Dementia is the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that it interferes with a person’s daily life and activities. These functions include memory, language skills, visual perception, problem solving, self-management, and the ability to focus and pay attention. Some people with dementia cannot control their emotions, and their personalities may change. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others for basic activities of living.
While dementia is more common as people grow older (up to half of all people age 85 or older may have some form of dementia), it is not a normal part of aging. Many people live into their 90s and beyond without any signs of dementia. One type of dementia, frontotemporal disorders, is more common in middle-aged than older adults.
The causes of dementia can vary, depending on the types of brain changes that may be taking place. Alzheimer’s disease is the most common cause of dementia in older adults. Other dementias include Lewy body dementia, frontotemporal disorders, and vascular dementia. It is common for people to have mixed dementia—a combination of two or more types of dementia. For example, some people have both Alzheimer’s disease and vascular dementia.
What are the Different Types of Dementia?
Hispanic man with dementia sitting in a parkVarious disorders and factors contribute to the development of dementia. Neurodegenerative disorders result in a progressive and irreversible loss of neurons and brain functioning. Currently, there are no cures for these types of disorders. They include:
Alzheimer’s disease
Frontotemporal disorders
Lewy body dementia
Other types of progressive brain disease include:
Vascular contributions to cognitive impairment and dementia
Mixed dementia, a combination of two or more types of dementia
Other conditions that cause dementia-like symptoms can be halted or even reversed with treatment. For example, normal pressure hydrocephalus, an abnormal buildup of cerebrospinal fluid in the brain, often resolves with treatment.
In addition, certain medical conditions can cause serious memory problems that resemble dementia. These problems should go away once the conditions are treated. These conditions include:
Side effects of certain medicines
Emotional problems, such as stress, anxiety, or depression
Certain vitamin deficiencies
Drinking too much alcohol
Blood clots, tumors, or infections in the brain
Delirium
Head injury, such as a concussion from a fall or accident
Thyroid, kidney, or liver problems
Doctors have identified many other conditions that can cause dementia or dementia-like symptoms. These conditions include:
Argyrophilic grain disease, a common, late-onset degenerative disease
Creutzfeldt-Jakob disease, a rare brain disorder
Huntington’s disease, an inherited, progressive brain disease
Chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury
HIV-associated dementia (HAD)
The overlap in symptoms of various dementias can make it hard to get an accurate diagnosis. But a proper diagnosis is important to get the right treatment. Seek help from a neurologist—a doctor who specializes in disorders of the brain and nervous system—or other medical specialist who knows about dementia.
To diagnose dementia, doctors first assess whether a person has an underlying treatable condition such as abnormal thyroid function, normal pressure hydrocephalus, or a vitamin deficiency that may relate to cognitive difficulties. Early detection of symptoms is important, as some causes can be treated. In many cases, the specific type of dementia a person has may not be confirmed until after the person has died and the brain is examined.
