Dementia Overview

Dementia is a decline of reasoning, memory, and other mental abilities (the cognitive functions). This decline eventually impairs the ability to carry out everyday activities such as driving; household chores; and even personal care such as bathing, dressing, and feeding (often called activities of daily living, or ADLs).

Dementia is most common in elderly people; it used to be called senility and was considered a normal part of aging. We now know that dementia is not a normal part of aging but is caused by a number of underlying medical conditions that can occur in both elderly and younger persons. In some cases, dementia can be reversed with proper medical treatment. In others, it is permanent and usually gets worse over time.

About 4-5 million people in the United States have some degree of dementia, and that number will increase over the next few decades with the aging of the population. Dementia affects about 1% of people aged 60-64 years and as many as 30-50% of people older than 85 years. It is the leading reason for placing elderly people in institutions such as nursing homes. Dementia is a very serious condition that results in significant financial and human costs. Many people with dementia eventually become totally dependent on others for their care. Although people with dementia typically remain fully conscious, the loss of short and long-term memory are universal. People with dementia also experience declines in any or all areas of intellectual functioning, for example, use of language and numbers; awareness of what is going on around him or her; judgment; and the ability to reason, solve problems, and think abstractly. These losses not only impair a person’s ability to function independently, but also have a negative impact on quality of life and relationships.

Many older people fear that they are developing dementia because they cannot find their glasses or remember someone's name. These very common problems are most often due to a much less serious condition involving slowing of mental processes with age. Medical professionals call this “benign senescent forgetfulness,” or “age-related memory loss.” Although this condition is a nuisance, it does not impair a person’s ability to learn new information, solve problems, or carry out everyday activities, as dementia does

Dementia Causes

Dementia has many different causes, some of which are difficult to tell apart. Many medical conditions can cause dementia symptoms, especially in older people. The causes of dementia include various diseases and infections, strokes, head injuries, drugs, and nutritional deficiencies.

All dementias reflect dysfunction in the cerebral cortex, or brain tissue. Some disease processes damage the cortex directly; others disrupt sub-cortical areas that normally regulate the function of the cortex. When the underlying process does not permanently damage the cortical tissue, the dementia may sometimes be stopped or reversed. In classifying dementias, medical professionals may either separate cortical or sub cortical dementias or divide reversible and irreversible dementias.

Irreversible causes

The main irreversible causes of dementia are described here. These damage brain cells in both cortical and sub-cortical areas. Treatment focuses on slowing progress of the underlying condition and relieving symptoms.

Alzheimer disease. This is the most common cause of dementia, accounting for about half of all cases. Alzheimer disease is at least partly hereditary in that it tends to run in families. (Just because a relative has Alzheimer disease, however, does not mean that another family member will have the disease.) In this disease, abnormal protein deposits in the brain destroy cells in the areas of the brain that control memory and mental functions. People with Alzheimer disease also have lower-than-normal levels of brain chemicals called neurotransmitters that control important brain functions. Alzheimer disease is not reversible, and no known cure exists. However, certain medications can slow its progress.

Vascular dementia. This is the second most common cause of dementia, accounting for as many as 40% of cases. This dementia is caused by atherosclerosis, or “hardening of the arteries,” in the brain. Deposits of fats, dead cells, and other debris form on the inside of arteries, partially (or completely) blocking blood flow. These blockages cause multiple strokes, or interruptions of blood flow, to the brain. Because this interruption of blood flow is also called “infarction,” this type of dementia is sometimes called multi-infarct dementia. One subtype whose origin is not well understood is Binswanger disease. Vascular dementia is related to high blood pressure, high cholesterol, heart disease, diabetes, and related conditions. Treating those conditions can slow the progress of vascular dementia, but functions do not come back once they are lost.

Parkinson disease. People with this disease typically have limb stiffness (which causes them to shuffle when they walk), speech problems, and tremor (shaking at rest). Dementia may develop late in the disease, but not everyone with Parkinson disease has dementia. Reasoning, memory, speech, and judgment are most likely to be affected.

Lewy body dementia: This is caused by abnormal microscopic deposits of protein, called Lewy bodies, which destroy nerve cells. These deposits can cause symptoms typical of Parkinson disease, such as tremor and muscle rigidity, as well as dementia similar to that of Alzheimer disease. Lewy body dementia affects thinking, attention, and concentration more than memory and language. Like Alzheimer disease, Lewy body dementia is not reversible and has no known cure. The drugs used to treat Alzheimer disease also benefit some people with Lewy body disease.

Huntington disease: This inherited disease causes wasting of certain types of brain cells that control movement as well as thinking. Dementia is common and occurs in the late stages of the disease. Personality changes are typical. Reasoning, memory, speech, and judgment may also be affected.

