Dementia is a general term for loss of memorylanguageproblem-solving and other thinking abilities that are severe enough to interfere with daily life. Alzheimer's is the most common cause of dementia.

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About dementia

Dementia is not a single disease. It's an overall term to describe a collection of symptoms that one may experience if they are living with a variety of diseasesincluding Alzheimer's disease. Diseases grouped under the general term "dementia" are caused by abnormal brain changes. Dementia symptoms trigger a decline in thinking skillsalso known as cognitive abilitiessevere enough to impair daily life and independent function. They also affect behaviorfeelings and relationships.

Alzheimer's disease accounts for 60%-80% of cases. Vascular dementiawhich occurs because of microscopic bleeding and blood vessel blockage in the brainis the second most common cause of dementia. Those who experience the brain changes of multiple types of dementia simultaneously have mixed dementia. There are many other conditions that can cause symptoms of cognitive impairment but that aren't dementiaincluding some that are reversiblesuch as thyroid problems and vitamin deficiencies.

Dementia is often incorrectly referred to as "senility" or "senile dementia," which reflects the formerly widespread but incorrect belief that serious mental decline is a normal part of aging.

Learn more: Common Types of DementiaWhat is Alzheimer's?

Symptoms and signs of dementia

Signs of dementia can vary greatly. Examples include problems with:

• Short-term memory.
• Keeping track of a purse or wallet.
• Paying bills.
• Planning and preparing meals.
• Remembering appointments.
• Traveling out of the neighborhood.

Dementia symptoms are progressivewhich means that the signs of cognitive impairment start out slowly and gradually get worse over timeleading to dementia. If you or someone you know is experiencing memory difficulties or other changes in thinking skillsdon't ignore them. See a doctor soon to determine the cause. Professional evaluation may detect a treatable condition. And even if symptoms suggest dementiaearly diagnosis allows a person to get the maximum benefit from available treatments and provides an opportunity to volunteer for clinical trials or studies. It also provides time to plan for the future.

Learn more: 10 Warning SignsStages of Alzheimer's 

Causes

Dementia is caused by a variety of diseases that cause damage to brain cells. This damage interferes with the ability of brain cells to communicate with each other. When brain cells cannot communicate normallythinkingbehavior and feelings can be affected.

The brain has many distinct regionseach of which is responsible for different functions (for examplememoryjudgment and movement). When cells in a particular region are damagedthat region cannot carry out its functions normally.

Different types of dementia are associated with particular types of brain cell damage in particular regions of the brain. For examplein Alzheimer's diseasehigh levels of certain proteins inside and outside brain cells make it hard for brain cells to stay healthy and to communicate with each other. The brain region called the hippocampus is the center of learning and memory in the brainand the brain cells in this region are often the first to be damaged. That's why memory loss is often one of the earliest symptoms of Alzheimer's.

While most changes in the brain that cause dementia are permanent and worsen over timethinking and memory problems caused by the following conditions may improve when the condition is treated or addressed:

• Depression.
• Medication side effects.
• Excess use of alcohol.
• Thyroid problems.
• Vitamin deficiencies.

Diagnosis of dementia

There is no one test to determine if someone has dementia. Doctors diagnose Alzheimer's and other types of dementia based on a careful medical historya physical examinationlaboratory testsand the characteristic changes in thinkingday-to-day function and behavior associated with each type. Doctors can determine that a person has dementia with a high level of certainty. But it's harder to determine the exact type of dementia because the symptoms and brain changes of different dementias can overlap. In some casesa doctor may diagnose "dementia" and not specify a type. If this occursit may be necessary to see a specialist such as a neurologistpsychiatristpsychologist or geriatrician.

Learn more: Memory Tests

Dementia treatment and care

Treatment of dementia depends on its cause. In the case of most progressive dementiasincluding Alzheimer's diseasethere is no curebut two treatments — donanemab (Kisunla®) and lecanemab (Leqembi®) — demonstrate that removing beta-amyloidone of the hallmarks of Alzheimer’s diseasefrom the brain reduces cognitive and functional decline in people living with early Alzheimer’s. Others can temporarily slow the worsening of dementia symptoms and improve quality of life for those living with Alzheimer's and their caregivers. The same medications used to treat Alzheimer's are among the drugs sometimes prescribed to help with symptoms of other types of dementias. Non-drug therapies can also alleviate some symptoms of dementia.

Ultimatelythe path to effective new treatments for dementia is through increased research funding and increased participation in clinical studies. Right nowvolunteers are urgently needed to participate in clinical studies and trials about Alzheimer's and other dementias.

Learn more: Medications for Memory LossAlternative Treatments for Alzheimer's 

Dementia risk and prevention

Some risk factors for dementiasuch as age and genetics, cannot be changed. But researchers continue to explore the impact of other risk factors on brain health and prevention of dementia.

Learn more: Brain Health