Dementia affects millions of people and is more common as people grow older (about one-third of all people age 85 or older may have some form of dementia) but it is not a normal part of aging. Many people live into their 90s and beyond without any signs of dementia.
There are several different forms of dementia, including Alzheimer’s disease, which is the most common.
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.
The signs and symptoms can vary depending on the type and may include:
Experiencing memory loss, poor judgment, and confusion
Difficulty speaking, understanding and expressing thoughts, or reading and writing
Wandering and getting lost in a familiar neighborhood
Trouble handling money responsibly and paying bills
Repeating questions
Using unusual words to refer to familiar objects
Taking longer to complete normal daily tasks
Losing interest in normal daily activities or events
Hallucinating or experiencing delusions or paranoia
Acting impulsively
Not caring about other people’s feelings
Losing balance and problems with movement
People with intellectual and developmental disabilities can also develop dementia as they age, and in these cases, recognizing their symptoms can be particularly difficult. It’s important to consider a person’s current abilities and to monitor for changes over time that could signal dementia.
What causes dementia?
Dementia is the result of changes in certain brain regions that cause neurons (nerve cells) and their connections to stop working properly. Researchers have connected changes in the brain to certain forms of dementia and are investigating why these changes happen in some people but not others. For a small number of people, rare genetic variants that cause dementia have been identified.
Although we don’t yet know for certain what, if anything, can prevent dementia, in general, leading a healthy lifestyle may help reduce risk factors.
Dementias are often grouped by what they have in common, such as the protein or proteins deposited in the brain or the part of the brain that's affected. Some diseases look like dementias, such as those caused by a reaction to medications or vitamin deficiencies, and they might improve with treatment.
Progressive dementias
Types of dementias that progress and aren't reversible include:
Alzheimer's disease. This is the most common cause of dementia.
Although not all causes of Alzheimer's disease are known, experts do know that a small percentage are related to mutations of three genes, which can be passed down from parent to child. While several genes are probably involved in Alzheimer's disease, one important gene that increases risk is apolipoprotein E4 (APOE).
Alzheimer's disease patients have plaques and tangles in their brains. Plaques are clumps of a protein called beta-amyloid, and tangles are fibrous tangles made up of tau protein. It's thought that these clumps damage healthy neurons and the fibers connecting them.
Vascular dementia. This type of dementia is caused by damage to the vessels that supply blood to your brain. Blood vessel problems can cause strokes or affect the brain in other ways, such as by damaging the fibers in the white matter of the brain.
The most common signs of vascular dementia include difficulties with problem-solving, slowed thinking, and loss of focus and organization. These tend to be more noticeable than memory loss.
Lewy body dementia. Lewy bodies are abnormal balloonlike clumps of protein that have been found in the brains of people with Lewy body dementia, Alzheimer's disease and Parkinson's disease. This is one of the more common types of progressive dementia.
Common signs and symptoms include acting out one's dreams in sleep, seeing things that aren't there (visual hallucinations), and problems with focus and attention. Other signs include uncoordinated or slow movement, tremors, and rigidity (parkinsonism).
Frontotemporal dementia. This is a group of diseases characterized by the breakdown of nerve cells and their connections in the frontal and temporal lobes of the brain. These are the areas generally associated with personality, behavior and language. Common symptoms affect behavior, personality, thinking, judgment, and language and movement.
Mixed dementia. Autopsy studies of the brains of people 80 and older who had dementia indicate that many had a combination of several causes, such as Alzheimer's disease, vascular dementia and Lewy body dementia. Studies are ongoing to determine how having mixed dementia affects symptoms and treatments.
Other disorders linked to dementia
Huntington's disease. Caused by a genetic mutation, this disease causes certain nerve cells in your brain and spinal cord to waste away. Signs and symptoms, including a severe decline in thinking (cognitive) skills, usually appear around age 30 or 40.
Traumatic brain injury (TBI). This condition is most often caused by repetitive head trauma. Boxers, football players or soldiers might develop TBI.
Depending on the part of the brain that's injured, this condition can cause dementia signs and symptoms such as depression, explosiveness, memory loss and impaired speech. TBI may also cause parkinsonism. Symptoms might not appear until years after the trauma.
Creutzfeldt-Jakob disease. This rare brain disorder usually occurs in people without known risk factors. This condition might be due to deposits of infectious proteins called prions. Signs and symptoms of this fatal condition usually appear after age 60.
Creutzfeldt-Jakob disease usually has no known cause but can be inherited. It may also be caused by exposure to diseased brain or nervous system tissue, such as from a cornea transplant.
Parkinson's disease. Many people with Parkinson's disease eventually develop dementia symptoms (Parkinson's disease dementia).
How is dementia diagnosed?
Doctor studying brain scans to diagnose dementia, doctors first assess whether a person has an underlying, potentially treatable, condition that may relate to cognitive difficulties. A physical exam to measure blood pressure and other vital signs, as well as laboratory tests of blood and other fluids to check levels of various chemicals, hormones, and vitamins, can help uncover or rule out possible causes of symptoms.