Creutzfeldt-Jakob disease: This rare disease occurs most often in young and middle-aged adults. Infectious agents called prions invade and kill brain cells, leading to behavior changes and memory loss. The disease progresses rapidly and is fatal.

Pick disease (front temporal dementia): This is another rare disorder that damages cells in the front part of the brain. Behavior and personality changes usually precede memory loss and language problems.

Parkinson disease and Huntington disease begin in sub cortical areas. They cause the sub cortical type of dementia.

Treatable conditions

The dementia in these conditions may be reversible or partially reversible, even if the underlying disease or damage is not. Head injury: This refers to brain damage from accidents, such as motor vehicle wrecks and falls; from assaults, such as gunshot wounds or beatings; or from activities such as boxing without protective gear. The resulting damage of brain cells can lead to dementia.

Infections: Infections of brain structures, such as meningitis and encephalitis, are primary causes of dementia. Other infections, such as HIV/AIDS and syphilis, can affect the brain in later stages. In all cases, inflammation in the brain damages cells.

Normal pressure hydrocephalus: The brain floats in a clear fluid called cerebrospinal fluid. This fluid also fills internal spaces in the brain called cerebral ventricles. If too much fluid collects outside the brain, it causes hydrocephalus. This condition raises the fluid pressure inside the skull and compresses brain tissue from outside. It may cause severe damage and death. If fluid builds up in the ventricles, the fluid pressure remains normal (“normal pressure hydrocephalus”), but brain tissue is compressed from within.

Simple hydrocephalus: Simple hydrocephalus may cause typical dementia symptoms or lead to coma. In normal pressure hydrocephalus, people have trouble walking and become incontinent (unable to control urination) at the same time they start to lose mental functions, such as memory. If normal pressure hydrocephalus is diagnosed early, the internal fluid pressure may be lowerable by putting in a shunt. This can stop the dementia, the gait problems, and the incontinence from getting worse.

Brain tumors: Tumors can cause dementia symptoms in a number of ways. A tumor can press on structures such as the hypothalamus or pituitary gland, which control hormone secretion. They can also press directly on brain cells, damaging them. Treating the tumor, either medically or surgically, can reverse the symptoms in some cases.

Toxic exposure: People who work around solvents or heavy metal dust and fumes (lead especially) without adequate protective equipment may develop dementia from the damage these substances can cause to brain cells. Some exposures can be treated, and avoiding further exposure can prevent further damage.

Metabolic disorders: Diseases of the liver, pancreas or kidneys can lead to dementia by disrupting the balances of salts and other chemicals in the blood. Often, these changes occur rapidly and affect the person’s level of consciousness. This is called delirium. Although the person with delirium, like the person with dementia, cannot think well or remember, treatment of the underlying disease may fully reverse the condition. If the underlying disease persists, however, brain cells may die, and the person will have dementia.

Hormone disorders: Disorders of hormone-secreting and hormone-regulating organs such as the thyroid gland, the parathyroid glands, the pituitary gland, or the adrenal glands can lead to hormone imbalances, which can cause dementia if not corrected.

Poor oxygenation (hypoxia): People who do not have enough oxygen in their blood may develop dementia because the blood brings oxygen to the brain cells, and brains cells need oxygen to live. The most common causes of hypoxia are lung diseases such as emphysema or pneumonia. These limit oxygen intake or transfer of oxygen from the airways of the lungs to the blood. Cigarette smoking is a frequent cause of emphysema. It can worsen hypoxic brain damage by damaging the lungs and also by increasing the levels of carbon monoxide in the blood. Heart disease leading to congestive heart failure may also lower the amount of oxygen in the blood. Sudden, severe hypoxia may also cause brain damage and symptoms of dementia. Sudden hypoxia may occur if someone is comatose or has to be resuscitated.

Drug reactions, overuse, or abuse: Some drugs can cause temporary problems with memory and concentration as side effects in elderly people. Misuse of prescription drugs over time, whether intentional or accidental, can cause dementia. The most common culprits are sleeping pills and tranquilizers. Other drugs that cause dry mouth, constipation, and sedation (“anticholinergic side effects”) may cause dementia or dementia symptoms. Illegal drugs, especially cocaine (which affects circulation and may cause small strokes) and heroin (which is very anticholinergic) may also cause dementia, especially in high doses, if taken for long periods, or in older people. The withdrawal of the drug usually reverses the symptoms.

Nutritional deficiencies: Deficiencies of certain nutrients, especially B vitamins, can cause dementia if not corrected.

Chronic alcoholism: Dementia in people with chronic alcoholism is believed to result from other complications such as liver disease and nutritional deficiencies.

