Dementia

Definition

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

Alternative Names

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.

Symptoms

Dementia symptoms include difficulty with many areas of mental function, including:

• Language
• Memory
• Perception
• 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:

• Incontinence
• Swallowing problems

Content
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Reviewer Info: 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.; ADAM Health Illustrated Encyclopedia, 08/29/2009

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.