Alzheimer's disease is a common, progressive, degenerative disease of the brain. It is characterized by loss of memory
and other cognitive functions. Among people aged 65 or older, it is the most common cause of dementia. Dementia is a group of symptoms marked by the gradual loss of mental function.
What is going on in the body?
Exactly what is happening in the brains of individual's with Alzheimer's disease is unknown. In general, Alzheimer's disease is a neurodegenerative syndrome which means that nerve cells in the brain decrease in number over time. This is evident in that the overall size of the brain in an individual with Alzheimer's disease is smaller than normal.
In addition, people who have Alzheimer's disease have a number of abnormalities that can only be seen under a microscope:
abnormal brain deposits of a protein called beta-amyloid that are called plaques.
abnormal collections of another protein called tau inside brain nerve cells.
Collections of damaged nerve fibers called tangles.
The relationship between tau and beta-amyloid collections and Alzheimer's disease is unknown particularly since these abnormalities are seen to some degree in the brains of "normal" elderly individuals. Research to define this relationship is currently on-going.
What are the causes and risks of the disease?
The cause of Alzheimer's disease is unknown. Factors that may increase the risk of developing Alzheimer's disease include the following:
age is the most important. Most people with Alzheimer's disease are older than age 65 and rarely affect individuals in their 30s, 40s, and 50s. Alzheimer's disease is seen in 1 out of 4 people over the age of 85.
genetics. Scientists have found links between the disease and certain chromosomes, including chromosomes 10, 14, 19, and 21. For example, individuals with Down syndrome, an abnormality of the 21st chromosome, have a significantly higher risk of developing Alzheimer's disease. Alzheimer's disease related to these chromosomes is relatively uncommon. Other genetic factors are likely more common. For instance, individuals with Alzheimer's disease are likely to have a certain form of a normal lipoprotein called apolipoprotein E4 (ApoE4) which suggests that an individual who produces this form of apolipoprotein is at higher risk than those who do not.
head injuries. A recent study of US armed forces veterans showed that a head injury early in life is associated with a higher risk of Alzheimer's disease and other forms of dementia as the veterans aged. Furthermore, the risk of Alzheimer's disease increased with the severity of the head injury in early life.
sex. Females has been observed to be a risk factor for Alzheimer's disease.
atherosclerosis or "hardening of the arteries". Factors such as hypercholesterolemia, high blood pressure, diabetes mellitus, elevated levels of homocysteine, smoking, obesity, and sedentary lifestyle are risk factors for atherosclerosis and also have been observed to be risk factors for the development of Alzheimer's disease.
Potentially protective factors for Alzheimer's disease include:
educational level or cognitive activities, which are tasks that involve active learning in the brain. Several research studies have shown that Alzheimer's disease is less likely to develop in individuals who have reached higher educational levels or have jobs that are more intellectually stimulating. Cognitive activities such as reading are associated with a later onset of Alzheimer's disease.
estrogen. There is some research suggesting a possible link between the hormone estrogen and Alzheimer's disease in women. Menopause, the stage of life when a woman stops having periods and her body makes little estrogen, is associated with an increase in the onset of Alzheimer's disease.
statins. A type of drug used to treat hypercholesterolemia may be protective.
non-steroidal anti-inflammatory drugs. Drugs like ibuprofen (i.e., Advil, Motrin) may be protective.
moderate alcohol use.
physical activity. Regular exercise is likely protective.
decreased fat intake. Low-fat diets are likely protective.
What are the risks to others?
Alzheimer's disease is not contagious and poses no risk to others.
What are the treatments for the disease?
The 5 medications currently approved by the Food and Drug Administration for treatment of Alzheimer's disease are:
donepezil (i.e., Aricept),
tacrine (i.e., Cognex),
galantamine (i.e., Razadyne),
rivastigmine (i.e., Exelon), and
- memantine (i.e., Namenda).
The first four medications are designed to improve memory by increasing the amount of acetylcholine in the body. Acetylcholine is released by nerve cells in the brain; some acetylcholine releasing brain nerve cells are specifically targeted in individuals with Alzheimer's disease.
Currently, tacrine is rarely prescribed. Memantine is a newer medication which works by reducing overexposure of the brain to a chemical called glutamate which harms brain cells. Unfortunately, the benefits of these medications are small.
Other medicines, such as risperidone (i.e., Risperdal) or quetiapine (i.e., Seroquel), may also be used to help behavioral problems such as hallucinations, delusions, or agitation if caused by psychotic symptoms. Some people with dementia may also need medicines for depression, anxiety, or insomnia.
Many patients with Alzheimer's will try herbs, vitamins and supplements that are heavy advertised to consumers. However, the use of any herb, vitamin or supplement should be first be discussed with the individual's primary care physician or neurologist. Many of these substances can interact with foods, other natural, over-the-counter or prescription medications or laboratory tests.
In addition, because these products are very poorly regulated in the United States, evidenced-based information on them can be difficult to obtain. However, one trustworthy source, the Natural Medicines Comprehensive Database (www.NaturalDatabase.com), has ranked the following as "possibly effective" in treating Alzheimer's. :
Acetyl-L-carnitine might slow the rate of disease progression, improve memory, and improve some measures of cognitive function and behavioral performance in some patients with Alzheimer's disease. It is more likely to show some effect in those with early-onset Alzheimer's disease who are less than 66 years of age and have a faster rate of disease progression and mental decline. Acetyl-L-carnitine has not been compared with cholinesterase inhibitors such as donepezil (Aricept).
