Dementia is the loss of cognitive functioning—the ability to think, remember, problem solve or reason—to such an extent that it interferes with a person’s daily life and activities.
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 daily living.
Functions affected 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.
Signs and symptoms of dementia result when once-healthy neurons (nerve cells) in the brain stop working, lose connections with other brain cells, and die. While everyone loses some neurons as they age, people with dementia experience far greater loss.
Unlike dementia, age-related memory loss isn’t disabling. While dementia is more common with advanced age (as many as half of all people age 85 or older may have some form of dementia), it is not normal part of aging. Many people live into their 90s and beyond without any signs of dementia.
The causes of dementia can vary. Many people with dementia have both Alzheimer’s disease and one or more closely related disorders that share brain scanning or clinical (and sometimes both) features with Alzheimer’s disease.
When a person is affected by more than one dementia disorder, the dementia can be referred to as a mixed dementia. Some people may have mixed dementia caused by Alzheimer’s-related neurodegenerative processes, vascular disease-related processes, or another neurodegenerative condition.
Many other conditions such as Creutzfeldt-Jakob disease, Huntington’s Disease, and chronic traumatic encephalopathy can cause dementia or dementia-like symptoms.
Risk factors for dementia include advancing age, stroke, high blood pressure, poorly controlled diabetes, and a thickening of blood vessel walls (atherosclerosis).
Other dementias include frontotemporal disorders, vascular dementia, and Lewy body dementia.
No treatments currently exist to stop or slow dementia caused by neurodegenerative diseases or progressive dementias.
Drugs such as donepezil, rivastigmine, and galantamine can temporarily improve or stabilize memory and thinking skills in some people. Some studies suggest that drugs that improve memory in Alzheimer’s might benefit people with early vascular dementia.
Some diseases that occur at the same time as dementia, such as diabetes and depression, can be treated. Other drugs may help manage certain symptoms and behavioral problems associated with the disorders.
Some symptoms that may occur in dementia-like conditions can also be treated, although some symptoms may only respond to treatment for a period of time.
A team of specialists—doctors, nurses, and speech, physical, and other therapists—familiar with these disorders can help guide patient care.
Many disorders can cause dementia or dementia-like symptoms. Some, such as Alzheimer’s disease or Huntington’s disease, lead to a progressive loss of mental functions.
Many conditions that cause dementia-like symptoms can be halted or even reversed with the appropriate treatment.
Individuals with dementia and caregivers can face challenges including the person’s ability to handle tasks, changes in family relationships, loss of work, and long-term care.
Individuals may need assistance with daily activities. People with advanced dementia may need constant care and supervision.
Dementia disorders are not easy to live with, but with help, people can meet the challenges and prepare for the future. Getting an early accurate diagnosis and the right medical team are crucial first steps.
Several ongoing clinical studies are helping researchers better understand the dementias and find better ways to safely detect, treat, or prevent dementias. A number of drugs and compounds that might slow the progression of Alzheimer’s disease and other dementias are in various stages of testing.
NIH scientists continue to look for new genes that may be responsible for the development of Alzheimer’s disease and other forms of dementia.
Several research projects hope to identify dementia biomarkers (measurable biological signs that may indicate disease risk and progression or confirm diagnosis).
Scientists are also studying groups of people over time in hopes of finding ways to identify those at risk of developing dementia or cognitive impairment.