|
Alzheimer's diseaseHighlightsAlzheimer’s Disease Dementia is significant loss of cognitive functions such as memory, judgment, attention, and abstract thinking. Alzheimer’s, the most common form of dementia, is a progressive brain disease. It affects 5 million Americans, and millions more worldwide. Risk Factors Age is the greatest risk factor for Alzheimer’s disease. Most people who develop Alzheimer’s disease are 65 years old or older, and the risk increases with age. People age 85 years and older are especially at risk for Alzheimer’s disease. Symptoms Early symptoms of Alzheimer's disease may include:
Treatment There is no cure for Alzheimer’s disease. Drug therapy aims to slow disease progression and treat symptoms associated with the disease. Clinical studies indicate that these drugs generally have only modest benefit. Patients and their families need to discuss with their doctors whether drug therapy can help improve behavior or functional abilities. They also need to discuss whether or not drugs should be prescribed early in the course of the disease or delayed. The following drugs are commonly prescribed for treatment of Alzheimer’s disease:
IntroductionAlzheimer's disease (AD) is a degenerative disease of the brain from which there is no recovery. The disease slowly attacks nerve cells in all parts of the cortex of the brain and some surrounding structures, thereby impairing a person's abilities to govern emotions, recognize errors and patterns, coordinate movement, and remember. Ultimately, a person with AD loses all memory and mental functioning. ![]() The major areas of the brain have one or more specific functions. CausesResearchers are finding specific biologic factors involved with Alzheimer's disease. Various environmental and genetic players appear to contribute to or trigger the process by which these factors destroy nerve cells leading to this disease. Biologic Factors in the BrainImaging techniques in patients with Alzheimer's disease have found significant loss of cells and volume in the regions of the brain devoted to memory and higher mental functioning. Researchers have observed specifica abnormalities during biopsies:
Other factors also play a role. The Effects of Neurofibrillary Tangles and Beta Amyloid in Alzheimer's Disease. These biologic factors appear to be involved in the development Alzheimer's disease in the following ways:
Other Proteins. Researchers have now identified other important proteins in the areas of the brain affected by Alzheimer's disease.
Oxidation and the Inflammatory ResponseResearchers are also attempting to discover why beta amyloid is so toxic to nerve cells. Some researchers are focusing on two processes in the body that may be involved with Alzheimer's disease: oxidation and the inflammatory process. Some evidence indicates that oxidation and inflammation can begin decades before Alzheimer's disease actually develops. One scenario for their role in Alzheimer's is as follows: The Role of Oxidation.
The Inflammatory Response.
Genetic FactorsGenetics certainly plays a role in early-onset Alzheimer's, a rare form of the disease that usually runs in families. Scientists are also investigating genetic targets for late-onset Alzheimer's, which is the more common form. At this time, only one gene, apolipoprotein E (ApoE) has been definitively linked to late-onset Alzheimer's disease. ApoE plays a role in the movement and distribution of cholesterol for repairing nerve cells during development and after injury. However, only a small percentage of people carry the form of ApoE that increases the risk of late-onset Alzheimer's. Other genes or combinations of genes may be involved. Environmental FactorsResearchers are also investigating environmental factors (infections, metals, industrial and other toxins) that may trigger oxidation, inflammation, and the disease process, particularly in people with a genetic susceptibility to Alzheimer's. Infectious Organisms. Slow, infectious viruses cause a number of other degenerative neurologic diseases, such as kuru and Creutzfeldt-Jakob disease. Although no specific virus has been linked to Alzheimer's, some researchers theorize that people with a genetic susceptibility to Alzheimer's may be vulnerable to the actions of certain viruses, particularly under circumstances when the immune system may be weakened. Metals. Some laboratory studies have reported excessive amounts of metal ions such as zinc, copper in the brain of people with Alzheimer's disease. Such ions may possibly change the chemical architecture of normal beta amyloid, making it more harmful. A mildly acidic environment appears to be important in the process that binds these metals to beta amyloid. Experts observe that such conditions (acidic environment and higher levels of zinc and copper) commonly occur as part of the inflammatory response to local injury. Electromagnetic Fields. Some studies on people exposed to intense electromagnetic fields (EMF) have reported a higher incidence of Alzheimer's. However, the association between EMF and Alzheimer's is very weak. Risk FactorsAlzheimer's disease is the seventh leading cause of death in American adults. It affects about 5 million Americans and 8 million more people worldwide. According to the U.S. Alzheimer’s Association, 1 in 8 people age 65 and older (and nearly 1 in 2 people over age 85) have Alzheimer’s disease. Age is the greatest risk factor for Alzheimer's disease. The number of cases of Alzheimer's disease doubles every 5 years in people over 65. By age 85, almost half of all people are afflicted. People with the disease survive, on average, half as long as similarly aged adults without the disease. With the increasing numbers of aging adults, unless effective methods for prevention and treatment are developed, Alzheimer's disease will reach epidemic proportions, afflicting about 16 million Americans within 50 years. Evidence points to older age, high blood pressure, cholesterol levels, and a family history of the disease as the most important risk factors for Alzheimer's disease. Gender and Estrogen LossSeveral studies have reported that women have a much higher risk for Alzheimer's disease than men. If there is a gender difference, it