An Introduction to Dementia
Dementia is not a specific disease. Dementia is a descriptive term for a collection of symptoms (such as personality changes, behavioral problems, and memory problems) that can be caused by a number of conditions that affect the brain. All forms of dementia result from the death of nerve cells or the loss of communication among these cells.
Although
Alzheimer's disease and certain other conditions are technically causes of dementia, they are also often referred to as types of dementia. Likewise, terms such as "vascular dementia" are often used to describe causes as well as types of dementia.
Dementia Causes
The human brain is very complex and many factors can interfere with its functioning. Although
dementia research scientists have uncovered many of these factors, they have not yet been able to fit these puzzle pieces together in order to form a complete picture of how dementias develop.
There are many possible causes of dementia. The most common cause of dementia is
Alzheimer's disease. Over 50 percent of people diagnosed with dementia have Alzheimer's disease. Other dementia causes can include:
Other conditions that can also cause dementia or dementia-like symptoms include:
- Reactions to medications
- Metabolic problems, such as hypothyroidism
- Nutritional deficiencies, such as vitamin B12 deficiency
- Infections, including HIV/AIDS
- Poisoning
- Brain tumor or brain cancer
- Heart and lung problems
- Anoxia or hypoxia (conditions in which the brain's oxygen supply is either reduced or cut off entirely).
Although dementia is common in very elderly individuals, it is not a normal part of the aging process. Dementia can also occur in children (
see Childhood Dementia).
People with dementia have significantly impaired intellectual functioning that interferes with normal activities and relationships. People with dementia symptoms may:
- Lose their ability to solve problems and maintain emotional control.
- Experience personality changes and behavioral problems, such as agitation, delusions, and hallucinations.
- Experience memory loss. However, memory loss by itself does not mean that a person has dementia.
Doctors will make a dementia diagnosis only if two or more brain functions -- such as memory and language skills -- are significantly impaired without loss of consciousness.
Doctors employ a number of strategies to make a dementia diagnosis. They usually begin by asking a number of questions. This is typically followed by a physical exam and then certain tests and procedures. Tests that are helpful for diagnosing dementia include:
- Cognitive and neuropsychological tests
- Brain scans (MRI or CT scan)
- Laboratory tests
- Psychiatric evaluations
- Pre-symptomatic testing.
About 10 percent of dementia causes are treatable conditions, meaning that the progression of dementia can be reversed or at least stopped with early dementia treatment. For the rest, there are no known treatment options available that can stop the progression of dementia symptoms.
Drugs that are specifically used to treat
Alzheimer's disease and other progressive dementias are now available. Although these drugs do not halt dementia or reverse existing brain damage, they can improve symptoms and slow the progression of the disease. Medications that are used for the treatment of dementia can:
- Improve an individual's quality of life
- Ease the burden on caregivers
- Delay admission to a nursing home.
Many researchers are also examining whether these drugs may be useful for treating other types of dementia.
Many people with dementia, particularly those in the early stages, may benefit from practicing tasks that are designed to improve performance in specific aspects of cognitive functioning. For example, people with dementia can sometimes be taught to use memory aids, such as mnemonics, computerized recall devices, or note taking.
(Click Dementia Treatment for more information about the treatment options for people with dementia.)
Prognosis for People With Dementia
There are many disorders that can cause dementia. Some disorders, such as
Alzheimer's disease or
Huntington's disease, lead to a progressive loss of mental functions. However, other types of dementia can be halted or reversed with appropriate treatment.
People with moderate or advanced dementia typically need round-the-clock care and supervision to prevent them from harming themselves or others. They may also need assistance with daily activities such as eating, bathing, and dressing
(see Dementia Care).
The U.S. Congress Office of Technology Assessment estimates that as many as 6.8 million people in the United States have dementia, and at least 1.8 million of those are severely affected. Studies in some communities have found that almost half of all people who are 85 years of age and older have some form of dementia. Although dementia is common in very elderly individuals, it is not a normal part of the aging process. Many people live into their 90s and even 100s without any
symptoms of dementia.
What Conditions Are Not Dementia?
Conditions that are not considered dementia include:
- Age-related cognitive decline
- Mild cognitive impairment
- Depression
- Delirium.
Age-Related Cognitive Decline
As people age, they usually experience slower information processing and mild memory impairment. In addition, their brains frequently decrease in volume and some nerve cells, or neurons, are lost. These changes, called age-related cognitive decline, are normal and are not considered to be signs of dementia.
Mild Cognitive Impairment
Some people develop cognitive and memory problems that are not severe enough to be diagnosed as dementia but are more pronounced than the cognitive changes associated with normal aging. This condition is called mild cognitive impairment. Although many patients with this condition later develop dementia, some do not. Many researchers are studying mild cognitive impairment to find ways to treat it or prevent it from progressing to dementia.
Depression
People with depression are frequently passive or unresponsive, and they may appear slow, confused, or forgetful. Other emotional problems can also cause symptoms that may mimic dementia.
Delirium
Delirium is characterized by confusion and rapidly altering mental states. Delirium may also cause people to become:
- Disoriented
- Drowsy
- Incoherent.
People with delirium may also exhibit personality changes. Delirium is usually caused by a treatable physical or psychiatric illness, such as poisoning or infections. Patients with delirium often, though not always, make a full recovery after their underlying illness is treated.
Some of these dementia prevention strategies include:
- Knowing your dementia risk factors (see Dementia Risk Factors)
- Monitoring your health and making lifestyle changes
- Stimulating your brain.
Other factors that may play a role in preventing dementia include:
- Your education level
- Reducing inflammation and using nonsteroidal anti-inflammatory drugs (NSAIDs).
(Click Dementia Prevention to learn about strategies that may be helpful in preventing dementia.)
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