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Definition

Dementia is a condition characterized by a progressive, irreversible decline in mental ability, accompanied by changes in behavior and personality. There is commonly a loss of memory and skills that are required to carry out activities of daily living.

Description

Dementia is a group of symptoms caused by the gradual death of brain cells. The loss of cognitive abilities that occurs with dementia leads to impairments in memory, reasoning, planning, and personality. Dementia can occur at any age and may affect younger people as the result of disease such as AIDS, hypoxia (a deficiency of oxygen reaching the tissues of the body), or injury. However, it is primarily a disease of the elderly, affecting more than 15% of those over 65 years of age, and as many as 40% of those over the age of 80. The condition is somewhat more common among women than men. Some studies suggest that the risk for dementia is higher for African Americans and Hispanic Americans than it is for Caucasians. More than half of all nursing home admissions occur because of dementia.

While the overwhelming majority of people with dementia are elderly, it is not an inevitable part of aging. One of the challenges for health care professionals is to differentiate the early-stage cognitive deficits of dementia from normal age-related memory impairment. Persons with age-related memory impairment may tend to learn new information more slowly; but, if they are given additional time, their cognitive performance is usually adequate. Other problems that may be mistakenly labeled dementia include delirium, psychosis, depression, and the side effects of various medications.

Dementia presents a major health problem for the United States because of its huge impact on individuals and their families, the health care system, and society overall. The costs of dementia are considerable. While most people with the disease are retired and do not suffer income losses, the cost of care is often 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. As of 1998, the cost of caring for Alzheimer's dementia patients alone was estimated to be slightly over $50 billion. The psychological costs are not as easily quantifiable, but can be even more profound. The person with dementia loses control of many of the essential features of 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 is usually 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. Dementia may be caused by a variety of illnesses.

The most common cause of dementia is Alzheimer's disease (AD), accounting for half to three-quarters of all cases.

Vascular dementia accounts for 5–30% of all dementias in the United States. It occurs from a 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 appear more abruptly than those of Alzheimer's dementia. Symptoms may progress with the occurrence of new strokes. Unlike AD, the incidence of vascular dementia decreases after the age of 75.

Other conditions that may cause dementia include:

• AIDS
• Parkinson's disease
• Lewy body disease
• Pick's disease
• Huntington's disease
• Creutzfeldt-Jakob disease
• brain tumors
• hydrocephalus
• head trauma
• prolonged abuse of alcohol or other drugs
• vitamin B₁₂ deficiency
• hypothyroidism
• hypercalcemia

Symptoms

Dementia is marked by a gradual decline of thought and other mental activities. The onset may be slow, occurring over months or years. 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 along with dementia, especially since the person with dementia is more susceptible to the delirium-inducing effects of many types of drugs.

Symptoms of dementia may include:

• Memory losses: Memory loss is usually the first symptom noticed. It may begin with misplacing valuables such as a wallet or car keys, then progress to situations such as forgetting appointments, where the car was left, or the route home. More profound losses follow, such as forgetting the names and faces of family members.
• Impaired abstraction and planning: The person with dementia may lose the ability to perform familiar tasks, to plan activities, and to draw simple conclusions from facts.
• Language and comprehension disturbances: The person may be unable to understand instructions, or follow the logic of moderately complex sentences. Later, the individual may not be able to understand his or her own sentences, and have difficulty forming thoughts into words.
• Poor judgment: The person may not recognize the consequences of his or her actions or be able to evaluate the appropriateness of behavior. Behavior may become ribald, overly friendly, or aggressive. Personal hygiene may be ignored.
• Impaired orientation: The person may not be able to identify the time of day, even from obvious visual clues; or may not recognize a location, even if familiar. This disability may stem partly from losses of memory and partly from impaired abstraction.
• Decreased attention and increased restlessness: These symptoms may cause the person with dementia to begin an activity and quickly lose interest, and to wander frequently. Wandering may cause significant safety problems, when combined with disorientation and memory losses. The person may begin to cook something on the stove, then become distracted and wander away while it is cooking.
• Personality changes and psychosis: The person may lose interest in once pleasurable activities, and become more passive, depressed, or anxious. Delusions, suspicion, paranoia, and hallucinations may occur later in the disease. Sleep disturbances may occur, including insomnia and sleep interruptions.