is likely to be due estrogen, the primary female hormone, which appears to have properties that protect against the memory loss and lower mental functioning associated with normal aging. Such actions include blocking production of beta amyloid, offering antioxidant protection, and regulating blood sugar (glucose) levels in the brain. The drop in estrogen levels after menopause may explain a higher risk for Alzheimer's disease in older women than in men. (Testosterone, the male hormone, converts to estrogen, which may help protect men.) Studies have been mixed, however, on the association between the decline in natural estrogen levels and mental functioning in older women. Family History and Population DifferencesPeople with a family history of the disease are at higher than average risk for Alzheimer's disease. Researchers are identifying important genetic factors, notably the ApoE4 gene, that may be responsible for late- and early-onset cases. Dietary and other cultural factors that increase the risk for hypertension and unhealthy cholesterol levels may also play a role. For example, a study of Japanese men showed that their risk increased if they emigrated to America. And the disease is much less common in West Africa than in African-Americans, who share the same or higher risk with Caucasians in America. Risk Factors for Cardiovascular DiseaseHigh blood pressure and unhealthy cholesterol levels -- the same important risk factors for heart disease and stroke -- have been suggested as risk factors for Alzheimer's disease. ![]() Blood pressure is the force applied against the walls of the arteries as the heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped and the size and flexibility of the arteries. High Blood Pressure. Studies have reported an association between Alzheimer's disease and systolic hypertension (the higher and first number in blood pressure measurement). High blood pressure can cause problems with the vascular system, which is responsible for delivering blood to the brain. Patients may have many small mini- strokes but don't notice them. Dementia that develops as a result of these strokes is called multi-infarct dementia. The role of high blood pressure in the development of Alzheimer's disease is inconclusive. High Cholesterol Levels. Research indicates an association between high cholesterol levels and Alzheimer's disease in some people. One theory is that cholesterol regulates the processing and accumulation of amyloid beta-protein. Diabetes. Patients with diabetes often have high blood pressure, lipid imbalances, and circulatory disorders that affect the heart and vascular system, which have been suggested to increase the risk for Alzheimer’s. However, the evidence to support a role of diabetes in the development of Alzheimer's disease is inconclusive. High Homocysteine Levels. Homocysteine, an amino acid, has been identified as a modest risk factor in heart disease. It has also been associated with a higher risk for Alzheimer's disease. High levels are general due to deficiencies of the B vitamins B6, B12, and folate. Such vitamins are also related to nerve protection. Researchers theorize that homocysteine impairs the ability of DNA to repair nerve cells. The weakened cells are then more vulnerable to the harmful effects of oxidized beta amyloid. However, research has not shown that giving patients vitamin B6 and B12 prevents or treats Alzheimer's disease. Other Risk Factors Associated with Alzheimer's DiseaseLower Education and Economic Groups. Several studies have reported either a higher risk for Alzheimer's disease in people with less education or a lower risk for Alzheimer's disease in those who remain mentally active. Some experts speculate that learning itself may stimulate more neurons to grow and thus create a larger reserve in the brain so that it takes longer for brain cells to be destroyed. Some evidence suggests that early malnutrition, which is more likely to occur in lower income and educational groups, has been associated with smaller brains and with Alzheimer's disease in old age. Low-birth weight can cause problems in growth factors that could affect both mental and physical health later on in adulthood. Small Head Size. The size of the skull is fixed by age 7. Brain size approximates the head size until old age, when it begins to shrink. Some evidence has reported an association between small head size (and therefore less brain volume) and Alzheimer's disease. Nevertheless, other studies have found no association between a small head size and Alzheimer's disease. Some experts suggest that the relationship observed in other research may simply be due to social and economic factors, such as malnutrition or low birth weight, which have been associated with both Alzheimer's disease and small head size. Small head size independent of other factors, they argue, does not pose a higher risk for either Alzheimer's disease or low intelligence. Head Injury. Some studies have suggested an association between serious head injuries in early adulthood and the development of Alzheimer's. While a dramatic brain injury can certainly alter cognitive function, its role in the development of Alzheimer's disease is inconclusive. PreventionAlthough there is no strong evidence that any lifestyle change can prevent Alzheimer's disease, studies suggest that certain behaviors may help protect against mental decline. In particular, medications and lifestyle choices that protect the heart may be of specific importance. Various preventive drugs are under investigation, including antioxidant and anti-inflammatory therapies. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) as PreventionSeveral trials have investigated the use of anti-inflammatory drugs (including aspirin) in preventing Alzheimer's disease. The trials were based on the premise that because inflammation may be involved in the process of Alzheimer’s disease, anti-inflammatory drugs may help to prevent it. Evidence from these trials indicates that aspirin, naproxen, and celecoxib do not appear to reduce the risk for Alzheimer’s. Also, some non-steroid anti-inflammatory drugs (NSAIDs) and Cox-2 inhibitors have been associated with cardiovascular risks. NSAIDs have also been investigated for treatment of Alzheimer's disease. To date, rigorous studies have failed to show a benefit. Heart-Protective Medications and BehaviorsThe same lifestyle and medical choices that reduce risk factors for heart disease and diabetes may help lower the risk for Alzheimer's disease. Blood Pressure Drugs. Because high blood pressure is associated with increased risk of Alzheimer’s, researchers have been studying whether blood pressure medication can reduce this risk. Good blood pressure control may help to prevent the onset of Alzheimer's. Statins. Statins are common drugs used to lower cholesterol levels. In past years, a number of studies reported a significantly lower risk for Alzheimer's disease in patients who took statins. However, newer studies have failed to prove that statins can help prevent Alzheimer's disease. Male and Female Hormone Replacement TherapiesHormone Therapy. Hormone replacement therapy (HT) has been studied for years for health effects after menopause, including its effect on mental decline. A number of studies, including a major 2003 analysis, have found no differences in mental performance or protection from Alzheimer's disease in women taking HT compared to non-users. Based on these results, researchers from the National Institute on Aging (NIA) recommended against prescribing combination hormone therapy to older women for maintaining or improving cognitive function. It is even possible that women ages 65 years and older who take estrogen-only HT have a slightly increased risk of developing dementia. Testosterone. Some testosterone converts to estrogen, which may be why older men appear to have a lower risk for Alzheimer's disease than older women. Animal studies have suggested that testosterone may help reduce levels of beta amyloid. There is also some evidence that low testosterone levels may be a particular risk factor in men with the ApoE4 gene. Some experts believe that giving testosterone to elderly men, and combinations of testosterone and estrogen to older women, may prove to be protective. However, the evidence is far from conclusive and does not come from high quality studies. Side effects of testosterone in women include increased body hair, acne, fluid retention, anxiety, and depression. Long-term benefits or serious adverse effects are unknown. DHEA. Dehydroepiandrosterone (DHEA) is a male-like hormone in the body that declines with age. Some studies claim that it may help reduce mental decline in older women, but not in older men. Evidence is far from conclusive, however. While its effect on cancer-cell growth is unknown, some evidence indicates that high levels may increase cancer risk. In any case, DHEA is not regulated, and brands vary widely in their content. Dietary FactorsBecause Alzheimer's disease rates vary among different populations, investigators are researching how diet can help in prevention. Caloric intake itself may play a role in brain health. However, there is no evidence from randomized controlled trials that any specific diets or diet supplements prevent or treat Alzheimer's disease. Fats and Oils. Some studies suggest an association between fat and Alzheimer's disease, including a lower prevalence of Alzheimer's disease in countries where fat intake is low. In general, the recommended dietary goal is to limit total fat intake to 25 - 35% of total daily calories. But not all fats are alike. Unhealthy fats include saturated fats (contained in animal products such as meat) and trans-fatty acids (contained in fast foods and commercially baked products). The American Heart Association recommends limiting saturated fat intake to less than 7% of total daily calories and trans-fatty acid intake to less than 1% of total daily calories. [For more information, see In-Depth Report #43: Heart-healthy diet.] It is best to replace saturated fats and trans-fatty acids with unsaturated fats from plant and fish oils. Omega-3 fatty acids are excellent sources of unsaturated fats. Docosahexaenoic acid (DHA) is a type of omega-3 fatty acid found in fish oil. In 2007, the U.S. National Institutes of Health launched a large-scale clinical trial to evaluate whether DHA supplements can slow the progression of cognitive and functional decline in people with mild-to-moderate Alzheimer’s disease. ![]() Omega-3 fatty acids are found in oily fish and flaxseed and canola oils. Fruits and Vegetables. According to several studies, eating plenty of darkly colored fruits and vegetables may slow brain aging. Blueberries, which are very rich in antioxidants, are of particular interest. A 2006 study of over 3,000 elderly adults found that consumption of vegetables (especially green leafy vegetables) helped reduce the rate of cognitive decline, but fruit intake had no effect. Alcohol. Some studies have suggested that moderate intake of alcohol (one or two drinks a day) may protect the aging brain, possibly by releasing acetylcholine, the chemical in the brain that is deficient in Alzheimer's disease. Not all studies have been positive. In any case, heavy alcohol consumption offers no protection and is dangerous. Folate and Vitamin B12. Some studies suggest that deficiencies of vitamins B6, B12, and folate (folic acid) may be a risk factor for Alzheimer' diseases. Deficiencies in these vitamins can increase homocysteine levels, which some research associates with a higher risk for Alzheimer's disease. Foods containing folate include avocados, bananas, oranges, asparagus, green leafy vegetables, and dried beans. While some studies have described a benefit with administration of fully, vitamin B12, or vitamin B6, there is no good evidence from randomized controlled trials that these supplements prevent Alzheimer's disease. Antioxidant Supplements. Much research on Alzheimer's disease has indicated that oxidation (release of damaging unstable particles) may play an important role in the disease process. Some reports, including a large 2002 population study, have suggested that vitamin E intake, from food or supplements, may protect against mental decline. Other studies suggest that vitamin E protects only those who carried the ApoE4 gene. Most of the evidence finding any benefits from other antioxidants