Alzheimer's disease

Definition

Alzheimer's disease is the most common cause of dementia — the loss of intellectual and social abilities severe enough to interfere with daily functioning. In Alzheimer's disease, healthy brain tissue degenerates, causing a steady decline in memory and mental abilities.

Alzheimer's disease is not a part of normal aging, but the risk of the disorder increases with age. About 5 percent of people between the ages of 65 and 74 have Alzheimer's disease, while nearly half the people over the age of 85 have Alzheimer's.

Although there's no cure, treatments may improve the quality of life for people with Alzheimer's disease. Those with Alzheimer's — as well as those who care for them — need support and affection from friends and family to cope.

Symptoms

Alzheimer's disease may start with slight memory loss and confusion, but it eventually leads to irreversible mental impairment that destroys a person's ability to remember, reason, learn and imagine.

Memory loss

Everyone has occasional lapses in memory. It's normal to forget where you put your car keys or to blank on the names of people whom you rarely see. But the memory problems associated with Alzheimer's disease persist and worsen. People with Alzheimer's may:

* Repeat things
* Often forget conversations or appointments
* Routinely misplace things, often putting them in illogical locations
* Eventually forget the names of family members and everyday objects

Problems with abstract thinking

People with Alzheimer's may initially have trouble balancing their checkbook, a problem that progresses to trouble recognizing and dealing with numbers.

Difficulty finding the right word

It may be a challenge for those with Alzheimer's to find the right words to express thoughts or even follow conversations. Eventually, reading and writing also are affected.

Disorientation

People with Alzheimer's disease often lose their sense of time and dates, and may find themselves lost in familiar surroundings.

Loss of judgment

Solving everyday problems, such as knowing what to do if food on the stove is burning, becomes increasingly difficult, eventually impossible. Alzheimer's is characterized by greater difficulty in doing things that require planning, decision making and judgment.

Difficulty performing familiar tasks
Once-routine tasks that require sequential steps, such as cooking, become a struggle as the disease progresses. Eventually, people with advanced Alzheimer's may forget how to do even the most basic things.

Personality changes

People with Alzheimer's may exhibit:

* Mood swings
* Distrust in others
* Increased stubbornness
* Social withdrawal
* Depression
* Anxiety
* Aggressiveness

Causes

No one factor appears to cause Alzheimer's disease. Instead, scientists believe that it may take a combination of genetic, lifestyle and environmental factors to trigger the onset of symptoms. While the causes of Alzheimer's are poorly understood, its effect on brain tissue is clear. Alzheimer's disease damages and kills brain cells.

Two types of brain cell (neuron) damage are common in people who have Alzheimer's:

* Plaques. Clumps of a normally harmless protein called beta-amyloid may interfere with communication between brain cells. Although the ultimate cause of neuron death in Alzheimer's isn't known, mounting evidence suggests that the abnormal processing of beta-amyloid protein may be the culprit.
* Tangles. The internal support structure for brain cells depends on the normal functioning of a protein called tau. In people with Alzheimer's, threads of tau protein undergo alterations that cause them to become twisted. Many researchers believe this may seriously damage neurons, causing them to die.

Risk factors

Age

Alzheimer's usually affects people older than 65, but can, rarely, affect those younger than 40. Less than 5 percent of people between 65 and 74 have Alzheimer's. For people 85 and older, that number jumps to nearly 50 percent.

Heredity

Your risk of developing Alzheimer's appears to be slightly higher if a first-degree relative — parent, sister or brother — has the disease. Although the genetic mechanisms of Alzheimer's among families remain largely unexplained, researchers have identified several genetic mutations that greatly increase risk in some families.

Sex

Women are more likely than men are to develop the disease, in part because they live longer.

Mild cognitive impairment

People who have mild cognitive impairment have memory problems that are worse than what might be expected for people of their age, yet not bad enough to be classified as dementia. Many of those who have this condition go on to develop Alzheimer's disease.

