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Dementia

Definition

Dementia is a loss of mental ability severe enough to interfere with normal activities of daily living, lasting more than six months, not present since birth, and not associated with a loss or alteration of consciousness.

Description

Dementia is a group of symptoms caused by gradual death of brain cells. The loss of cognitive abilities that occurs with dementia leads to impairments in memory, reasoning, planning, and behavior. While the overwhelming number of people with dementia are elderly, it is not an inevitable part of aging. Instead, dementia is caused by specific brain diseases. Alzheimer's disease (AD) is the most common cause, followed by vascular or multi-infarct dementia.

The prevalence of dementia has been difficult to determine, partly because of differences in definition among different studies, and partly because there is some normal decline in functional ability with age. Dementia affects 5-8% of all people between ages 65 and 74, and up to 20% of those between 75 and 84. Estimates for dementia in those 85 and over range from 30-47%. Between two and four million Americans have AD; that number is expected to grow to as many as 14 million by the middle of the twenty-first century as the population ages.

The cost of dementia can be considerable. While most people with dementia are retired and do not suffer income losses from their disease, the cost of care often is enormous. Financial burdens include lost wages for family caregivers, medical supplies and drugs, and home modifications to ensure safety. Nursing home care may cost several thousand dollars a month or more. The psychological cost is not as easily quantifiable but can be even more profound. The person with dementia loses control of many of the essential features of his life and personality, and loved ones lose a family member even as they continue to cope with the burdens of increasing dependence and unpredictability.

Causes and symptoms

Causes

Dementia usually is caused by degeneration in the cerebral cortex, the part of the brain responsible for thoughts, memories, actions and personality. Death of brain cells in this region leads to the cognitive impairment that characterizes dementia.

The most common cause of dementia is AD, accounting for one-half to three-fourths of all cases. The brain of a person with AD becomes clogged with two abnormal structures, called neurofibrillary tangles and senile plaques. Neurofibrillary tangles are twisted masses of protein fibers inside nerve cells, or neurons. Senile plaques are composed of parts of neurons surrounding a group of proteins called beta-amyloid deposits. Why these structures develop is unknown. Current research indicates possible roles for inflammation, blood flow restriction, and toxic molecular fragments known as free radicals. Several genes have been associated with higher incidences of AD, although the exact role of these genes still is unknown.

Vascular dementia is estimated to cause from 5-30% of all dementias. It occurs from decrease in blood flow to the brain, most commonly due to a series of small strokes (multi-infarct dementia). Other cerebrovascular causes include: vasculitis from syphilis, Lyme disease, or systemic lupus erythematosus; subdural hematoma; and subarachnoid hemorrhage. Because of the usually sudden nature of its cause, the symptoms of vascular dementia tend to begin more abruptly than those of Alzheimer's dementia. Symptoms may progress stepwise with the occurrence of new strokes. Unlike AD, the incidence of vascular dementia is lower after age 75.

Other conditions that may cause dementia include:

Symptoms

Dementia is marked by a gradual impoverishment of thought and other mental activities. Losses eventually affect virtually every aspect of mental life. The slow progression of dementia is in contrast with delirium, which involves some of the same symptoms, but has a very rapid onset and fluctuating course with alteration in the level of consciousness. However, delirium may occur with dementia, especially since the person with dementia is more susceptible to the delirium-inducing effects of may types of drugs.

Symptoms include:

Diagnosis

Since dementia usually progresses slowly, diagnosing it in its early stages can be difficult. However, prompt intervention and treatment has been shown to help slow the effects of dementia, so early diagnosis is important. Several office visits over several months or more may be needed. Diagnosis begins with a thorough physical exam and complete medical history, usually including comments from family members or caregivers. A family history of either AD or cerebrovascular disease may provide clues to the cause of symptoms. Simple tests of mental function, including word recall, object naming, and number-symbol matching, are used to track changes in the person's cognitive ability.

Depression is common in the elderly and can be mistaken for dementia; therefore, ruling out depression is an important part of the diagnosis. Distinguishing dementia from the mild normal cognitive decline of advanced age also is critical. The medical history includes a complete listing of drugs being taken, since a number of drugs can cause dementia-like symptoms.

Determining the cause of dementia may require a variety of medical tests, chosen to match the most likely etiology. Cerebrovascular disease, hydrocephalus, and tumors may be diagnosed with x rays, CT or MRI scans, and vascular imaging studies. Blood tests may reveal nutritional deficiencies or hormone imbalances.

