Memory loss is the inability to recall past events or knowledge. It is also called forgetfulness, amnesia, impaired memory, and loss of memory. Forgetfulness is generally mild and is experienced by almost everyone during life. Amnesia is total loss of memories, such as name and personal history.
Mild memory loss, such as the inability to recall someone's name or where an item was last placed (such as keys or eyeglasses), occurs in adults of all ages. It usually becomes more frequent as a person ages. Mild memory loss is referred to as forgetfulness. Mild cognitive impairment (MCI) or impaired memory is considered a transitional state between normal forgetfulness and severe memory loss. At least one cognitive (thinking) function, usually memory, is below normal or declining. When memory is affected, the condition is called amnesic MCI. Although some people with MCI remain stable or even improve, studies show that the majority, especially those with amnesic MCI, eventually develop dementia.
Severe memory loss is memory impairment to such a degree that it affects a person's ability to do everyday activities, such as driving, handling finances, or shopping. Severe memory loss includes dementia and Alzheimer's disease.
There is a big difference between mild and severe forgetfulness. Mild forgetfulness is more common as people age. It may take longer for older people to learn new things, remember familiar names or words, or where they last placed commonly used objects. These are usually signs of mild forgetfulness and not serious memory loss problems. The most common types of severe memory loss are dementia and Alzheimer's disease.
Dementia is a descriptive term for a collection of symptoms caused by a number of disorders affecting the brain. People with dementia have significantly impaired intellectual functioning that interferes with
|Moderate or severe memory impairment refers to four or fewer words|
recalled (out of 20) on combined immediate and delayed recall tests
among self-respondents. Self-respondents who refused either the
immediate or delayed recall test were excluded from the analysis. Proxy
respondents with an overall memory rating of “poor” were included as
having moderate or severe memory impairment .
|source: Adapted from Health and Retirement Study, Institute of|
Social Research, University of Michigan
|(Illustration by GGS Information Services. Cengage Learning,|
|85 and over||33.9%||31.2%||32.1%|
normal activities and relationships . They lose their ability to solve problems and maintain emotional control, and they may experience personality changes and behavioral problems, such as agitation, delusions, and hallucinations. While memory loss is a common symptom of dementia, memory loss by itself does not mean that a person has dementia.
Dementia is a condition almost always associated with the elderly. Doctors diagnose dementia only if two or more brain functions—such as memory and language skills—are significantly impaired without loss of consciousness. There are different types of dementia, including Alzheimer's disease (AD), Pick disease, frontal lobe dementia, multi-infarct dementia, and dementia caused by an infectious disease, usually human immunodeficiency virus (HIV). AD is the most common type of dementia.
Alzheimer's disease (AD) is an illness of the brain and is a type of dementia. AD causes changes in the brain tissue, including abnormal clumps (amyloid plaques) and tangled bundles of fibers (neurofibrillary tangles). Excessive amounts of these plaques and tangles in the brain are considered signs of AD. Onset of AD usually begins after age 60 and nearly half of people age 85 and older may be affected. Although it is not a normal part of aging, AD is a disorder that, with almost no exceptions, affects older people and progresses as the person ages. There is no cure and only limited treatments are available.
The cause of AD is unknown but it is suspected to be caused by multiple factors. In addition to formation of amyloid plaques and neurofibrillary tangles, researchers have found other brain changes in people with AD. Nerve cells die in areas of the brain that are vital to memory and other mental abilities, and connections between nerve cells are disrupted. There are lower levels of some of the chemicals in the brain that carry messages back and forth between nerve cells. AD may impair thinking and memory by disrupting these messages.
Genetics also plays a role in disease development. AD is a genetic disease, meaning it is inherited and may affect several members in a family. The extent genetic factors play in developing AD remains unclear. Some studies indicate more than half of people with AD inherited it in their genetic profile. Other studies indicate only 25% of AD cases are inherited. Non-inherited AD is referred to as sporadic Alzheimer's disease. As of 2007, researchers had discovered three genes that can cause early-onset AD when mutated, and two genes that increase the risk for late-onset AD (one of which is the SORL 1 gene).