A review of a person’s medical and family history can provide important clues about risk for dementia. Typical questions might include asking about whether dementia runs in the family, how and when symptoms began, changes in behavior and personality, and if the person is taking certain medications that might cause or worsen symptoms.
The following procedures also may be used to diagnose dementia:
Cognitive and neurological tests. Used to evaluate thinking and physical functioning, these tests include assessments of memory, problem solving, language skills, and math skills, as well as balance, sensory response, and reflexes.
Brain scans. These tests can identify strokes, tumors, and other problems that can cause dementia. Scans also identify changes in the brain's structure and function. The most common scans are:
Computed tomography (CT), which uses X-rays to produce images of the brain and other organs
Magnetic resonance imaging (MRI), which uses magnetic fields and radio waves to produce detailed images of body structures, including tissues, organs, bones, and nerves
Positron emission tomography (PET), which uses radiation to provide pictures of brain activity — such as energy use — or specific molecules in different brain regions.
Psychiatric evaluation. If someone is experiencing behavioral or mood changes, a psychiatric evaluation may be recommended to help determine if depression or another mental health condition is causing or contributing to a person's symptoms.
Genetic tests. Some forms of dementia are caused by a person’s genes. In these rare cases, a genetic test ordered by a doctor can help people know if they have the altered genes. It is important to talk with a genetic counselor before and after getting tested, along with family members and the doctor. There are also genetic tests that look for genetic variations that affect someone’s risk of developing dementia, but these tests cannot be used to diagnose dementia.
Cerebrospinal fluid (CSF) tests. CSF is a clear fluid that surrounds the brain and the spinal cord, providing protection, insulation, and nutrients. Doctors collect CSF by performing a lumbar puncture, also called a spinal tap. Measuring the levels of proteins or other substances in CSF may be used to help diagnose Alzheimer's or other types of dementia.
Blood tests. It is now possible for many doctors, dependent on state-specific availability reflecting U.S. Food and Drug Administration guidelines, to order a blood test to measure levels of beta-amyloid, a protein that accumulates abnormally in people with Alzheimer’s. Several other blood tests are in development. At present, blood test results alone should not be used to diagnose dementia, but may be taken into consideration along with other tests. However, the availability of these diagnostic tests is still limited.
Some of the tests and procedures used to diagnose dementia may not be covered by health insurance. Check with your insurance provider and talk with your health care team to determine what options may work best for you.
Early detection of symptoms is important as some causes can be successfully treated. However, in many cases, the cause of dementia is unknown and cannot be effectively treated. Still, obtaining an early diagnosis can help with managing the condition and planning ahead. In the early stages of dementia, it may be possible for people to continue with their everyday activities. As the disease progresses, people will need to adopt new strategies to help adjust.
Risk factors
Risk factors that can't be changed:
Age. The risk rises as you age, especially after age 65. However, dementia isn't a normal part of aging, and dementia can occur in younger people.
Family history. Having a family history of dementia puts you at greater risk of developing the condition. However, many people with a family history never develop symptoms, and many people without a family history do. There are tests to determine whether you have certain genetic mutations.
Down syndrome. By middle age, many people with Down syndrome develop early-onset Alzheimer's disease.
Prevention
There's no sure way to prevent dementia, but there are steps you can take that might help. More research is needed, but it might be beneficial to do the following:
Keep your mind active. Mentally stimulating activities, such as reading, solving puzzles and playing word games, and memory training might delay the onset of dementia and decrease its effects.
Be physically and socially active. Physical activity and social interaction might delay the onset of dementia and reduce its symptoms. Aim for 150 minutes of exercise a week.
Quit smoking. Some studies have shown that smoking in middle age and beyond might increase your risk of dementia and blood vessel conditions. Quitting smoking might reduce your risk and will improve your health.
Get enough vitamins. Some research suggests that people with low levels of vitamin D in their blood are more likely to develop Alzheimer's disease and other forms of dementia.
Manage cardiovascular risk factors. Treat high blood pressure, high cholesterol and diabetes. Lose weight if you're overweight. High blood pressure might lead to a higher risk of some types of dementia. More research is needed to determine whether treating high blood pressure may reduce the risk of dementia.
Treat health conditions. See your doctor for treatment for depression or anxiety.
Maintain a healthy diet. A diet such as the Mediterranean diet — rich in fruits, vegetables, whole grains and omega-3 fatty acids, which are commonly found in certain fish and nuts — might promote health and lower your risk of developing dementia. This type of diet also improves cardiovascular health, which may help lower dementia risk.
Get good-quality sleep. Practice good sleep hygiene, and talk to your doctor if you snore loudly or have periods where you stop breathing or gasp during sleep.
Treat hearing problems. People with hearing loss have a greater chance of developing cognitive decline. Early treatment of hearing loss, such as use of hearing aids, might help decrease the risk.
Sources:
https://www.nhs.uk/conditions/dementia/living-well-with-dementia/
https://www.mayoclinic.org/diseases-conditions/dementia/symptoms-causes/syc-20352013
https://www.nia.nih.gov/health/what-is-dementia
Prepared by Viktorija Stučytė based on online sources
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