comes from using a combination of antioxidant vitamins, such as vitamins C and E, but not from using them separately. However, there is no strong evidence of protection to date from using antioxidant supplements. Other Health BehaviorsPhysical Exercise. Studies indicate that exercise may help prevent the development of Alzheimer’s disease and other forms of dementia. A 2006 study found that older adults (65 years and older) who exercised three times a week reduced their risk for Alzheimer’s by about 40%. Exercise in the study included walking, hiking, aerobics, calisthenics, swimming, water aerobics, weight training, and stretching. Mental Exercise. Cognitive training that includes exercises to stimulate memory, reasoning, and mental processing speed may help improve both mental ability and enable patients to handle daily living tasks -- such as performing housework, managing money, and preparing meals. Other studies indicate that participating in intellectually engaging activity (such as doing crossword puzzles or learning a new language) may help reduce the risk of Alzheimer’s disease. SymptomsThe early symptoms of Alzheimer's disease (AD) may be overlooked because they resemble signs of natural aging. Older adults who begin to notice a persistent mild memory loss of recent events may have a condition called mild cognitive impairment (MCI). MCI is now believed to be a significant sign of early-stage Alzheimer's in older people. Studies now suggest that older individuals who experience such mild memory abnormalities can later develop Alzheimer's disease. Early symptoms of Alzheimer's disease may include:
DiagnosisA definitive test to diagnose Alzheimer's disease, even in patients showing signs of dementia, has not yet been developed. A number of expert groups have developed criteria to help diagnose Alzheimer's disease and rule out other disorders. A diagnosis often involves answering questions about the patient:
Other steps involved in making a decision include laboratory tests (EEG and possibly tests to rule out other diseases) and psychological testing to determine the presence of dementia. Ruling out Conditions of Normal Aging that Can Cause Alzheimer's-like SymptomsAlthough some memory impairment occurs in many people as they age, only some of these people develop Alzheimer's disease. Many similar symptoms can occur in healthy older individuals from other conditions associated with aging:
Ruling out Other Causes Memory Loss or DementiaThe first step in diagnosing Alzheimer's disease is to rule out other conditions that might cause memory loss or dementia. There are a number of causes for dementia in the elderly besides Alzheimer's disease:
Experts believe that 60% of cases of dementia are due to Alzheimer's, 15% to vascular injuries, and the rest are a mixture of the two or caused by other factors. Vascular Dementia. Vascular dementia is primarily caused by either multi-infarct dementia (multiple small strokes) or Binswanger's disease (which affects tiny arteries in the midbrain). One major analysis suggested that patients with vascular dementia have better long-term verbal memory than patients with Alzheimer's disease, but poorer executive function (less ability to integrate and organize). Lewy Bodies Variant. Lewy bodies are abnormalities found in the brains of patients with both Parkinson's disease and Alzheimer's. They can also be present in the absence of either disease; in such cases, the condition is called Lewy bodies variant (LBV). In all cases, the presence of Lewy bodies is highly associated with dementia. LBV was defined in 1997, and some experts believe it may be responsible for about 20% of people who have been diagnosed with Alzheimer's. They can be difficult to distinguish. Compared to Alzheimer's disease patients, those with LBV may be more likely to have hallucinations and delusions early on, to walk with a stoop (similar to Parkinson's disease), to have more fluctuating attention problems, and to perform better than Alzheimer's disease patients on verbal recall but less well with organizing objects. Parkinson's Disease. Dementia is about six times more common in the elderly Parkinson patient than in the average older adult. It is most likely to occur in older patients who have had major depression. Unlike in Alzheimer's, language is not usually affected in Parkinson's related dementia. Visual hallucinations occur in about a third of people on long-term medications. ![]() Parkinson's disease is a slowly progressive disorder that affects movement, muscle control, and balance. Part of the disease process develops as cells are destroyed in certain parts of the brain stem, particularly the crescent-shaped cell mass known as the substantia nigra. Nerve cells in the substantia nigra send out fibers to tissue located in both sides of the brain. There the cells release essential neurotransmitters that help control movement and coordination. Frontotemporal Dementia (FTD). Once considered rare, FTD is now considered to be the second most common cause of early-onset dementia. People who develop this condition tend to be in their mid-fifties although it can develop later on. It results in greater behavioral impairment (apathy, reduced empathy, poor self-care, unrestrained behavior) than with Alzheimer's disease. It may also be marked by speech problems and early incontinence. Brain imaging scans can help diagnose this problem. Other Conditions that Cause Similar Symptoms. Some elderly people have a condition called mild cognitive impairment, which involves more severe memory loss than normal but no other symptoms of Alzheimer's. A number of conditions, including many medications, can produce symptoms similar to Alzheimer's:
It is important that the doctor recognize any treatable conditions that might be causing symptoms or worsening existing dementia caused by Alzheimer's or vascular abnormalities. Psychological TestingA number of psychological tests are used or being developed to assess difficulties in attention, perception, and memory and problem-solving, social, and language skills. Experts are researching specific tests that may help identify early on people with mild memory impairment who are at high risk for Alzheimer's disease.
ElectroencephalographyElectroencephalography (EEG) traces brain-wave activity. In some patients with Alzheimer's disease this test reveals "slow waves." EEG data helps distinguish a potential patient with Alzheimer's disease from a patient with severe depression, whose brain waves are normal. Imaging TestsImaging tests include magnetic resonance imaging (MRI), positron-emission tomography (PET), and single photon emission computed tomography (SPECT). These tests are sometimes used to rule out other disorders, such as multi-infarct dementia, stroke, blood clots, and tumors. Research is being conducted to determine if these tests can help to confirm a diagnosis of Alzheimer's disease and improve understanding of disease progression. Researchers hope that imaging tests may also be able to provide diagnoses of Alzheimer’s disease while it is still in its early stages. In 2006, scientists developed a new imaging molecule called FDDNP that they hope will enable earlier detection of Alzheimer’s disease. Research also continues on Pittsburgh compound B, a tracer molecule used in PET brain scans to highlight beta-amyloid protein deposits. Results from all this research may help to define potential drug targets and aid in the development of new Alzheimer's drugs. In 2005, the National Institute of Aging, in collaboration with industry partners, launched the $60 million Alzheimer's Disease Neuroimaging Initiative (ADNI). This landmark 5-year clinical trial, which will be conducted at 50 sites throughout the United States and Canada, will investigate whether neuroimaging techniques, such as MRI and PET scans, can be combined with biomarkers and neuropsychological tests to measure the progression of AD and mild cognitive impairment. In 2004, the U.S. Medicare system expanded insurance coverage of PET scans for eligible beneficiaries who meet specific diagnostic criteria for both Alzheimer's disease and fronto-temporal dementia. Medicare also covers the costs for patients enrolled in its agency-approved imaging clinical trials. Investigational Tests.Blood Tests. Blood tests are currently used to check for anemia and other disorders that can produce dementia symptoms. Investigators are researching serum biomarkers, such as the iron transport protein p97, that might help detect the presence of Alzheimer's disease. Cerebrospinal Fluid Test. Scientists are developing new nanotechnology screening methods that may eventually be used to identify Alzheimer's disease while it is still in its earliest stages and before plaque deposits accumulate. In 2005, a research team announced it had used a bio-barcode assay to detect tiny amounts of a protein called amyloid-beta-derived diffusable ligand (ADDL) in cerebrospinal fluid. ADDLs may be involved in cognitive decline and are a potential biomarker for early stage Alzheimer's disease. Tests for other proteins are also being developed. Odor Test. Investigators are also using the impairment of smell in Alzheimer's disease to develop tests that require patients to distinguish between odors. Determining Severity after a Diagnosis Has Been MadeOnce a diagnosis has been made, some experts observe that certain factors at the time of diagnosis indicate a higher risk for a more rapid decline:
MedicationsMost drugs used to treat Alzheimer's, and those under investigation, are aimed at slowing progression. There are no cures to date. In addition, the improvements from some of these drugs may be so modest that patients and their families may not notice benefit. Even in these cases, however, the drugs may delay the need for admission to nursing homes. There are currently two drug classes that have been approved by the U.S. Food and Drug Administration (FDA) to treat the cognitive symptoms of Alzheimer's disease:
All of the drugs currently approved for treatment of Alzheimer's disease are expensive. Likewise, while there are generally no serious risks associated with these medications, these drugs have a number of bothersome side effects, including indigestion, nausea, vomiting, diarrhea, loss of appetite, muscle cramps, and fatigue. Patients and caregivers should ask their doctors the following questions about when and if to use these drugs:
Cholinesterase InhibitorsCholinesterase inhibitors are designed to protect the cholinergic system, which is essential for memory and learning and is progressively destroyed in Alzheimer's. These drugs work by preventing the breakdown of the brain chemical acetylcholine and are recommended for the treatment of mild-to-moderate Alzheimer's. The first cholinesterase inhibitor, tacrine, was approved in 1993 but is rarely prescribed today due to safety concerns. The three most commonly prescribed cholinesterase inhibitors are donepezil (approved in 1996), rivastigmine (approved in 2000), and galantamine (approved in 2001). Cholinesterase inhibitors may increase the risk for gastrointestinal bleeding or ulcers, and patients should be cautious about using these medicines with NSAIDs (which can also cause gastric irritation). Common side effects of cholinesterase inhibitors, especially when taken at higher doses, may include nausea, vomiting, diarrhea, and upset stomach.
About half of patients with mild-to-moderate disease show slight improvement with these drugs. Comparative studies have reported little differences in effectiveness among them. All drugs have gastrointestinal side effects, including nausea. Of note, some of the drugs often used in elderly Alzheimer's disease patients are known as anticholinergics and may offset the effects of the Alzheimer's disease pro-cholinergic drugs. Such drugs include antihistamines, antipsychotic drugs, and some anti-incontinence drugs. In any case, the benefits of these drugs are far from dramatic. In fact, many experts have reservations about developing any additional drugs that affect the cholinergic system since, at best, they only slow progression and do not appear to affect the basic destructive disease process. When patients go off the drugs, the deterioration continues. N-methyl-D-aspartate (NDMA) Receptor AntagonistMemantine (Namenda) is approved for treatment of moderate-to-severe Alzheimer’s disease. (Most cholinesterase inhibitors are used to treat mild-to-moderate stages of the disease.) By blocking NDMA receptors, memantine protects against the overstimulation of glutamate, an amino acid that excites nerves and, in excess, is a powerful nerve-cell killer. Memantine is prescribed either alone or in combination with donepezil. Studies indicate that memantine may help improve cognitive function and delay the progression of Alzheimer’s disease for up to 1 year. Side effects are generally mild but may include dizziness, drowsiness, or fainting. In one study of effects on moderate-to-severe Alzheimer's, patients who received memantine showed a small but statistically significant benefit in cognitive function and performance of daily abilities compared with those patients who were given placebo. Although cholinesterase inhibitors and memantine are the best available medications for Alzheimer's, their benefits are, unfortunately, quite modest. More effective methods of prevention and treatment are urgently needed. Nicotine ReplacementNicotine enhances the actions of the cholinergic system (which is depleted in Alzheimer's disease) and is known to improve concentration and memory in the short term. Some studies have suggested that nicotine may protect nerve cells and help prevent the formation of beta amyloid. Research to date, however, has found no strong evidence of improvement in Alzheimer's disease with nicotine replacement methods. No one should smoke to prevent or treat Alzheimer's disease. Herbs and Dietary SupplementsManufacturers of herbal remedies and dietary supplements do not need FDA approval to sell their products. Just like a drug, herbs and supplements can affect the body's chemistry, and therefore have the potential to produce side effects that may be harmful. There have been several reported cases of serious and even lethal side effects from herbal products. Always check with your doctor before using any herbal remedy or dietary supplement. Ginkgo Biloba. Ginkgo biloba is a common herb that has antioxidant properties and appears to increase blood flow to the brain. Studies are reporting that a ginkgo biloba extract, called Egb 761, may slightly improve the memory of patients with mild-to-moderate Alzheimer's disease. The herb poses a small increased risk for bleeding, which may be hazardous in combination with other blood-thinning medications, such as warfarin or high-doses of vitamin E. Turmeric. Studies suggest that circumin, a compound found in the spice turmeric, has properties that may protect against the Alzheimer's disease process. Melatonin. Melatonin, a natural hormone involved in sleep regulation, is of interest to researchers. It is an antioxidant, may break down beta amyloid, and is able to pass through the blood-brain barrier. Deficiencies have been observed in patients with Alzheimer's disease. A number of studies report that melatonin may improve sleep habits in these patients. Some studies reported slower progression of mental impairment. Investigational DrugsA number of drugs are being investigated for treatment and prevention of Alzheimer's disease. Intense areas of research are focusing on drugs that prevent or reduce beta amyloid build-up. Drugs in late-stage clinical trials include:
Treating Symptoms Associated with Alzheimer'sDepression. Major depression with dementia that occurs in elderly people may be an early sign of Alzheimer's. In such cases, it precedes Alzheimer's by 2 years or less. (It is, in fact, sometimes difficult to differentiate major depression from early-stage Alzheimer's disease.) Antidepressants known as selective serotonin reuptake inhibitors (SSRIs), including fluoxetine (Prozac) and sertraline (Zoloft), may be effective in relieving depression, irritability, and restlessness associated with Alzheimer's in some patients. Apathy. Depression is often confused with apathy. An apathetic patient lacks emotions, motivation, interest, and enthusiasm while a depressed patient is generally very sad, tearful, and hopeless. Apathy responds to stimulants, such as methylphenidate (Ritalin), rather than antidepressants. Psychosis. Antipsychotic drugs are used to treat verbally or physically aggressive behavior and hallucinations. Because older antipsychotic drugs, such as haloperidol (Haldol), have severe side effects, most doctors now prescribe newer atypical antipsychotics, such as risperidone (Risperdal) or olanzapine (Zyprexa). However, these newer antipsychotic drugs still can cause serious side effects, including confusion, sleepiness, and Parkinsonian-like symptoms. In addition, studies indicate that their safety risks may outweigh any possible benefits. Studies indicate that both atypical and older antipsychotics produce a slightly increased rate of death in patients with Alzheimer’s disease or dementia and that atypical antipsychotics work no better than placebo in controlling psychosis, aggression, and agitation in patients with Alzheimer’s. Most doctors recommend delaying prescribing antipsychotic medication unless absolutely necessary. They recommend first trying behavioral treatments and controlling changes in the patient’s environment and routine. Anti-seizure drugs, such as carbamazepine (Tegretol) or valproate (Depakote), can also sometimes treat agitation and other psychotic symptoms. Non-drug treatments, such as bright light boxes, are also showing promise for managing psychotic and behavioral symptoms. Disturbed Sleep. Patients with Alzheimer's disease commonly experience disturbances in their sleep/wake cycles. Moderately short-acting sleeping drugs, such as temazepam (Restoril), zolpidem (Ambien), or zaleplon (Sonata), or sedating antidepressants, such as trazodone (Desyrel, Molipaxin), may be useful in managing insomnia. Some research suggests that exposure to brighter-than-normal artificial light during the day for patients with normal vision may help reset wake/sleep cycles and prevent nighttime wandering and sleeplessness. Trials on melatonin, a natural hormone that helps trigger sleep at night, are in progress. StagesThe lifespan of patients with Alzheimer's is generally reduced, although a patient may live anywhere from 3 - 20 years after diagnosis. The final phase of the disease may last from a few months to several years, during which time the patient becomes increasingly immobile and dysfunctional. Caregivers should understand the phases of this illness in order to help determine their own capacities for dealing with this painfully sad disease. Home Treatment in Early StagesTelling the Patient. Often doctors will not tell patients that they have Alzheimer's. If a patient expresses a need to know the truth, it should be disclosed. Both the caregiver and the patient can then begin to address issues that can be controlled, such as access to support groups and drug research. Mood and Emotional Behavior. Patients display abrupt mood swings, and many become aggressive and angry. Some of this erratic behavior is caused by chemical changes in the brain. But it may also be due to the experience of losing knowledge and understanding of one's surroundings, causing fear and frustration that patients can no longer express verbally. The following recommendations for caregivers may help soothe patients and avoid agitation:
Although much attention is given to the negative emotions of patients with Alzheimer's disease, some patients become extremely gentle, retaining an ability to laugh at themselves or appreciate simple visual jokes even after their verbal abilities have disappeared. Some patients may seem to be in a drug-like or "mystical" state, focusing on the present experience as their past and future slip away. Encouraging and even enjoying such states may bring some comfort to a caregiver. There is no single Alzheimer's personality, just as there is no single human personality. All patients must be treated as the individuals they continue to be, even after their social self has vanished. Appearance and Cleanliness. For the caregiver, grooming the patient may be an alienating experience. For one thing, many patients resist bathing or taking a shower. Some spouses find that showering with their afflicted mate can solve the problem for a while. Often patients with Alzheimer's disease lose their sense of color and design and will put on odd or mismatched clothing. It is important to maintain a sense of humor and perspective and to learn which battles are worth fighting and which ones are best abandoned. Driving. As soon as Alzheimer's is diagnosed, the patient should be prevented from driving. Wandering. A potentially dangerous trait is the patient's tendency to wander. At the point the patient develops this tendency, many caregivers feel it is time to seek out nursing homes or other protective institutions for their loved ones. For those who remain at home, the following precautions are recommended:
Speech Problems. Some evidence suggests that speech therapy combined with Alzheimer's disease medications may be helpful for maintaining verbal skills patients with mild symptoms. Sexuality. In many cases, the patient becomes uninhibited sexually. At the same time, the patient's physical deterioration and receding capacity to recognize the spouse as a known and loved individual can make sexual activity unattractive for the caregiving spouse. Other patients may lose interest in sex. If sexual issues are a problem, they should be discussed openly with the doctor. Ways should be found to maintain non-sexual physical affection that can bring comfort to both the patient and the spouse. Home Treatment During Later StagesPatients with Alzheimer's disease need 24-hour a day attention. Even if the caregiver has the resources to keep the patient at home during later stages of the disease, outside help is still essential. If available, home visits by a health profession can have a favorable impact on survival and delay the need for a nursing home. Medicare now covers many Alzheimer's services, and patients should be able to stay at home longer than previously. Incontinence. A patient's incontinence is generally devastating to the caregiver and a primary reason why many caregivers decide to seek nursing home placement when the patient reaches this stage. When the patient first shows signs of incontinence, the doctor should make sure that it is not caused by an infection. Urinary incontinence may be controlled for some time by trying to monitor times of liquid intake, feeding, and urinating. Once a schedule has been established, the caregiver may be able to anticipate incontinent episodes and get the patient to the toilet before they occur. Immobility and Pain. As the disease progresses, patients become immobile, literally forgetting how to move. Eventually, they become almost entirely wheelchair-bound or bedridden. Bedsores can be a major problem. Sheets must be kept clean, dry, and free of food. The patient's skin should be washed frequently, gently blotted thoroughly dry, and moisturizers applied. The patient should be moved every 2 hours and the feet kept raised with pillows or pads. Exercises should be administered to the legs and arms to keep them flexible. Dehydration. Dehydration can become a problem. It is essential to encourage fluid intake equal to 8 glasses of water daily. Coffee and tea are diuretics and will deplete fluid. Eating Problems. Weight loss and the gradual inability to swallow are two major related problems in late-stage Alzheimer's and are associated with an increased risk of death. Weight gain, however, is linked to a lower risk of dying. The patient can be fed through a feeding syringe, or the caregiver can encourage chewing action by pushing gently on the bottom of the patient's chin and on the lips. The caregiver should offer the patient foods of different consistency and flavor. Because choking is a danger, the caregiver should learn to administer the Heimlich maneuver, which may be taught by the local American Red Cross. In very late stages, some caregivers choose feeding tubes for the patient. They should be aware that feeding tubes have no measurable impact on survival. Care for the CaregiverAbout 80% of patients with Alzheimer's disease are cared for by family members, who often lack adequate support, finances, or training for this difficult job. Few diseases disrupt patients and their families so completely or for so long a period of time as Alzheimer's. The patient's family endures two separate losses and grieves twice:
Often, caregivers themselves begin to show signs of mental disorder or ill health. Depression, empathy, exhaustion, guilt, and anger can play havoc with even a healthy individual faced with the care of a loved one suffering from Alzheimer's. Fortunately, research shows that intensive support services can greatly improve caretakers’ quality of life and make it easier for them to continue caring for patients in their homes. Such support includes individual and family counseling, telephone counseling, support groups, and stress management and problem-solving techniques. Such help may reduce the rates of depression and improve self-confidence in caregivers, and possibly enable the patient to remain in the home. Nursing Homes and Other Outside ServicesA point comes when the most devoted caregiver will probably need to institutionalize the patient. That point is determined not only by the caregiver's emotional endurance, but also by their physical strength and stamina, as a patient typically takes on the random, undisciplined behavior of a very young child. Financial considerations in finding a nursing home are often paramount, but the kind of care is equally important. Although fully half of all nursing home patients suffer from Alzheimer's, not all nursing homes have programs specifically designed for them. Some institutions may claim that they do, but often they simply group patients together without offering any special programs. If a caregiver manages to find a facility that offers good services, it may be located far from home, making visits difficult. The caregiver must then decide whether superior care at a distant institution is worth seeing the patient less frequently. When the patient's illness becomes terminal, a hospice program may be another option. Twelve Steps for Caregivers1. Although I cannot control the disease process, I need to remember I can control many aspects of how it affects my relative. 2. I need to take care of myself so that I can continue doing the things that are most important. 3. I need to simplify my lifestyle so that my time and energy are available for things that are really important at this time. 4. I need to cultivate the gift of allowing others to help me, because caring for my relative is too big a job to be done by one person. 5. I need to take one day at a time rather than worry about what may or may not happen in the future. 6. I need to structure my day because a consistent schedule makes life easier for me and my relative. 7. I need to have a sense of humor because laughter helps to put things in a more positive perspective. 8. I need to remember that my relative is not being difficult on purpose; rather their behavior and emotions are distorted by the illness. 9. I need to focus on and enjoy what my relative can still do rather than constantly lament over what is gone. 10. I need to increasingly depend upon other relationships for love and support. 11. I need to frequently remind myself that I am doing the best that I can at this very moment. 12. I need to draw upon the Higher Power, which I believe is available to me. Source: The American Journal of Alzheimer's Care and Related Disorders & Research, Nov/Dec 1989 Resources
ReferencesAD2000 Collaborative Group, Bentham P, Gray R, Sellwood E, Hills R, Crome P, Raftery J. Aspirin in Alzheimer's disease (AD2000): a randomised open-label trial. Lancet Neurol. 2008 Jan;7(1):41-9. ADAPT Research Group, Lyketsos CG, Breitner JC, Green RC, Martin BK, Meinert C, et al. Naproxen and celecoxib do not prevent AD in early results from a randomized controlled trial. Neurology. 2007 May 22;68(21):1800-8. Epub 2007 Apr 25. ADAPT Research Group, Martin BK, Szekely C, Brandt J, Piantadosi S, Breitner JC, et al. Cognitive function over time in the Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT): results of a randomized, controlled trial of naproxen and celecoxib. Arch Neurol. 2008 Jul;65(7):896-905. Epub 2008 May 12. Akomolafe A, Beiser A, Meigs JB, Au R, Green RC, Farrer LA, et al. Diabetes mellitus and risk of developing Alzheimer disease: results from the Framingham Study. Arch Neurol. 2006 Nov;63(11):1551-5. Ayalon L, Gum AM, Feliciano L, Arean PA. Effectiveness of nonpharmacological interventions for the management of neuropsychiatric symptoms in patients with dementia: a systematic review. Arch Intern Med. 2006 Nov 13;166(20):2182-8. Belle SH, Burgio L, Burns R, Coon D, Czaja SJ, Gallagher-Thompson D, et al. Enhancing the quality of life of dementia caregivers from different ethnic or racial groups: a randomized, controlled trial. Ann Intern Med. 2006 Nov 21;145(10):727-38. Cummings JL, Schneider E, Tariot PN, Graham SM; Memantine MEM-MD-02 Study Group. Behavioral effects of memantine in Alzheimer disease patients receiving donepezil treatment. Neurology. 2006 Jul 11;67(1):57-63. Durga J, van Boxtel MP, Schouten EG, Kok FJ, Jolles J, Katan MB, et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised, double blind, controlled trial. Lancet. 2007 Jan 20;369(9557):208-16. Farlow MR, Cummings JL. Effective pharmacologic management of Alzheimer's disease. Am J Med. 2007 May;120(5):388-97. Feldman HH, Ferris S, Winblad B, Sfikas N, Mancione L, He Y, et al. Effect of rivastigmine on delay to diagnosis of Alzheimer's disease from mild cognitive impairment: the InDDEx study. Lancet Neurol. 2007 Jun;6(6):501-12. Freund-Levi Y, Eriksdotter-Jonhagen M, Cederholm T, Basun H, Faxen-Irving G, et al. Omega-3 fatty acid treatment in 174 patients with mild to moderate Alzheimer disease: OmegAD study: a randomized double-blind trial. Arch Neurol. 2006 Oct;63(10):1402-8. Knopfman DS. Alzheimer’s disease and other dementias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 425. Luchsinger JA, Reitz C, Patel B, Tang MX, Manly JJ, Mayeux R. Relation of diabetes to mild cognitive impairment. Arch Neurol. 2007 Apr;64(4):570-5. McMahon JA, Green TJ, Skeaff CM, Knight RG, Mann JI, Williams SM. A controlled trial of homocysteine lowering and cognitive performance. N Engl J Med. 2006 Jun 29;354(26):2764-72. Mittelman MS, Haley WE, Clay OJ, Roth DL. Improving caregiver well-being delays nursing home placement of patients with Alzheimer disease. Neurology. 2006 Nov 14;67(9):1592-9. Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS. Associations of vegetable and fruit consumption with age-related cognitive change. Neurology. 2006 Oct 24;67(8):1370-6. Regan C, Katona C, Walker Z, Hooper J, Donovan J, Livingston G. Relationship of vascular risk to the progression of Alzheimer disease. Neurology. 2006 Oct 24;67(8):1357-62. Scarmeas N, Stern Y, Mayeux R, Luchsinger JA. Mediterranean diet, Alzheimer disease, and vascular mediation. Arch Neurol. 2006 Dec;63(12):1709-17. Epub 2006 Oct 9. Schneider JA, Arvanitakis Z, Bang W, Bennett DA. Mixed brain pathologies account for most dementia cases in community-dwelling older persons. Neurology. 2007 Jun 13; [Epub ahead of print] Small GW, Kepe V, Ercoli LM, Siddarth P, Bookheimer SY, Miller KJ, et al. PET of brain amyloid and tau in mild cognitive impairment. N Engl J Med. 2006 Dec 21;355(25):2652-63. Willis SL, Tennstedt SL, Marsiske M, Ball K, Elias J, Koepke KM, et al. Long-term effects of cognitive training on everyday functional outcomes in older adults. JAMA. 2006 Dec 20;296(23):2805-14. Wilson RS, Krueger KR, Arnold SE, Schneider JA, Kelly JF, Barnes LL, et al. Loneliness and risk of Alzheimer disease. Arch Gen Psychiatry. 2007 Feb;64(2):234-40.
Review Date:
8/9/2008 Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-
A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited. |