AD often starts slowly. People with AD often blame their forgetfulness on old age. Over time, their memory problems worsen and they lose the ability to drive a car, cook a meal, or even read a newspaper. They may get lost easily and find even simple things confusing. Some people become worried, angry, or violent. At some point, people with advanced AD may need someone to take care of all their needs, including feeding, bathing, and grooming, either at home or in a nursing home.
No statistics are kept on mild memory loss since it is considered a minor inconvenience that nearly everyone experiences, especially as they grow older. The same is true for MCI, since there is no medical consensus on its definition. Accurate figures are also difficult to obtain because not everyone with a decline of memory shows symptoms.
As of 2007, the U. S. Congress' Office of Technology Assessment estimated that up to 6.8 million people in the United States had dementia, and at least 1.8 million of those were severely affected. Studies have found that almost half of all people age 85 and older have some form of dementia. Dementia usually begins after age 60, and the risk increases with age. At least 5% of men and women ages 65–74 have dementia.
The Alzheimer's Association estimates 5.1 million Americans have AD. By 2050 the number could rise to 13.2 million, according to the American Health Assistance Foundation (AHAF). The exact number is difficult to determine since AD is often misdiagnosed as another condition or is not diagnosed until the disease is in its later stages. The AHAF reports that approximately 65,800 people die from complication related to AD, and 350,000 new cases of AD are diagnosed each year in the United States. Worldwide, AHAF estimates 26 million people have AD as of 2007 and projects that number will increase to 106 million by 2050.
Causes and symptoms
Causes of memory loss besides the normal forgetfulness associated with aging include:
- side effects of medication
- dementia, Alzheimer's disease, and other degenerative nerve disorders of the brain
- trauma or injury to the head
- alcoholism and drug abuse
- brain tumors or infection
- herpes encephalitis
All forms of dementia result from the death of nerve cells and/or the loss of communication among these cells.
Mild memory loss
Without using formal tests it may be possible to get an idea of cognitive function by discussing current events with the patient. A physician may ask the person if they read the newspapers or watch the news on television. If so, the physician questions the patient about a recent news event. If the person is interested in sports or a particular sports team, questions related to the sport or team should be asked that any fan would know, such as the name of the team's manager or head coach, or the names and positions of top players.
Dementia and AD
Doctors use a number of methods to diagnose dementia and AD. Unfortunately, a definitive diagnosis of AD cannot be confirmed unless an autopsy is performed after death. Diagnosis before death is based upon observational findings of unexplained, slowly progressive dementia and brain-imaging studies that show a reduction in the size of the brain. Brain-imaging (neuroimaging) refers to the use of positron emission tomography (PET), magnetic resonance imaging (MRI), or computed topography (CT) scans. These are special types of pictures that allow the brain or other internal body structures to be visualized.
Tests that measure memory, language skills, math skills, and other abilities related to mental functioning are also used to help the physician accurately diagnose a patient's condition. For example, people with dementia or AD often show changes in executive functions (such as problem-solving), memory, and the ability to perform once-automatic tasks. Diagnosis is established after first excluding other possible causes for dementia or AD. It is important that any treatable conditions, such as depression , normal pressure hydrocephalus, or vitamin B12 deficiency, which cause similar symptoms are ruled out. Early, accurate diagnosis of dementia and AD is important for patients and their families because it allows early treatment of symptoms. For people with AD or other progressive dementias, early diagnosis may allow them to plan for the future while they can still help to make decisions. These patients also may benefit from drug treatment.
The clinical effectiveness of treating mild memory impairment where no specific medical cause has been identified, has yet to be fully tested. It is believed that these individuals might represent patients who are just beginning to develop AD and might benefit more from available treatments for AD than those patients with dementia. Besides drugs, other ways to improve memory in older adults is to learn a new skill, such as using the internet; use memory tools such as appointment calendars, to-do lists, and reminder notes; getting adequate sleep; exercising regularly; eating a healthy diet ; and restricting alcohol consumption.
