Dementia

Definition

Dementia is a loss of brain function that occurs with certain diseases. It affects one or more brain functions such as memory, thinking, language, judgment, or behavior. Dementia may also be referred to as major neurocognitive disorder.

Alternative Names

Lewy body dementia; DLB; Vascular dementia; Mild cognitive impairment; MCI; Alzheimer disease - dementia

Causes

Dementia usually occurs in older age. Most types are rare in people under age 60. The risk of dementia increases as a person gets older.

Most types of dementia are nonreversible and degenerative. Nonreversible means the changes in the brain that are causing the dementia cannot be stopped or turned back. Alzheimer disease is the most common type of dementia.

Another common type of dementia is vascular dementia. It is caused by poor blood flow to the brain, such as with stroke.

Lewy body disease is another cause of dementia in older adults. People with this condition have abnormal protein structures in certain areas of the brain. Any condition that results in injury to the brain can cause dementia.

The following medical conditions can also lead to dementia:

Some causes of dementia, such as those due to abnormal chemical processes in the body, may be stopped or reversed if they are found soon enough, including:

Symptoms

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

Dementia usually first appears as forgetfulness.

Mild cognitive impairment (MCI) is a condition in which a person has more memory and thinking problems than other people their age. People with MCI have mild problems with thinking and memory that do not interfere with daily activities. They often know about their forgetfulness. Not everyone with MCI develops dementia.

Symptoms of MCI include:

Early symptoms of dementia can include:

As dementia becomes worse, symptoms are more obvious and interfere with the ability to take care of oneself. Symptoms may include:

People with severe dementia can no longer:

Other symptoms that may occur with dementia:

Exams and Tests

A skilled health care provider can often diagnose dementia using the following:

Other tests may be ordered to find out if other problems may be causing dementia or making it worse. These conditions include:

The following tests and procedures may be done:

Treatment

Treatment depends on the condition causing the dementia. Some people may need to stay in the hospital for a short time.

Sometimes, medicines given for any condition, including dementia, can make a person's confusion worse. Stopping or changing these medicines is part of the treatment.

Certain mental exercises can help with dementia.

Treating conditions that can lead to dementia symptoms often greatly improve mental function. Such conditions include:

Medicines may be used to:

Someone with dementia will need support in the home as the condition gets worse. Family members or other caregivers can assist by helping the person cope with memory loss and behavior and sleep problems. It is important to make sure the homes of people who have dementia are safe for them.

Outlook (Prognosis)

People with MCI do not always develop dementia. When dementia does occur, it usually gets worse over time. Dementia often decreases quality of life and lifespan. Families will likely need to plan for their loved one's future care. The prognosis depends on the underlying cause. Some dementias rapidly progress to death while others can take years to get worse.

When to Contact a Medical Professional

Contact your provider if:

Prevention

Most causes of dementia are not preventable.

The risk of vascular dementia may be reduced by preventing strokes through:

References

Budson AE, Solomon PR. Evaluating the patient with memory loss or dementia. In: Budson AE, Solomon PR, eds. Memory Loss, Alzheimer's Disease, and Dementia. 3rd ed. Philadelphia, PA: Elsevier; 2022:chap 2.

Knopman DS. Cognitive impairment and dementia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 371.

Peterson R, Graff-Radford J. Alzheimer disease and other dementias. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 95.

Petersen RC, Lopez O, Armstrong MJ, et al. Practice guideline update summary: mild cognitive impairment: report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology. 2018;90(3):126-135. PMID: 29282327 pubmed.ncbi.nlm.nih.gov/29282327/.


Review Date: 1/23/2022
Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Internal review and update on 02/23/24 by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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