Alzheimer's disease

Alzheimer's disease is a progressive, degenerative neurological disorder, meaning that the disorder gets worse over time. Alzheimer's disease is the most common cause of dementia among people over the age of 65 and it is thought that up to 4.5 million people have Alzheimer's disease, according to the National Institutes of Health (NIH). Five percent of people aged 65 to 74 and roughly 35 to 50 percent of people aged over 85 have the disorder, according to the National Institute of Neurological Disorders and Stroke (NINDS). However, despite the high prevalence of Alzheimer's disease among elderly people, Alzheimer's disease is not a normal part of aging.

Alzheimer's disease occurs when neurons in the brain die or break their connections with other neurons. This occurs because people with Alzheimer's disease experience atrophy of a part of the brain called the hippocampus. The hippocampus produces a neurotransmitter called acetylcholine. This chemical carries electrical signals from one neuron to another and is essential for memory, judgment and learning. In people with Alzheimer's disease, the cells that produce acetylcholine are damaged or killed and levels of the chemical gradually decline in the brain. This means that the electrical signals are not transmitted effectively from one neuron to another, causing the breakdown of neuron connections and the gradual atrophy of other parts of the brain.

The symptoms of Alzheimer's disease reflect where neuron connections are broken. For example, memory loss, a common early stage symptom, is caused by the disruption of neurons in the temporal and parietal lobes, which are associated with memory. Language problems, on the other hand, are thought to be caused by the disruption of the large networks of neurons that are associated with understanding and producing language.

People with Alzheimer's disease also have abnormal lesions called beta-amyloid plaques and neurofibrillary tangles. Beta-amyloid plaques are sticky pieces of protein and other matter than surround the neurons. Neurofibrillary tangles are twisted fibers also made from protein that build up inside the neurons. These plaques and tangles work together to disrupt brain function and are known to increase in quantity as the Alzheimer's disease progresses.

Certain factors of brain dysfunction in Alzheimer's disease are known, but much about the disease is unknown. The known factors include the onset and progress of dementia in patients and the presence of the plaques and tangles in their brains, which may be detected at autopsy. But specific causes remain unknown and the role of plaques and tangles, as either cause or result, are not well understood. It is thought that these amyloid plaques form very early in the disease stage and set of a cascade of inflammation and cell death throughout the affected portions of the brain. However, no one knows why the amyloid plaques form. Similarly, very little is understood about the tangles in the brain, or how they relate to the plaques.

The symptoms of Alzheimer's disease usually begin to appear around the age of 60. However, some people develop a condition called early-onset Alzheimer's disease as early as their 20s. Early-onset Alzheimer's disease is thought to be caused by a genetic disorder.

Alzheimer's disease can progress slowly or rapidly, depending on the individual. Patients generally live for an average of eight years after they are diagnosed with Alzheimer's disease, although they may live for up to 20 years. During the final stages of the disease, most patients require constant supervision and help performing basic self-care tasks such as bathing and feeding.

Most people do not die as a direct result of Alzheimer's disease. Instead, people with Alzheimer's disease are more likely to contract other medical conditions that can be fatal. Many people with Alzheimer's disease die from aspiration pneumonia (pneumonia caused by breathing in vomit or other fluids) because of the reduced ability to swallow in the later stages of the disease. In 2004, the most recent year for which figures are available, Alzheimer's disease was the fifth leading cause of death among people over 65 and the seventh leading cause of death overall, according to the Centers for Disease Control and Prevention (CDC).

Women are more commonly diagnosed with Alzheimer's disease than men, although this may be because women tend to live longer than men.

Although Alzheimer's disease is the leading cause of dementia, other conditions may cause dementia, including stroke, brain tumors and infections.

Alzheimer’s disease is caused by the progressive destruction of neurons in the brain. However, physicians may refer to “stages” of Alzheimer's disease when diagnosing or monitoring the progress of the disease in a patient. These stages are commonly accepted patterns of progression that physicians have witnessed in people with the disease. However, it is important to remember that the stages are used as a rough approximation of the progress of the disease and that different staging frameworks may be used by different physicians. An example of a staging framework may be:

Although scientists are unsure of the initial cause of Alzheimer's disease, it is known that the symptoms of Alzheimer's disease are caused by the disconnection and death of neurons in the brain. Based on what scientists understand about Alzheimer's disease, the following have been established as risk factors for the disease:

Symptoms of Alzheimer's disease usually begin to appear around the age of 60. Alzheimer's disease is primarily marked by the onset and progression of dementia, a decline in mental function that may interfere with the ability to perform daily functions. Dementia involves both cognitive (intellectual) and psychiatric symptoms. Cognitive symptoms of Alzheimer's disease may include:

There is no definitive diagnostic test for Alzheimer's disease and diagnosis can often be delayed because the early symptoms (e.g., forgetfulness, mild confusion) may be similar to some of the signs of normal aging. It may be especially difficult to obtain a diagnosis if the patient is under 65 and experiencing early-onset Alzheimer's disease because early symptoms may be similar to those experienced by people under extreme stress or people who are depressed. An important aspect for physicians is to assess whether the symptoms the patient is experiencing could be due to another cause, such as vitamin deficiency, dehydration or a side effect of medication the patient is taking. Patients may be referred to a neurologist, psychiatrist or psychologist following the presentation of symptoms.

If a physician suspects Alzheimer's disease, diagnosis will begin with a physical examination and a medical history. Patients or their caregivers are encouraged to keep a log of symptoms to report to the physician. A physician may also ask family members or close friends about the nature of the patient’s symptoms. During the medical history, the physician may ask questions related to the patient’s dietary habits and use of alcohol and/or drugs in order to rule out other potential causes of dementia. During the physical examination, the physician may assess neurological function by testing the patient’s reflexes, balance and coordination.

A physician may also use an electroencephalogram (EEG). An EEG is a test in which electrodes are placed on a patient’s head and information about the brain’s electrical activity is recorded as a series of brain waves. This type of test can be used to rule out other causes of dementia, such as infections or metabolic problems.

A physician may conduct a mental status examination to assess the stage of dementia that a patient may have reached. During the exam, the physician may ask the patient a variety of questions aimed at testing the patient’s awareness of surroundings, problem solving skills and memory skills.

At this time, there is no cure for Alzheimer's disease, nor is there any way of slowing the progress of the disease. However, there are treatment options available that can minimize or stabilize patients’ symptoms, and in some cases delay the necessity of nursing home care.

A physician may prescribe medication for cognitive symptoms (e.g., memory loss, loss of language function). Some Alzheimer's medications are designed to maintain the levels of a brain chemical called acetylcholine. Acetylcholine is a neurotransmitter, which means that it carries electrical signals from one neuron to another. This chemical is essential for memory, judgment and learning. Medications that delay the breakdown of acetylcholine are called cholinesterase inhibitors. These medications may not be as effective among patients with advanced disease. Other Alzheimer's medications regulate the function of another neurotransmitter, glutamate, which is important for learning and memory. Studies have shown that these two medications — the cholinesterase inhibitors combined with glutamate receptor blockers — may be more effective than either medication used alone with severe disease.

It is thought that Alzheimer's disease may be caused or exacerbated by the presence of free radicals, a type of molecule that can damage cells and has been known to cause cancer and other medical conditions. Some physicians might recommend vitamin E, an antioxidant, used in combination with other antioxidants to reduce oxidative damage to the brain.

Behavioral or psychiatric symptoms may first be treated with methods other than medications. This usually includes identifying the potential trigger for the symptoms and attempting to resolve it. Many times this involves making adjustments to the environment that the patient lives in, for example simplifying the environment or increasing the time between stimulating events (e.g., bath-time, getting dressed). A few studies have also examined the use of aromatherapy to reduce agitation and dementia. Other possible interventions include massage therapy, exercise, and even pet therapy.

In addition to non-drug methods, a physician may recommend certain medications to control behavioral or psychiatric symptoms. It is important that these medications be used with caution because people with dementia are more likely to experience severe side effects than most people.

There is much that is unknown about Alzheimer's disease, including the cause or causes and how to slow or stop its progress. Because of this, Alzheimer's disease is a difficult disease to prevent.

There is some evidence that indicates that people who sustain severe head injuries are more likely to develop Alzheimer's disease later in life. For this reason, it is important to always wear a seatbelt while traveling in a car and to wear protective headgear while operating a motorcycle or bicycle, or while playing contact sports.

Other studies have shown that oxidative stress, the process of cell damage by free radicals, contributes to the risk of developing Alzheimer's disease. Oxidative stress can be prevented by consuming foods that are high in antioxidants, such as olive oil, fish and fresh fruit and vegetables. It can also be prevented by taking supplements of vitamin A, C and E, although a physician should always be consulted before starting any supplements.

It is also becoming clear that maintaining brain health by remaining physically and mentally active throughout life, especially in later life, is important. This includes controlling weight, blood pressure and cholesterol levels. It is not known whether physical and mental activity directly reduce the risk of developing Alzheimer's disease, but scientists agree that it appears reasonable that keeping the body and mind healthy is beneficial on many levels.

Alzheimer's disease can be overwhelming for both the patient and the patient’s loved ones. In the early stages of Alzheimer's disease, patients and their loved ones may become frustrated with memory loss or the inability to complete simple tasks. This may result in depression or anger. As the disease progresses, patients usually experience more substantial dementia that may affect their ability to perform self-care tasks such as bathing and dressing and may require professional care in a nursing home.

Alzheimer's disease also presents certain safety issues. For example, people with Alzheimer's disease are more likely to be injured around the home. Injuries may be caused by falls that occur when the parts of the brain responsible for balance and coordination are affected. Additionally, the memory loss that is associated with Alzheimer's disease may make it unsafe for patients to cook (especially over a direct heat source), drive and otherwise live independently. It may be necessary to take certain safety precautions in the home, such as installing railings around the bath or shower and setting the water temperature to a lower level to avoid scalding.

Family support is an essential aspect of Alzheimer's care and treatment. It is important that loved ones understand the patient’s limitations and adjust their behavior and communication strategies accordingly. As the disease progresses, patients may exhibit strange behavior such as aggression or forgetting the names of immediate relatives. This can be a traumatic experience for close friends and family. In some cases, individual or group therapy is beneficial for those coping with the consequences of Alzheimer's disease in a close friend or family member.