Treatment

Treatment of dementia begins with treatment of the underlying disease, where possible. The underlying causes of nutritional, hormonal, tumor-caused and drug-related dementias may be reversible to some extent. Treatment for stroke-related dementia begins by minimizing the risk of further strokes, through smoking cessation, aspirin therapy, and treatment of hypertension, for instance. No therapies can reverse the progression of AD. Aspirin, estrogen, vitamin E, and selegiline have been evaluated for their ability to slow the rate of progression. However, none of these have been proven effective. In fact, in 2002 and 2003, research revealed that non-steroidal anti-inflammatory agents (NSAIDs) did not help prevent AD and dementia. In the same two years, the Women's Health Initiative, a large clinical trial, was halted because of detrimental effects of combined estrogen and progestigin therapy, or hormone replacement therapy (HRT). Not only was HRT found to increase risk of breast cancer, stroke, and other heart disease, but the risk of probable dementia was twice that for women taking HRT than for those taking a placebo. Further, those taking HRT had a substantial and clinically important decline in indicators of cognitive ability. Studies still debate the effects of vitamin E on slowing the progression of moderately severe AD.

Care for a person with dementia can be difficult and complex. The patient must learn to cope with functional and cognitive limitations, while family members or other caregivers assume increasing responsibility for the person's physical needs. In progressive dementias such as AD, the person may ultimately become completely dependent. Education of the patient and family early in the disease progression can help them anticipate and plan for inevitable changes.

Symptoms of dementia may be treated with a combination of psychotherapy, environmental modifications, and medication. Drug therapy can be complicated by forgetfulness, especially if the prescribed drug must be taken several times daily.

Behavioral approaches may be used to reduce the frequency or severity of problem behaviors, such as aggression or socially inappropriate conduct. Problem behavior may be a reaction to frustration or over-stimulation; understanding and modifying the situations that trigger it can be effective. Strategies may include breaking down complex tasks, such as dressing or feeding, into simpler steps, or reducing the amount of activity in the environment to avoid confusion and agitation. Pleasurable activities, such as crafts, games, and music, can provide therapeutic stimulation and improve mood.

Modifying the environment can increase safety and comfort while decreasing agitation. Home modifications for safety include removal or lock-up of hazards such as sharp knives, dangerous chemicals, and tools. Child-proof latches or Dutch doors may be used to limit access as well. Lowering the hot water temperature to 120 °F (48.9 °C) or less reduces the risk of scalding. Bed rails and bathroom safety rails can be important safety measures, as well. Confusion may be reduced with simpler decorative schemes and presence of familiar objects. Covering or disguising doors (with a mural, for example) may reduce the tendency to wander. Positioning the bed in view of the bathroom can decrease incontinence.

Two drugs, tacrine (Cognex) and donepezil (Aricept), are commonly prescribed for AD. These drugs inhibit the breakdown of acetylcholine in the brain, prolonging its ability to conduct chemical messages between brain cells. They provide temporary improvement in cognitive functions for some patients with mild to moderate AD and help delay disease progression.

Psychotic symptoms, including paranoia, delusions, and hallucinations, may be treated with antipsychotic drugs, such as haloperidol, chlorpromazine, risperidone, and clozapine. Side effects of these drugs can be significant. Antianxiety drugs such as Valium may improve behavioral symptoms, especially agitation and anxiety, although BuSpar has fewer side effects. The anticonvulsant carbamazepine also is sometimes prescribed for agitation. Depression is treated with antidepressants, usually beginning with selective serotonin reuptake inhibitors (SSRIs) such as Prozac or Paxil, followed by monoamine oxidase inhibitors or tricyclic antidepressants. In general, medications should be administered cautiously to demented patients, in the lowest possible effective doses, to minimize side effects. Supervision of taking medications is generally required.

Long-term institutional care may be needed for the person with dementia, as profound cognitive losses often precede death by a number of years. Early planning for the financial burden of nursing home care is critical. Useful information about financial planning for long-term care is available through the Alzheimer's Association.

Family members or others caring for a person with dementia often are subject to extreme stress, and may develop feelings of anger, resentment, guilt, and hopelessness, in addition to the sorrow they feel for their loved one and for themselves. Depression is an extremely common consequence of being a full-time caregiver for a person with dementia. Support groups can be an important way to deal with the stress of caregiving. The location and contact numbers for caregiver support groups are available from the Alzheimer's Association; they may also be available through a local social service agency or the patient's physician. Medical treatment for depression may be an important adjunct to group support.

Alternative treatment

Several drugs are currently being tested for their ability to slow the progress of AD. These include acetyl-l-carnitine, which acts on the cellular energy structures known as mitochondria; propentofylline, which may aid circulation; milameline, which acts similarly to tacrine and donezepil; and ginkgo extract.

Ginkgo extract, derived from the leaves of the Ginkgo biloba tree, interferes with a circulatory protein called platelet activating factor. It also increases circulation and oxygenation to the brain. Ginkgo extract has been used for many years in China and is widely prescribed in Europe for treatment of circulatory problems. A 1997 study of patients with dementia seemed to show that gingko extract could improve their symptoms, though the study was criticized for certain flaws in its method.