There is no cure for dementia and there are no treatments that reverse or halt disease progression for most of the dementias. Patients can benefit to some extent from treatment with available medications and other measures, such as cognitive training. Many people with dementia, particularly those in the early stages, may benefit from practicing tasks designed to improve performance in specific aspects of cognitive functioning. For example, people can sometimes be taught to use memory aids, such as mnemonics, computerized recall devices, or note taking. Behavior modification—rewarding appropriate or positive behavior and ignoring inappropriate behavior—also may help control unacceptable or dangerous behaviors associated with dementia.
There is no cure for AD. However, medicines that treat the symptoms of AD are available and work best for patients in the early stage of the disease. Some medicines keep memory loss and other symptoms from getting worse for a time. Other medicines work to help people with AD sleep better or feel less worried and depressed. These medicines do not directly treat the disease, but they do help patients feel more comfortable in their surroundings.
As of 2008, there were five oral drugs approved by the U.S. Food and Drug Administration (FDA) to control the symptoms of AD and slow its progression. Four of these drugs, called cholinesterase inhibitors, slow the metabolic breakdown of acetylcholine, an important brain chemical involved in nerve cell communication. These drugs make more of this chemical available for communication between cells, which in turn slows the progression of cognitive impairment. Cholinesterase inhibitors can be effective for patients with mild to moderate symptoms of AD. These four drugs are tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne). In 2006, the FDA approved the use of donepezil to treat severe symptoms of AD and in 2007, approved rivastigmine in a patch form that delivers the drug through the skin. The fifth drug, memantine (Namenda), is approved to treat moderate to severe AD. Adverse side effects of all five drugs include nausea, dizziness , headache, and fatigue. Some of these drugs also are used to treat non-AD types of dementia.
Several studies have found that high fat and high calorie diets may increase the risk of developing AD and other types of progressive dementia. Other risk factors for dementia and AD include alcohol, salt, and refined carbohydrates . It is recommended that patients with dementia avoid environmental toxins, such as tobacco smoke.
The incidence of AD in European and North American countries has been shown to be reduced with fish consumption. Researchers speculate that Omega-3 fatty acids in fish may delay the onset of AD. Anti-inflammatory agents, such as antioxidants , have shown some effectiveness in treating dementia. A diet that includes antioxidants such as vitamin C, vitamin E , selenium, green tea, and ginkgo biloba extract, may be beneficial. Ginkgo biloba, in addition to its antioxidant properties, increases blood and oxygen flow to the brain, thereby boosting brain function.
QUESTIONS TO ASK YOUR DOCTOR
- How can I tell if I have mild or severe memory loss?
- What can I do to help improve my memory or prevent further memory loss?
- Are there tests available that can determine if I have dementia or AD?
- If I have dementia or AD, how can I expect it to progress?
- Is there anything that can be done to slow the progression?
- Are there any new or experimental treatments available or that are on the horizon?
For mild memory loss, therapy may include activities such as playing cards, board games, and word games like crossword puzzles and anagrams. Reading books, magazines, or newspapers regularly, and then discussing them with friends, relatives, or caregivers also aids memory retention.
There are no specific therapies associated with dementia or AD. A patient with these disorders is encouraged to exercise as much as their symptoms or physical limitations allow. Daily supervised walks are a good general exercise for people with severe memory impairment. Physicians recommend that people with dementia or AD try to live as normal a life as possible. This includes maintaining contact with and visiting friends and relatives, and maintaining their usual daily routines. Caregivers can assist with these recommendations.
Only about 15% of people with mild memory loss progress to dementia or AD. The other 85% continues to live a relatively normal life with memory loss causing only minimal interference in their daily lives. Patients with dementia or AD typically survive 8–10 years after diagnosis. Death is most frequently related to malnutrition , secondary infection (infection that is not the initial medical problem, such as pneumonia ) or heart disease . Malnutrition is a state in which not enough calories are taken in to support the normal functions of the human body. Malnourished people are also more prone to infections. There is no evidence that links AD to heart disease, but the rate for both increases as people age.