Lifestyle

The same factors that put you at risk of heart disease may also increase the likelihood that you'll develop Alzheimer's disease. Examples include:

* High blood pressure
* High cholesterol
* Poorly controlled diabetes

And keeping your body fit isn't your only concern — you've got to exercise your mind as well. Some studies have suggested that remaining mentally active throughout your life, especially in your later years, reduces the risk of Alzheimer's disease.

Education levels

Studies have found an association between less education and the risk of Alzheimer's. But the precise reason why this occurs is unknown. Some researchers theorize that the more you use your brain, the more synapses you create, which provides a greater reserve as you age. But it may simply be harder to detect Alzheimer's in people who exercise their minds frequently or who have more education.

Complications

In advanced Alzheimer's disease, people may lose all ability to care for themselves. This can make them more prone to additional health problems such as:

* Pneumonia. Difficulty swallowing food and liquids may cause people with Alzheimer's to inhale (aspirate) some of what they eat and drink into their airways and lungs, which can lead to pneumonia.
* Infections. Urinary incontinence may require the placement of a urinary catheter, which increases the risk of urinary tract infections. Untreated urinary tract infections can lead to more-serious, life-threatening infections.
* Injuries from falls. People with Alzheimer's may become disoriented, increasing their risk of falls. Falls can lead to fractures. In addition, falls are a common cause of serious head injuries, such as bleeding in the brain.

Tests and diagnosis

Doctors can accurately diagnose 90 percent of Alzheimer's cases. Alzheimer's disease can be diagnosed with complete accuracy only after death, when microscopic examination of the brain reveals plaques and tangles.

To help distinguish Alzheimer's disease from other causes of memory loss, doctors typically rely on the following types of tests.

Lab tests
Blood tests may be done to help doctors rule out other potential causes of the dementia, such as thyroid disorders or vitamin deficiencies.

Neuropsychological testing
Sometimes doctors undertake a more extensive assessment of thinking and memory skills. This type of testing, which can take several hours to complete, is especially helpful in trying to detect Alzheimer's and other dementias at an early stage.

Brain scans
By looking at images of the brain, doctors may be able to pinpoint any visible abnormalities — such as clots, bleeding or tumors — that may be causing signs and symptoms. Positron emission tomography (PET) can reveal areas of the brain that may be less active and the density of amyloid plaques.

* Magnetic resonance imaging (MRI). An MRI machine uses radio waves and a strong magnetic field to produce detailed images of your brain. You lie on a narrow table that slides into the tube-shaped MRI machine, which makes loud banging noises during scans. The entire procedure can take an hour or more. MRIs are painless, but some people feel claustrophobic in the machine.
* Computerized tomography (CT). For a CT scan, you lie on a narrow table that slides into a small chamber. X-rays pass through your body from various angles, and a computer uses this information to create cross-sectional images, or slices, of your brain. The test is painless and takes about 20 minutes.
* Positron emission tomography (PET). During a PET scan, you'll be injected with a low-level radioactive material, which binds to chemicals that travel to the brain. You lie on a table while an overhead scanner tracks the radioactive material. This helps show which parts of your brain aren't functioning properly. The test is painless and can be particularly useful in distinguishing between different types of dementia.

Treatments and drugs

Currently, there's no cure for Alzheimer's disease. Doctors sometimes prescribe drugs to improve signs and symptoms that often accompany Alzheimer's, including sleeplessness, wandering, anxiety, agitation and depression. But only two varieties of medications have been proved to slow the cognitive decline associated with Alzheimer's.

Cholinesterase inhibitors
This group of medications — which includes donepezil (Aricept), rivastigmine (Exelon) and galantamine (Razadyne) — works by improving the levels of neurotransmitters in the brain. But cholinesterase inhibitors don't work for everyone. As many as half the people who take these drugs show no improvement. Other people may choose to stop taking the drugs because of the side effects, which include diarrhea, nausea and vomiting.

