Alzheimer's disease -- often called "the long good-bye" -- is the most common cause of dementia, causing gradually worsening problems with memory, judgment, other thinking skills, and behaviors.
Alzheimer's disease is a "neurodegenerative disease" -- a condition that, over time, slowly damages more and more brain cells. This damage eventually causes dementia symptoms, such as problems with memory and other skills requiring mental coordination.
Alzheimer's is not the only cause of dementia symptoms, but since it's the most common cause, people sometimes (though not quite accurately) use the terms dementia and Alzheimer's interchangeably.
More than 5 million Americans have Alzheimer's dementia; most are over age 65. The percentage of those affected rises by age; about half of all adults over age 85 have developed Alzheimer's dementia. About 200,000 adults under age 65 have the much more rare early-onset Alzheimer's (also called "young onset"), which, like the classic adult-onset Alzheimer's, is growing in prevalence.
The exact cause of Alzheimer's disease is unknown. It's a myth, however, that Alzheimer's is a normal consequence of aging or that it's always inherited. A combination of genes and, especially, environmental factors are thought to be responsible.
Risk factors include high blood pressure, heart disease, type 2 diabetes, obesity, depression, and past head injury.
Symptoms evolve over time, depending on the disease stage. Behavior is increasingly affected.
Alzheimer's is a progressive disease, and brain function usually worsens over a span of several years. The pace of decline and the specific symptoms experienced vary widely by individual, however. Some people with Alzheimer's decline rapidly over just a few years, while others may live 10 to 20 years or more with Alzheimer's dementia. Eventually a fatal disease, Alzheimer's causes death when brain function deteriorates to the point that a person can't mentally coordinate basic bodily functions, such as how to swallow. Alzheimer's is the sixth most common cause of death in the United States.
In April 2011, a panel of experts recommended new definitions of Alzheimer's disease, naming three distinct phases:
Pre-clinical Alzheimer's is a recently identified initial phase that occurs before symptoms of Alzheimer's are apparent but when biomarkers associated with Alzheimer's can be seen in the blood, brain, or cerebrospinal fluid. Experts believe this stage can last for years before symptoms become apparent. For now, this stage is mainly relevant for research purposes, because biomarker tests are not widely available and are still being interpreted; it's impossible to know when or even if symptoms might appear once markers are seen.
Mild cognitive impairment is the next phase, when symptoms have begun to appear yet aren't bad enough to really interfere with daily functioning. Not all cases of mild cognitive impairment advance to Alzheimer's dementia.
The third phase is clinical Alzheimer's disease, defined as when symptoms are apparent and other possible causes have been ruled out -- the description that comes to most people's minds when they think of Alzheimer's.
Clinical Alzheimer's disease progresses through several stages, often known as mild, moderate, and severe stages.
Each stage has characteristic symptoms:
In mild-stage Alzheimer's, people can still manage basic self-care and can communicate well, but memory changes are interfering with instrumental activities of daily living, the higher-order thinking skills one gains in the teenage years, such as driving, preparing meals, and managing money.
Someone with mild-stage Alzheimer's may:
Have difficulty with finances, transportation, and medications.
In moderate-stage Alzheimer's, people begin to have trouble with activities of daily living, which are basic skills gained during childhood, such as grooming, feeding, and toileting.
Someone with moderate-stage Alzheimer's may:
Wander from home or pace restlessly.
Experience evening agitation known as sundown syndrome.
Become very forgetful.
Have increasing difficulty with basic self-care skills, such as getting dressed and getting to the toilet.
In severe-stage Alzheimer's, people become unable to even perform the activities of daily living; basic life skills such as those gained in the first year of life (speaking, walking, continence) are affected.
Someone with severe-stage Alzheimer's may:
Become unable to talk intelligibly.
Become unable to recognize even close family.
Lose the ability to walk or sit unassisted.
When memory problems are concerning or Alzheimer's disease is suspected, it's usually best to start with one's primary care physician, who can assess symptoms and look for the other possible causes of memory loss. It's also possible to have a type of dementia that isn't Alzheimer's.
Alzheimer's test options include brief cognitive screening tests and longer neuropsychological testing to evaluate thinking skills, brain imaging tests to rule out other causes of symptoms (such as brain tumor), and a thorough physical exam. Some people with a family history of Alzheimer's are also offered genetic testing.
There's currently no cure for Alzheimer's disease. Treatment therefore focuses on managing symptoms and helping a person remain as functional as possible, for as long as possible.
Medications approved for Alzheimer's disease are used to slow the progress of memory loss and other symptoms. Unfortunately, the effect of these drugs is often small, and in some research studies up to half of people didn't benefit at all from these drugs. Other medications are sometimes used to treat specific symptoms, such as agitation, depression, or sleep issues. However, medications for these symptoms often have side effects that can limit their use.
Many non-drug therapies are available to help reduce the impact of the disease, extend independent functioning as long as possible, and improve quality of life. Some conventional therapies focus on mental stimulation and physical exercise. Nontraditional therapies include aromatherapy, music therapy, art therapy, and reminiscence therapy.
Alzheimer's caregivers typically need to learn new communication skills, how to manage personal care and hygiene, and how to understand and deal with problem behaviors, such as aggression. Also helpful: activities that help the person with Alzheimer's continue to feel productive and involved.
Because Alzheimer's erodes the ability to function independently, those with the disease become increasingly dependent on others. Spouses, adult children, and other family members shoulder a growing caregiving burden as a result. Family members often begin as long-distance caregivers but eventually become in-home caregivers.
Alzheimer's caregiving is stressful. Caregivers are vulnerable to depression, sleep problems, financial burdens, and marital strain. Caregiving stressors often sabotage ongoing at-home family caregiving care.
Types of support and resources that help include:
Learning practical skills for managing disease care.
Practicing good physical and emotional self-care.
Arranging respite care.
Hiring local resources such as in-home care providers (including elder companions and personal care assistants), home healthcare services (including skilled nursing and occupational therapy), geriatric care management, meal services, and transportation services.