Dementia describes a group of symptoms affecting memory, thinking and social abilities severely enough to interfere with your daily life. It isn't a specific disease, but several different diseases may cause dementia.
Though dementia generally involves memory loss, memory loss has different causes. Having memory loss alone doesn't mean you have dementia.Alzheimer's disease is the most common cause of a progressive dementia in older adults, but there are a number of causes of dementia. Depending on the cause, some dementia symptoms may be reversible.
See a doctor if you or a loved one has memory problems or other dementia symptoms. Some treatable medical conditions can cause dementia symptoms, so it's important to determine the underlying cause.
- Dementia is caused by damage to or loss of nerve cells and their connections in the brain. Depending on the area of the brain that's affected by the damage, dementia can affect people differently and cause different symptoms.
- 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.
Types of dementias that progress and aren't reversible include:
- Alzheimer's disease. Alzheimer's disease 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.
- Vascular dementia. This second most common type of dementia is caused by damage to the vessels that supply blood to your brain. Blood vessel problems can cause strokes or damage the brain in other ways, such as by damaging the fibers in the white matter of the brain.
- 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.
- Frontotemporal dementia. This is a group of diseases characterized by the breakdown (degeneration) of nerve cells and their connections in the frontal and temporal lobes of the brain, 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
Some causes of dementia or dementia-like symptoms can be reversed with treatment. They include:
- Infections and immune disorders.
- Metabolic problems and endocrine abnormalities.
- Nutritional deficiencies.
- Medication side effects. Side effects of medications, a reaction to a medication or an interaction of several medications can cause dementia-like symptoms.
- Subdural hematomas. Bleeding between the surface of the brain and the covering over the brain, which is common in the elderly after a fall, can cause symptoms similar to those of dementia.
- Poisoning. Exposure to heavy metals, such as lead, and other poisons, such as pesticides, as well as recreational drug or heavy alcohol use can lead to symptoms of dementia. Symptoms might resolve with treatment.
- Brain tumors. Rarely, dementia can result from damage caused by a brain tumor.
- Anoxia. This condition, also called hypoxia, occurs when organ tissues aren't getting enough oxygen. Anoxia can occur due to severe sleep apneas, asthma, heart attack, carbon monoxide poisoning or other causes.
- Normal-pressure hydrocephalus. This condition, which is caused by enlarged ventricles in the brain, can cause walking problems, urinary difficulty and memory loss.
Many factors can eventually contribute to dementia. Some factors, such as age, can't be changed. Others can be addressed to reduce your risk.
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.
Risk factors you can change
You might be able to control the following risk factors for dementia.
- Diet and exercise.
- Heavy alcohol use.
- Cardiovascular risk factors.
- Sleep apnea.
- Vitamin and nutritional deficiencies.
Dementia can affect many body systems and, therefore, the ability to function. Dementia can lead to:
- Poor nutrition.
- Inability to perform self-care tasks.
- Personal safety challenges.
- Death. Late-stage dementia results in coma and death, often from infection.
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.
- Be physically and socially active.
- Quit smoking.
- Get enough vitamins.
- Manage cardiovascular risk factors.
- Treat health conditions. See your doctor for treatment if you experience hearing loss, depression or anxiety.
- Maintain a healthy diet.
Along with your test results, your doctor may use a combination of analysis techniques to help pinpoint where in the brain seizures start:
- Statistical parametric mapping (SPM). SPM is a method of comparing areas of the brain that have increased metabolism during seizures to normal brains, which can give doctors an idea of where seizures begin.
- Curry analysis. Curry analysis is a technique that takes EEG data and projects it onto an MRI of the brain to show doctors where seizures are occurring.
- Magnetoencephalography (MEG). MEG measures the magnetic fields produced by brain activity to identify potential areas of seizure onset.
Diagnosing dementia and its type can be challenging. People have dementia when they have cognitive impairment and lose their ability to perform daily functions, such as taking their medication, paying bills and driving safely.
No single test can diagnose dementia, so doctors are likely to run a number of tests that can help pinpoint the problem.
- Cognitive and neuropsychological tests Doctors will evaluate your thinking (cognitive) function. A number of tests measure thinking skills, such as memory, orientation, reasoning and judgment, language skills, and attention.
- Neurological evaluation
Doctors evaluate your memory, language, visual perception, attention, problem-solving, movement, senses, balance, reflexes and other areas.
- Brain scans
CT or MRI. These scans can check for evidence of stroke or bleeding or tumor or hydrocephalus.
PET scans. These can show patterns of brain activity and whether the amyloid protein, a hallmark of Alzheimer's disease, has been deposited in the brain.
- Laboratory tests
Simple blood tests can detect physical problems that can affect brain function, such as vitamin B-12 deficiency or an underactive thyroid gland. Sometimes the spinal fluid is examined for infection, inflammation or markers of some degenerative diseases.
- Psychiatric evaluation
A mental health professional can determine whether depression or another mental health condition is contributing to your symptoms. Treatment
Most types of dementia can't be cured, but there are ways to manage your symptoms.
The following are used to temporarily improve dementia symptoms.
- Cholinesterase inhibitors. These medications - including donepezil (Aricept), rivastigmine (Exelon) and galantamine (Razadyne) - work by boosting levels of a chemical messenger involved in memory and judgment.
- Memantine. Memantine (Namenda) works by regulating the activity of glutamate, another chemical messenger involved in brain functions, such as learning and memory. In some cases, memantine is prescribed with a cholinesterase inhibitor.
A common side effect of memantine is dizziness.
Other medications. Your doctor might prescribe medications to treat other symptoms or conditions, such as depression, sleep disturbances, hallucinations, parkinsonism or agitation.