Memantine (Namenda)
The first drug approved to treat moderate to severe stages of Alzheimer's, memantine protects brain cells from damage caused by the chemical messenger glutamate. It sometimes is used in combination with a cholinesterase inhibitor. Memantine's most common side effect is dizziness, although it also appears to increase agitation and delusional behavior in some people.

Lifestyle and home remedies

A healthy lifestyle may help prevent or postpone the development of Alzheimer's disease. Because Alzheimer's is most common in people over the age of 80, delaying the onset of the disease would increase the probability that people will die of other causes before Alzheimer's has a chance to develop.

Eat your veggies
Maintaining a healthy weight and eating a healthy diet appears to reduce the risk of developing Alzheimer's disease. Your doctor may suggest:

* Lots of fruits and vegetables
* Fish or poultry, instead of red meat
* Whole-grain breads and cereals
* Alternate sources of proteins, such as beans, nuts and seeds
* More olive oil and less saturated fat

Exercise your body
Higher levels of physical activity have been associated with a lower incidence of Alzheimer's disease.

Exercise your brain, too
Maintaining mental fitness may delay onset of dementia. Some researchers believe that lifelong mental exercise and learning may promote the growth of additional synapses, the connections between neurons, and delay the onset of dementia.

Carry a reminder calendar.
Record not just upcoming events, but things that happen and activities you need to complete on a daily basis. And check off those activities when done. If you can make this process a habit before your memory problems worsen, you'll be more likely to retain this skill as the disease progresses. If you can't remember if you took your pills or who called that morning, you can check your journal.

Alternative medicine

Vitamin E
Some studies have shown that vitamin E can slow the progression of Alzheimer's disease, while other studies have shown no benefit. Doctors now warn people against taking large dosages of vitamin E, because it can increase your risk of cardiovascular death.

Ginkgo
Some people believe that extracts from the leaves of the ginkgo biloba tree may help slow the progression of memory problems associated with Alzheimer's disease. But a recent large-scale study showed no benefit. Be aware that these preparations can interact with blood-thinning medications and cause bleeding.

Huperzine A
Made from Chinese club moss, Huperzine A appears to work in ways similar to prescription cholinesterase inhibitors. Because of the increased risk of toxic side effects, you shouldn't take Huperzine A if you're also taking a drug like donepezil (Aricept).

Coping and support

People with Alzheimer's disease often experience a mixture of emotions — confusion, frustration, anger, fear, uncertainty, grief and depression.

You can help a person cope with the disease by being there to listen, reassuring the person that life can still be enjoyed, providing unconditional love, and doing your best to help the person retain dignity and self-respect.

A calm and stable home environment reduces behavior problems. New situations, noise, large groups of people, being rushed or pressed to remember, or being asked to do complicated tasks can cause anxiety. As a person with Alzheimer's becomes upset, the ability to think clearly declines even more.

Caring for the caregiver
Providing care for a person with Alzheimer's disease is physically and emotionally demanding. Feelings of anger and guilt, frustration and discouragement, worry and grief, and social isolation are common. If you're a caregiver for someone with Alzheimer's disease, you can help yourself by:

* Asking friends or other family members for help when you need it
* Taking care of your health
* Learning as much about the disease as you can
* Asking questions of doctors, social workers and others involved in the care of your loved one
* Joining a support group

Many people with Alzheimer's and their families benefit from counseling or local support groups. Contact your local Alzheimer's Association affiliate to get connected with support groups, doctors, resources and referrals, home care agencies, supervised living facilities, a telephone help line, and educational seminars.

Prevention

Right now, there's no proven way to prevent the onset of Alzheimer's disease. Human trials of a promising vaccine against Alzheimer's had to be stopped several years ago because some of the people who received the vaccine developed a serious inflammation of the brain.

However, you may be able to reduce your risk of Alzheimer's disease by reducing your risk of heart disease. Many of the same factors that increase your risk of heart disease can also increase your risk of dementia. The main players appear to be blood pressure, cholesterol and blood glucose levels.

Keeping active — physically, mentally and socially — also seems to reduce the risk of Alzheimer's disease.