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.

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

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:

• Huntington disease
• Brain injury
• Frontotemporal degeneration (Pick disease)
• Multiple sclerosis
• Infections such as HIV/AIDS, syphilis, and Lyme disease
• Parkinson disease
• Progressive supranuclear palsy
• Excess alcohol use
• Brain trauma

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:

• Brain injury
• Brain tumors
• Long-term (chronic) alcohol abuse
• Changes in blood sugar, sodium, and calcium levels
• Low vitamin B12 level
• Normal pressure hydrocephalus
• Use of certain medicines, including cimetidine and some cholesterol medicines
• Some brain infections

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

• Emotional behavior or personality
• Language
• Memory
• Perception
• Thinking and judgment (cognitive skills)

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:

• Difficulty doing more than one task at a time
• Difficulty solving problems or making decisions
• Forgetting names of familiar people, recent events, or conversations
• Taking longer to do more difficult mental activities

Early symptoms of dementia can include:

• Difficulty with 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
• Getting lost on familiar routes
• Language problems, such as trouble with the names of familiar objects
• Losing interest in things previously enjoyed, flat mood
• Misplacing items
• Personality changes and loss of social skills, which can lead to inappropriate behaviors
• Mood changes leading to aggressive behavior
• Poor performance of job duties

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

• Change in sleep patterns, often waking up at night
• Difficulty with basic tasks, such as preparing meals, choosing proper clothing, or driving
• Forgetting details about current events
• Wandering and getting lost
• Forgetting events in one's own life history, or losing self-awareness
• Having hallucinations, arguments, striking out, and violent behavior
• Having delusions, depression, and agitation
• 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

People with severe dementia can no longer:

• Perform basic activities of daily living, such as eating, dressing, and bathing
• Recognize family members
• Understand language

Other symptoms that may occur with dementia:

• Problems controlling bowel movements or urine
• Swallowing problems

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:

• Anemia
• Decreased blood oxygen (hypoxia)
• Depression
• Heart failure
• Infections
• Nutritional disorders
• Thyroid disorders

Medicines may be used to:

• Slow the rate at which symptoms get worse, though improvement with these medicines may be small
• Control problems with behavior, such as loss of judgment or confusion

Newer treatments can reduce levels of amyloid in the brains of people with Alzheimer disease. While they offer hope, they haven’t been proven to slow the disease.

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.

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.

Contact your provider if:

• Dementia symptoms develop 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.

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

• Eating healthy foods
• Exercising
• Quitting smoking
• Controlling high blood pressure
• Managing diabetes

Published Date: March 31, 2024
Published By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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/.