Diagnosis

Since dementia usually progresses slowly, diagnosing it in the early stages can prove difficult. However, as the elderly population grows and the prevalence of dementia increases, the importance of recognizing the early symptoms has become imperative.

Dementia may be suspected by the health care professional if memory deficits are exhibited during an examination or assessment. Information from the family members, friends, and caregivers may point to dementia as well. Diagnosis begins with a thorough physical exam and complete medical history. A family history of either Alzheimer's disease 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. If dementia is suspected, a complete review of medications and an assessment for chronic disease processes are indicated. If the patient shows no improvement after eliminating unnecessary medications and treating the chronic disease, then other tests are warranted. Physical examination and a variety of laboratory tests may rule out potentially treatable causes of dementia. These may include hearing or visual deficits, hypothyroidism, vitamin B₁₂ deficiency, and depression. Some of the laboratory tests that might be performed include a complete blood cell count and urinalysis (to rule out infection), serum electrolytes, glucose and calcium levels, and kidney and liver function tests.

The use of computed tomography (CT) or magnetic resonance imaging (MRI) to rule out vascular disease is somewhat controversial, since even if a cause is discovered, less than 11% of patients with cognitive decline have partially or fully reversible disease.

Treatment

Treatment of dementia starts 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, including smoking cessation, aspirin therapy, and treatment of hypertension. There are no known therapies that can reverse the progression of Alzheimer's disease.

Early intervention may allow the patient to compensate for the alterations in functioning, help to minimize complications, and have an improved quality of life. It may also allow the patient and family to plan for the future and to identify resources.

Periodically, new drugs are studied for the treatment of dementia. The only drugs currently approved for the symptomatic treatment of AD are tacrine (Cognex) and donepazil (Aricept). These drugs act by slowing down the degradation of neurotransmitters. They may provide temporary improvement in cognitive functioning for about 40% of patients with mild-to-moderate AD. However, drug therapy can be complicated by forgetfulness, especially if the drug must be taken several times a day.

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. Anti-anxiety drugs such as Valium may improve behavioral symptoms, especially agitation and anxiety, although BuSpar has fewer side effects. The anticonvulsant carbamazepine is also sometimes prescribed for agitation. Depression is treated with antidepressants, usually beginning with selective serotonin reuptake inhibitors (SSRIs) such as Prozac or Paxil.

In general, medications should be administered very cautiously to demented patients, in the lowest possible effective doses, to minimize side effects. Supervision of taking medications is generally required.

The primary goals of treatment for progressive dementia are to preserve as much functioning and independence as possible, and to maintain quality of life as long as possible. It is important that the patient and caregivers are aware that caring 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 may need to assume increasing responsibility for the person's physical needs. The patient and family should be educated early on in the disease progression to help them anticipate and plan for inevitable changes.

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. Childproof latches may be used to limit access as well. Bed rails and bathroom safety rails can be important safety measures. Confusion may be reduced with the use of simpler decorative schemes and the presence of familiar objects. Covering or disguising doors may reduce the tendency to wander. Positioning the bed in view of the bathroom can decrease incontinence.

Long-term institutional care may be required 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 are often subject to extreme stress, and may develop feelings of anger, resentment, guilt, and hope-lessness, 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. Contact numbers are available from the Alzheimer's Association; they may also be available through a local social service agency.

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 is usually progressive, with death resulting from stroke, infection, or heart disease.

Health care team roles

Any member of the health care team may work with patients with dementia. The physician normally makes the diagnosis. Laboratory technicians may obtain laboratory tests, and radiology technicians may perform imaging studies, if ordered. Nurses assess patients and how dementia affects their functioning. Patient education is very important in managing dementia and is a nursing responsibility.

Prevention

There is no known way to prevent AD, although several drugs under investigation may reduce its risk or slow its progression. The risk of developing multi-infarct dementia may be avoided by reducing the overall risk for strokes.

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KEY TERMS

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

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

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Deanna M. Swartout-Corbeil, R.N.