Prognosis

The prognosis for dementia depends on the underlying disease. On average, people with Alzheimer's disease live eight years past their diagnosis, with a range from one to 20 years. Vascular dementia usually is progressive, with death from stroke, infection, or heart disease.

Prevention

There is no known way to prevent Alzheimer's disease, although several drugs under investigation may reduce its risk or slow its progression. The risk of developing multi-infarct dementia may be reduced by reducing the risk of stroke. Various studies continue to determine ways to lower risk of AD and dementia. For example, a 2003 study in the New England Journal of Medicine reported that people over age 75 who participated in leisure activities such as playing board games, reading, dancing, and playing musical instruments were less likely to have dementia after five years than others their age.

Key terms

Donepezil — A drug commonly prescribed for Alzheimer's disease that provides temporary improvement in cognitive functions for some patients with mild-to-moderate forms of the disease.

Ginkgo extract — Made from the leaves of the Ginkgo biloba tree, this extract, used in other countries to treat circulatory problems, may improve the symptoms of patients with dementia.

Neurofibrillary tangles — Abnormal structures, composed of twisted masses of protein fibers within nerve cells, found in the brains of people with Alzheimer's disease.

Senile plaques — Abnormal structures, composed of parts of nerve cells surrounding protein deposits, found in the brains of people with Alzheimer's disease.

Tacrine — A drug commonly prescribed for Alzheimer's disease that provides temporary improvement in cognitive functions for some patients with mild-to-moderate forms of the disease.

Resources

Periodicals

"Antioxidants Don't Prevent Dementia." JAAPA—Journal of the American Academy of Physicians Assistants, May 2003: 25.

MacReady, Norra. "Prompt Intervention May Help Slow Dementia." Clinical Psychiatry News, May 2003: 38.

"Research Breifs: Play Keeps Dementia Away." GP, June 23, 2003: 04.

"Risks of Hormone Treatment." The Lancet, May 31, 2003: 1877.

Organizations

Alzheimer's Association. 919 North Michigan Ave., Suite 1000, Chicago, IL 60611. (800) 272-3900. http://www.alz.org.

dementia /de·men·tia/ (de-men´shah) a general loss of cognitive abilities, including impairment of memory as well as one or more of the following: aphasia, apraxia, agnosia, or disturbed planning, organizing, and abstract thinking abilities. It does not include decreased cognitive functioning due to clouding of consciousness, depression, or other functional mental disorder.

Alzheimer's dementia see under disease.

dementia of the Alzheimer type dementia of insidious onset and gradually progressive course, with histopathological changes characteristic of Alzheimer's disease, categorized as early onset or late onset depending on whether or not it begins by the age of 65.

arteriosclerotic dementia multi-infarct dementia as a result of cerebral arteriosclerosis.

Binswanger's dementia see under disease.

boxer's dementia a syndrome due to cumulative cerebral injuries in boxers, with forgetfulness, slowness in thinking, dysarthric speech, and slow uncertain movements, especially of the legs.

dialysis dementia see under encephalopathy.

multi-infarct dementia vascular d.

paralytic dementia , dementia paraly´tica general paresis.

dementia prae´cox (obs.) schizophrenia.

presenile dementia that occurring in younger persons, usually age 65 or younger; since most cases are due to Alzheimer's disease, the term is sometimes used as a synonym of dementia of the Alzheimer type, early onset, and has also been used to denote Alzheimer's disease.

senile dementia that occurring in older persons, usually over the age of 65; since most cases are due to Alzheimer's disease, the term is sometimes used as a synonym of dementia of the Alzheimer type, late onset.

subcortical dementia any of a group of dementias thought to be caused by lesions particularly affecting subcortical brain structures, characterized by memory loss with slowness of information processing and of the formation of intellectual responses.

substance-induced persisting dementia that resulting from exposure to or use or abuse of a substance (e.g., alcohol, sedatives, anticonvulsants, or lead) but persisting long after exposure ends, usually with permanent and worsening deficits.

vascular dementia that with a stepwise deteriorating course and a patchy distribution of neurologic deficits caused by cerebrovascular disease.

de·men·tia (d

-m

)

Deterioration of intellectual faculties, such as memory, concentration, and judgment, resulting from an organic disease or a disorder of the brain, and often accompanied by emotional disturbance and personality changes.

dementia,

n general term for a variety of organic brain disorders characterized by a decline in mental acuity, personality deterioration, memory loss, disorientation, and stupor. Certain types of dementia may be partially or completely reversible.

dementia

(dimen´sh

),
n a progressive, organic mental disorder characterized by chronic personality disintegration, confusion, disorientation, stupor, deterioration of intellectual capacity and function, and impairment or control of memory, judgment, and impulses (e.g., senile psychosis, also associated with AIDS).