Gingko biloba. Taking ginkgo leaf orally seems to modestly improve symptoms of Alzheimer's. Studies lasting from 3 months to a year show that ginkgo leaf extract can stabilize or improve some measures of cognitive function and social functioning in patients with multiple types of dementia. The majority of evidence indicates that ginkgo leaf extract can be modestly helpful. Some researchers suggest that the improvement with ginkgo leaf extract is roughly equivalent to a 6-month delay in disease progression; however, outcome studies have not yet verified ginkgo's effects on disease progression.
Most studies have not compared ginkgo to conventional drugs such as the cholinesterase inhibitors. However, in a preliminary comparative trial, a specific ginkgo leaf extract (EGb 761) 160 mg daily seems to be comparable to donepezil (i.e., Aricept) 5 mg daily for mild to moderate Alzheimer's dementia after 24 weeks of treatment. Indirect comparisons suggests that ginkgo might be less effective than the conventional drugs donepezil (i.e., Aricept) or tacrine (i.e, Cognex).
Idebenone. There's some evidence that taking idebenone orally slows cognitive function decline in patients with Alzheimer's disease. Idebenone appears most effective in patients with moderately severe Alzheimer's disease, based on standard Alzheimer's disease rating scales.
Lemon Balm. Taking a standardized extract of lemon balm orally, daily for 4 months, seems to reduce agitation and improve symptoms of mild to moderate Alzheimer's disease on standard Alzheimer's disease rating scales.
Phosphatidylserine. Taking phosphatidylserine orally can increase cognitive function, global improvement rating scales, and improve behavioral rating scales over 6-12 weeks of treatment. It seems to be most effective in patients with less severe symptoms and might lose its effectiveness with extended use. After 16 weeks of treatment, progression of Alzheimer's disease seems to overcome any benefit of phosphatidylserine.
Sage. Taking extracts of Salvia officinalis and Salvia lavandulaefolia orally seem to improve cognitive function in patients with mild to moderate Alzheimer's disease when used for up to 4 months.
Vinpocetine is used to treat cognitive impairment due to vascular disease, Alzheimer's disease, and other kinds of dementias. It might have a modest effect on cognitive impairment from various causes, but most studies have lasted 6 months or less. Most of the studies were published prior to 1990 and used a variety of terms and criteria for cognitive decline and dementia.
Vitamin E has been one of the most studied supplements in Alzheimer's:
There's some evidence that synthetic vitamin E (all-rac-alpha-tocopherol), 2000 IU per day is similar to selegiline (i.e., Eldepryl), and superior to placebo, for slowing cognitive function decline in patients with moderately severe Alzheimer's disease.
However, there is no benefit to taking vitamin E in combination with selegiline (i.e., Eldepryl).
Retrospective data suggest that long-term combination therapy with donepezil (i.e., Aricept) 5 mg per day and vitamin E 1000 IU per day may help slow cognitive decline in patients with Alzheimer's disease.
However, vitamin E, by itself, does not seem to slow progression from mild cognitive impairment to a diagnosis of probable Alzheimer's disease as patients with mild cognitive impairment who take vitamin E 2000 IU/day for 3 years progress to Alzheimer's disease at the same rate as those who take placebo.
Use of vitamin E should be first be discussed with an individual's healthcare professional as vitamin E in high doses can thin the blood and predispose to hemorrhage in certain individuals.
The Natural Medicines Comprehensive Database (www.NaturalDatabase.com
) has concluded that the following are "possibly ineffective" in treating Alzheimer's:
Pyridoxine (Vitamin B6)
- Vitamin C (Ascorbic Acid)
The Natural Medicines Comprehensive Database (www.NaturalDatabase.com
) has concluded that the following are "likely ineffective" in treating Alzheimer's:
- N-acetyl cysteine
The Natural Medicines Comprehensive Database (www.NaturalDatabase.com) has concluded that there is "insufficient evidence" to recommend for or against the following natural medications in treating Alzheimer's. However, research is ongoing with most of the following:
Cat's claw (Uncaria guianensis)
DHA (Docosahexaenoic Acid)
EPA (Eicosapentaenoic Acid)
Evening Primrose Oil
Gamma Linolenic Acid (GLA)
Gotu kola (Centella asiatica)
Other treatments include support and education for those caring for people with Alzheimer's. Individual and family counseling can be beneficial. Support groups have also been found to assist caregivers. As the disease progresses, many families are unable to care for the person with Alzheimer's disease at home, and placement in a special facility is needed.
What are the side effects of the treatments?
Medications used to treat Alzheimer's disease can damage the liver, so periodic liver function tests
are needed. Other side effects may include nausea, diarrhea,
insomnia, vomiting, fatigue, or muscle cramps.
What happens after treatment for the disease?
Alzheimer's disease is a degenerative disease without a cure. Treatment is lifelong. Because the course of Alzheimer's disease is unpredictable, individuals with the disease should make plans for end-of-life care while they are still able to participate in the decision-making.
Difficult issues that family members may face include:
promoting independence while making sure the individual is safe
removing driving privileges
finding supportive care among family, in an assisted living facility or nursing home
making business decisions
- determining executors of written wills and making sure advanced directives are in the individual's patient file at his or her healthcare professional's office.
How is the disease monitored?
Individuals with Alzheimer's disease will have periodic visits to the healthcare professional for evaluation and treatment. Periodic liver function tests may be ordered if the person is taking one of the medications that can cause liver damage. Any new or worsening symptoms should be reported to the healthcare professional.