Dementia Symptoms

Symptoms of dementia vary considerably by the individual and the underlying cause of the dementia. Most people affected by dementia have some (but not all) of these symptoms. The symptoms may be very obvious, or they may be very subtle and go unrecognized for some time. The first sign of dementia is usually loss of short-term memory. The person repeats what he just said or forgets where she put an object just a few minutes ago. Other symptoms and signs are as follows:

Early dementia

• Word-finding difficulty - May be able to compensate by using synonyms or defining the word

• Forgetting names, appointments, or whether or not the person has done something; losing things

• Difficulty performing familiar tasks – Driving, cooking a meal, household chores, managing personal finances

• Personality changes (for example, sociable person becomes withdrawn or a quiet person is coarse and silly)

• Uncharacteristic behavior

• Mood swings, often with brief periods of anger or rage

• Behavior disorders – Paranoia and suspiciousness

• Decline in level of functioning but able to follow established routines at home

• Confusion, disorientation in unfamiliar surroundings – May wander, trying to return to familiar surroundings

Intermediate dementia

• Worsening of symptoms seen in early dementia, with less ability to compensate

• Unable to carry out activities of daily living (eg, bathing, dressing, grooming, feeding, using the toilet) without help

• Disrupted sleep (often napping in the daytime, up at night)

• Unable to learn new information

• Increasing disorientation and confusion even in familiar surroundings

• Greater risk of falls and accidents due to poor judgment and confusion

• Behavior disorders – Paranoid delusions, aggressiveness, agitation, inappropriate sexual behavior

• Hallucinations

• Confabulation (believing the person has done or experienced things that never happened)

• Inattention, poor concentration, loss of interest in the outside world

• Abnormal moods (anxiety, depression)

Severe dementia

• Worsening of symptoms seen in early and intermediate dementia

• Complete dependence on others for activities of daily living

• May be unable to walk or move from place to place unassisted

• Impairment of other movements such as swallowing – Increases risk of malnutrition, choking, and aspiration (inhaling foods and beverages, saliva, or mucus into lungs)

• Complete loss of short- and long-term memory – May be unable to recognize even close relatives and friends

• Complications – Dehydration, malnutrition, problems with bladder control, infections, aspiration, seizures, pressure sores, injuries from accidents or falls. The person may not be aware of these problems, especially the behavior problems. This is especially true in the later stages of dementia.

Depression in elderly people can cause dementia like symptoms. As many as 40% of people with dementia are also depressed. Common symptoms of depression include depressed mood, loss of interest in activities once enjoyed, withdrawal from others, sleep disturbances, weight gain or loss, suicidal thoughts, feelings of worthlessness, and loss of ability to think clearly or concentrate.

People with irreversible or untreated dementia present a slow, gradual decline in mental functions and movements over several years. Total dependence and death, often from infection, are the last stages.

Self-Care at Home

Many individuals with dementia in the early and intermediate stages are able to live independently.

• With regular checks by a local relative or friend, they are able to live without constant supervision.

• Those who have difficulty with activities of daily living require at least part-time help from a family caregiver or home health aide.

• Visiting nurses can make sure that these individuals take their medications as directed.

• Housekeeping help is available for those who cannot keep up with household chores. Other affected individuals require closer supervision or more constant assistance.

• Round-the-clock help in the home is available, but it is too expensive for many.

• Individuals who require this level of assistance may need to move from their home to the home of a family caregiver or to an assisted-living facility.

• Many families prefer these options because they give the individual the greatest possible independence and quality of life. For individuals who are able to remain at home or to retain some degree of independent living, maintaining a familiar and safe environment is important.

• The individual must be comfortable and safe if he or she is to continue to function independently.

• Minor modifications of the home may be needed. Most important is to prevent falls and accidents. Getting rid of area rugs and putting grab bars in the shower and mats in the tub are easy important steps to make the environment safe. Sometimes, disabling the stove or using child proof knobs may be necessary to prevent cooking accidents.

The balance between safety and independence must be assessed often. If necessary, changes must be made to keep the individual safe.

Individuals with dementia should remain physically, mentally, and socially active.

• Daily physical exercise helps the body and mind function and maintains a healthy weight. Exercise can be as simple as a daily walk.

• The individual should engage in as much mental activity as he or she can handle. Mental activity is believed to slow the progress of some types of dementia. Puzzles, games, reading, and safe hobbies and crafts are good choices.

• Social interaction is stimulating and enjoyable for most people with dementia. Most senior centers or community centers have scheduled activities, such as parties and clubs, that are suitable for those with dementia.

• A balanced diet that includes low-fat protein foods and plenty of fruits and vegetables helps maintain a healthy weight and prevent malnutrition and constipation. An individual with dementia should not smoke, both for health and safety reasons.