Restricting alcohol intake to one or two drinks a day or less, not smoking , eating a healthy diet, and exercising both mentally and physically on a regular basis can prevent or delay the onset of mild memory loss. Higher education achievement seems to reduce risk, but this may be related to people of higher education remaining more mentally active in retirement.
As of early 2008, there was no known way to prevent dementia or AD. A number of studies in laboratory mice indicate that a Mediterranean-style diet low in sugar and saturated animal fat, and high in fruits, vegetables, and whole-grains may reduce the risk of developing abnormal memory loss, including dementia. Several studies also suggest that a glass of red wine once a day may provide protection against memory loss.
Research has revealed a number of other factors that may prevent or delay the onset of memory loss some people. For example, studies have shown that people with diabetes who maintain tight control over glucose (sugar) levels in their blood tend to score better on tests of cognitive function than those with poorly controlled diabetes. Several studies also suggest that people who engage in intellectually stimulating activities, such as social interactions, chess, crossword puzzles, and playing a musical instrument significantly lower their risk of developing forms of dementia. Mental activities may stimulate the brain in a way that increases a person's cognitive reserve—the ability to cope with or compensate for the pathologic changes associated with dementia.
Caring for a person with severe memory loss at home is a difficult task and can become overwhelming. Each day brings new challenges as the caregiver copes with changing levels of ability and new patterns of behavior. Caregivers themselves often are at increased risk for depression and illness, especially if they do not receive adequate support from family, friends, and the community. A major struggle caregivers face is dealing with the difficult behaviors of the person they are caring for. Basic activities of daily living such as dressing, bathing, and eating often become difficult to manage for both the person with severe memory loss and the caregiver. Having a plan for getting through the day can help caregivers cope.
amnesic —Relating to amnesia, the loss of memory.
amyloid plaque —A waxy, translucent substance composed of complex protein fibers and polysaccharides that forms in body tissues in some degenerative diseases, such as Alzheimer's disease.
antioxidant —A substance that inhibits the destructive effects of oxidation in the body.
computed tomography (CT) scan —A diagnostic radiological scan in which cross-sectional images of the body are formed and shown on a computer screen.
delusion —A persistent false belief held in the face of strong contradictory evidence.
dementia —A usually progressive deterioration of intellectual functions, such as memory, that can occur while other brain functions such as those controlling movement and the senses are retained.
genetic disease —A disease that is inherited from one or both parents.
hydrocephalus —An increase of cerebrospinal fluid around the brain, resulting in an enlarged head.
Parkinson's disease —A progressive nervous disorder marked by symptoms of trembling hands, lifeless face, monotone voice, and a slow shuffling walk.
positron emission tomography (PET) —A method of medical imaging capable of displaying the metabolic activity of organs in the body that is useful in investigating brain disorders.
tomography —A technique of using ultrasound, gamma rays, or x rays to produce a focused image of the structures across a specific depth within the body, while blurring details at other depths.
Each person with severe memory loss is unique and responds differently. Caregivers should remain calm and offer reassurance to the person in their care. Community organizations are often available to provide assistance and support groups for caregivers can provide a place to express their feelings and help anticipate future challenges. The person with severe memory loss must be monitored closely when they are unable to determine their own care. Caregivers should learn to recognize signs that the memory loss is getting progressively worse.
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Alzheimer's Australia, P.O. Box 4019, Hawker, ACT, Australia, 2614, 612 6254 4233, (800) 100-500 (Australia only), http://www.alzheimers.org.au.
European Alzheimer's Disease Consortium, Dept. of Internal Medicine and Clinical Gerontology, Toulouse University Hospital, 170 Avenue de Casselardit, Toulouse,, France, 31300, 33-5-6177-7649, 33-5-6149 7109, [email protected], http://www.eadc.alzheimer-europe.org.
Ken R. Wells