimer's medications can help for a time with memory symptoms and other cognitive changes. Two types of drugs are currently used to treat cognitive symptoms:
In June 2021, the Food and Drug Administration (FDA) approved aducanumab (Aduhelm) for the treatment of some cases of Alzheimer's disease. This is the first drug approved in the United States to treat the underlying cause of Alzheimer's by targeting and removing amyloid plaques in the brain. The FDA approved the drug on the condition that further studies be conducted to confirm the drug's benefit. Experts also need to identify which patients may benefit from the drug.
Sometimes other medications such as antidepressants may be prescribed to help control the behavioral symptoms associated with Alzheimer's disease.
Creating a safe and supportive environment
Adapting the living situation to the needs of a person with Alzheimer's disease is an important part of any treatment plan. For someone with Alzheimer's, establishing and strengthening routine habits and minimizing memory-demanding tasks can make life much easier.
You can take these steps to support a person's sense of well-being and continued ability to function:
Various herbal remedies, vitamins and other supplements are widely promoted as preparations that may support cognitive health or prevent or delay Alzheimer's. Clinical trials have produced mixed results with little evidence to support them as effective treatments.
Some of the treatments that have been studied recently include:
Vitamin E. Although vitamin E doesn't prevent Alzheimer's, taking 2,000 international units daily may help delay the progression in people who already have mild to moderate disease. However, study results have been mixed, with only some showing modest benefits. Further research into the safety of 2,000 international units daily of vitamin E in a dementia population will be needed before it can be routinely recommended.
Supplements promoted for cognitive health can interact with medications you're taking for Alzheimer's disease or other health conditions. Work closely with your health care team to create a safe treatment plan with any prescriptions, over-the-counter medications or dietary supplements.
Omega-3 fatty acids. Omega-3 fatty acids in fish or from supplements may lower the risk of developing dementia, but clinical studies have shown no benefit for treating Alzheimer's disease symptoms.
Curcumin. This herb comes from turmeric and has anti-inflammatory and antioxidant properties that might affect chemical processes in the brain. So far, clinical trials have found no benefit for treating Alzheimer's disease.
Ginkgo. Ginkgo is a plant extract containing several medicinal properties. A large study funded by the National Institutes of Health found no effect in preventing or delaying Alzheimer's disease.
Melatonin. This supplement of a hormone that regulates sleep is being studied to determine if it offers benefits managing sleep in people with dementia. But some research has indicated that melatonin may worsen mood in some people with dementia. More research is needed.
Lifestyle and home remedies
Healthy lifestyle choices promote good overall health and may play a role in maintaining cognitive health.
Regular exercise is an important part of a treatment plan. Activities such as a daily walk can help improve mood and maintain the health of joints, muscles and the heart. Exercise can also promote restful sleep and prevent constipation — and it's beneficial for care partners, too.
People with Alzheimer's who develop trouble walking may still be able to use a stationary bike, stretch with elastic bands or participate in chair exercises. You may find exercise programs geared to older adults on TV or on DVDs.
People with Alzheimer's may forget to eat, lose interest in preparing meals or not eat a healthy combination of foods. They may also forget to drink enough, leading to dehydration and constipation.
Offer the following:
Social engagement and activities
Social interactions and activities can support the abilities and skills that are preserved. Doing things that are meaningful and enjoyable are important for the overall well-being of a person with Alzheimer's disease. These might include: