Alzheimer’s and Dementia Overview
Alzheimer’s disease is a brain disorder that seriously affects a person’s ability to carry out daily activities. It is estimated that more than 5 million individuals in North America suffer from Alzheimer’s disease. Alzheimer’s disease progresses over many years from symptoms such as mild forgetfulness to more severe difficulties with memory, abstract reasoning, language, and the ability to function in general.
While increasing age is the largest risk factor for developing Alzheimer’s disease, severe memory loss is not a normal part of aging. Alzheimer’s disease is the most common form of dementia among older people. Scientists do not yet fully understand what causes Alzheimer’s disease, and there is no known cure.
What are the symptoms of Alzheimer’s disease?
Alzheimer’s disease affects the areas of the brain that are essential for thinking, memory, and behavior. With Alzheimer’s disease, motor skills (movement) often are preserved. Symptoms of Alzheimer’s disease include:
- Memory loss
- Confusion
- Restlessness
- Misplacing things
- Trouble performing familiar tasks
- Changes in personality and behavior
- Poor or decreased judgment
- Impaired communication
- Inability to follow directions
- Problems with language
- Impaired visuospatial skills
- Emotional apathy
- Social withdrawal and less willingness to interact with others
- Loss of motivation or initiative
The symptoms of Alzheimer’s disease might resemble those of other medical conditions or problems, so it is important to talk to your doctor for an accurate diagnosis.
What causes Alzheimer’s disease?
Researchers do not know the exact cause of Alzheimer's disease, but it likely is due to a variety of genetic and environmental factors. Some factors are suspected to have a role in the development of Alzheimer’s disease. They include:
- Age and family history
- Certain genes
- Abnormal protein deposits in the brain
- Certain environmental factors, such as head trauma
Brain studies show that chemical and structural changes occur in the brain tissue of people with Alzheimer’s disease. These changes interfere with a person’s ability to process, store, and retrieve information. It is not known why these changes occur.
How common is Alzheimer’s disease?
The Alzheimer’s Association estimates that one in 10 people over age 65 and nearly half of people over 85 have Alzheimer’s disease. The percentage of people who have the disease increases every decade after the age of 60.
Currently, about 4.5 million Americans suffer from Alzheimer’s disease, and about 22,000 people die from Alzheimer’s disease every year. This makes Alzheimer’s disease the seventh leading cause of death in people over 65 years old. The number of Americans with Alzheimer’s disease is expected to increase to 14 million by 2050, unless a cure or preventive measure can be found.
Other causes of dementia
Dementia can be caused by many different medical conditions, including:
- degenerative diseases, such as Alzheimer’s, Huntington’s or Parkinson’s diseases
- vascular diseases or stroke
- metabolic disorders, such as severe kidney or liver disease
- certain vitamin deficiencies
- adverse medication reactions
- drug or alcohol abuse, and
- psychiatric disorders
Some dementias respond to treatment or are reversible.
How is Alzheimer’s disease diagnosed?
There is no single test to diagnose Alzheimer’s disease. A definite diagnosis of Alzheimer’s disease depends on finding plaques and tangles in the brain after death. However, clinical criteria are commonly used to diagnose "probable" Alzheimer’s disease and are very accurate. A thorough medical evaluation is needed to identify the most likely cause of dementia.
In addition to a relevant medical history and physical examination, the tests commonly used to diagnose Alzheimer’s or to exclude other medical conditions that might worsen cognition include:
- Mental status test (questions/tests to evaluate the amount of decline in mental functioning, including orientation, memory, and language skills)
- Neuropsychological testing
- Computed tomography (CT) or magnetic resonance imaging (MRI) scan
- Blood tests (blood counts, vitamin levels, liver and kidney function, mineral balance, thyroid gland function)
Additional laboratory tests or brain imaging scans (for example, PET scan) are sometimes needed to diagnose other diseases that can cause dementia.
How is Alzheimer’s disease treated?
At this time, there is no cure for Alzheimer’s disease, no way of slowing the progression of the disease, and no treatment available to reverse its effects. New research findings give reason for hope, and several drugs are being studied in clinical trials to determine if they can slow the progress of the disease, or improve memory or other symptoms for a period of time.
There also are medicines available to assist in managing some of the most troubling symptoms of Alzheimer’s disease, including depression, behavioral problems, and sleeplessness. In managing the disease, physical exercise and social activity are important, as are proper nutrition, health maintenance, and a calm and well-structured environment.
What medicines are used to treat Alzheimer’s disease?
The medicines used to treat Alzheimer’s disease include the cholinesterase inhibitors (donepezil, rivastigmine, and galantamine), and the NMDA antagonist, memantine.
- Donepezil, rivastigmine, and galantamine work by slowing the breakdown of acetylcholine, the chemical that helps nerve cells in the brain transmit impulses. They do not cure Alzheimer’s or stop the progression of the disease, but can help relieve some memory impairment, reduce some behavioral symptoms, and improve self-care abilities compared to a placebo (dummy pill). Most people have no or only mild side effects from these medications. The most common side effects of the drugs are nausea, vomiting, and diarrhea. In some people, loss of appetite, insomnia or bad dreams, weakness, or fainting occur.
- Memantine blocks a brain receptor that is thought to enhance the cellular injury associated with Alzheimer’s disease.
Except for memantine, these medications are approved for use in mild-to-moderate Alzheimer’s disease. Memantine and donepezil are approved for moderate-to-severe.
What is the outlook for people with Alzheimer’s disease?
Alzheimer’s disease gets worse over time, and the course of the disease varies from person to person. As the dementia gradually worsens, the older person with Alzheimer’s disease will die of complications resulting from infections, poor nutrition or other medical diseases.
Can Alzheimer’s disease be prevented?
Because the exact cause of Alzheimer’s disease is unknown, there currently is no proven prevention of the disease. Although no cure for Alzheimer’s disease is available, lifestyle can help slow the worsening of symptoms and help the person’s mood and behavior.
Planning and medical/social management can help ease the burden on both patients and family members. Physical exercise, good nutrition (a well-balanced diet with adequate protein, fruits, vegetables, and fiber), and social activities (for example, socializing with family and friends, or attending day care programs) are very helpful. A calm, structured environment also might help the person with Alzheimer’s disease to continue functioning as long as possible.
What research is being done on Alzheimer’s disease?
Researchers continue to study medications to treat Alzheimer’s disease. Carefully designed and conducted studies are necessary to give a clear picture of safety and effectiveness before any approval might be considered.
An examination of the possible risk factors for Alzheimer’s—such as aging, family history, possibly significant head injury, genetic factors, and low education—lead to theories about how these risks produce plaques, tangles, and cell loss, characteristics that are common in Alzheimer’s disease. Newer therapies consider these risk factors and are looking at how to reduce brain inflammation and prevent the build-up of the plaques in the brain. Novel therapies include antioxidants, anti-inflammation drugs, vaccines targeted against the protein that results in plaques, and even genetic interventions.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional written health information, please contact the Health Information Center at the Cleveland Clinic (216) 444-3771 or toll-free (800) 223-2273 extension 43771 or visit http://my.clevelandclinic.org/health/Pages/Health_Chat.aspx. This document was last reviewed on: 8/15/2007
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