Dementia is a loss of brain function that occurs with certain diseases. It affects memory, thinking, language, judgment, and behavior.
See also: Alzheimer's disease
Chronic brain syndrome; Lewy body dementia; DLB; Vascular dementia; Mild cognitive impairment; MCI
Causes, incidence, and risk factors
Most types of dementia are nonreversible (degenerative). Nonreversible means the changes in the brain that are causing the dementia cannot be stopped or turned back. Alzheimer's disease is the most common type of dementia.
Lewy body disease is a leading cause of dementia in elderly adults. People with this condition have abnormal protein structures in certain areas of the brain.
Dementia also can be due to many small strokes. This is called vascular dementia.
The following medical conditions also can lead to dementia:
- Parkinson's disease
- Multiple sclerosis
- Huntington's disease
- Pick's disease
- Progressive supranuclear palsy
- Infections that can affect the brain, such as HIV/AIDS and Lyme disease
Some causes of dementia may be stopped or reversed if they are found soon enough, including:
- Brain tumors
- Changes in blood sugar, sodium, and calcium levels (see: Dementia due to metabolic causes)
- Low vitamin B12 levels
- Normal pressure hydrocephalus
- Use of certain medications, including cimetadine and some cholesterol-lowering medications
- Chronic alcohol abuse
Dementia usually occurs in older age. It is rare in people under age 60. The risk for dementia increases as a person gets older.
Dementia symptoms include difficulty with many areas of mental function, including:
- Emotional behavior or personality
- Cognitive skills (such as calculation, abstract thinking, or judgment)
Dementia usually first appears as forgetfulness.
Mild cognitive impairment is the stage between normal forgetfulness due to aging and the development of dementia. People with MCI have mild problems with thinking and memory that do not interfere with everyday activities. They are often aware of the forgetfulness. Not everyone with MCI develops dementia.
Symptoms of MCI include:
- Forgetting recent events or conversations
- Difficulty performing more than one task at a time
- Difficulty solving problems
- Taking longer to perform more difficult mental activities
The early symptoms of dementia can include:
- Language problems, such as trouble finding the name of familiar objects
- Misplacing items
- Getting lost on familiar routes
- Personality changes and loss of social skills
- Losing interest in things you previously enjoyed, flat mood
- Difficulty performing tasks that take some thought, but that used to come easily, such as balancing a checkbook, playing games (such as bridge), and learning new information or routines
As the dementia becomes worse, symptoms are more obvious and interfere with the ability to take care of yourself. The symptoms may include:
- Forgetting details about current events
- Forgetting events in your own life history, losing awareness of who you are
- Change in sleep patterns, often waking up at night
- More difficulty reading or writing
- Poor judgment and loss of ability to recognize danger
- Using the wrong word, not pronouncing words correctly, speaking in confusing sentences
- Withdrawing from social contact
- Having hallucinations, arguments, striking out, and violent behavior
- Having delusions, depression, agitation
- Difficulty doing basic tasks, such as preparing meals, choosing proper clothing, or driving
People with severe dementia can no longer:
- Understand language
- Recognize family members
- Perform basic activities of daily living, such as eating, dressing, and bathing
Other symptoms that may occur with dementia:
- Swallowing problems
Signs and tests
Dementia can often be diagnosed with a history and physical exam by a skilled doctor or nurse. A health care provider will take a history, do a physical exam (including a neurological exam), and perform some tests of mental function called a mental status examination.
The health care provider may order tests to help determine whether other problems could be causing dementia or making it worse. These conditions include:
- Thyroid disease
- Vitamin deficiency
- Brain tumor
- Intoxication from medications
- Chronic infection
- Severe depression
The following tests and procedures may be done:
- B12 level
- Blood ammonia levels
- Blood chemistry (chem-20)
- Blood gas analysis
- Cerebrospinal fluid (CSF) analysis
- Drug or alcohol levels (toxicology screen)
- Tests for exposure to metals such as lead or arsenic
- Electroencephalograph (EEG)
- Glucose test
- Head CT
- Liver function tests
- Mental status test
- MRI of head
- Serum calcium
- Serum electrolytes
- Thyroid function tests
- Thyroid stimulating hormone level
For information on how to take care of a loved one with dementia, see: Dementia - home care
The goal of treatment is to control the symptoms of dementia. Treatment depends on the condition causing the dementia. Some people may need to stay in the hospital for a short time.
Stopping or changing medications that make confusion worse may improve brain function.
There is growing evidence that some kinds of mental exercises can help dementia.
Treating conditions that can lead to confusion often greatly improve mental functioning. Such conditions include:
- Decreased oxygen (hypoxia)
- Heart failure
- Nutritional disorders
- Thyroid disorders
Medications may be needed to control behavior problems caused by a loss of judgement, increased impulsivity, and confusion. Possible medications include:
- Antipsychotics (haloperidol, risperdal, olanzapine)
- Mood stabilizers (fluoxetine, imipramine, citalopram)
- Serotonin-affecting drugs (trazodone, buspirone)
- Stimulants (methylphenidate)
Certain drugs may be used to slow the rate at which symptoms worsen. The benefit from these drugs is often small, and patients and their families may not always notice much of a change.
- Donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne, formerly called Reminyl)
- Memantine (Namenda)
A person's eyes and ears should be checked regularly. Hearing aids, glasses, or cataract surgery may be needed.
Psychotherapy or group therapy usually does not help because it may cause more confusion.
People with mild cognitive impairment do not always develop dementia. However, when dementia does occur, it usually gets worse and often decreases quality of life and lifespan.
Complications depend on the cause of the dementia, but may include the following:
- Abuse by an overstressed caregiver
- Increased infections anywhere in the body
- Loss of ability to function or care for self
- Loss of ability to interact
- Reduced lifespan
- Side effects of medications used to treat the disorder
Calling your health care provider
Call your health care provider if:
- Dementia develops or a sudden change in mental status occurs
- The condition of a person with dementia gets worse
- You are unable to care for a person with dementia at home
Most causes of dementia are not preventable.
You can reduce the risk of vascular dementia, which is caused by a series of small strokes, by quitting smoking and controlling high blood pressure and diabetes. Eating a low-fat diet and exercising regularly may also reduce the risk of vascular dementia.
Brewer JB, Gabrieli JDE, Preston AR, Vaidya CJ, Rosen AC. Memory. In: Goetz CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 5.
Farlow MR, Cummings JL. Effective pharmacologic management of Alzheimer's disease. Am J Med, 2007;120:388-397.
Burns A, Iliffe S. Alzheimer's disease. BMJ. 2009;338:b158.doi:10.1136/bmj.b158.
Reviewed By: Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.