Dementia is a general term for a group of brain disorders that cause memory problems associated with other disturbances of thinking.
Although dementia mainly affects older people, it is not an inevitable consequence of aging. Currently more than 55 million people live with dementia worldwide and nearly 10 million new cases are diagnosed each year. Alzheimer’s disease is the most common form of dementia and represents approximately 60-70% of cases. Dementia is the seventh leading cause of death among all disease and one of the major causes of disability and dependency among older people globally. Dementia has physical, psychological, social, and economic impacts for not only the people living with dementia but also for their families and society at large.
Symptoms of Dementia
The symptoms of dementia usually start off very mild and get worse slowly. Symptoms may include the following:
- Acting confused or disoriented
- Trouble with speech and writing (not being able to find the right words or understand speech)
- Difficulty concentrating and reasoning
- Problems with tasks such as paying bills or balancing a checkbook
- Getting lost in familiar places
- Planning usual activities and events
As dementia gets worse, people might:
- Have episodes of anger or aggression
- See things that are not there or believe things that are not true
- Be unable to eat, bathe, dress, or do other everyday tasks
- Lose control of bladder or bowel function
Types of Dementia
- 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 certain genes, which can be passed down from parent to child. While several genes are probably involved in Alzheimer’s disease, one important gene variant that is associated with an increased risk is apolipoprotein E4 (Apo-E4). Alzheimer’s disease patients have “plaques” and “tangles” in their brains. Plaques are clumps of a protein called beta-amyloid, and tangles are fibrous , twisted filaments made up of a protein called tau. It is thought that these clumps damage healthy neurons and the fibers connecting them, but they may just be a marker of damage from an unknown process. The cause of these changes is currently unknown.
- Vascular Dementia – This type of dementia is caused by damage to the vessels that supply blood to the 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, where connections between brain areas occurs. The most common signs of vascular dementia include difficulties with problem-solving, slowed thinking, slow movement, and loss of focus and organization. These tend to be more noticeable than memory loss.
- Lewy Body Dementia – Lewy bodies are abnormal balloon-like clumps of protein that have been found in the brain of people with Lewy body dementia, but also in Alzheimer’s disease and Parkinson’s disease. The hallmark symptoms of the actual disease named after these deposits are seeing things that are not there (visual hallucinations) and dementia. Other signs include uncoordinated or slow movement, tremors, and rigidity similar to those with Parkinson disease.
- 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, language, and movement. Features of these are more subtle than memory disturbances—which may be delayed—and so Frontotemporal dementia is often misdiagnosed as Alzheimer disease or even just being "ornery.”
- Mixed Dementia – Autopsy studies of the brain 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.
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 include severe decline in thinking, usually appearing around the age of 30 or 40, and a certain kind of movement disorder called chorea.
- Traumatic Brain Injury (TBI) – Most often caused by repetitive head trauma. Boxers, football players, and soldiers might develop TBI. Depending on the part of the brain that is injured, this condition can cause dementia signs and symptoms such as depression, explosiveness, memory loss, and impaired speech along with parkinsonism. Symptoms may not appear until years after the trauma.
- Creutzfeldt-Jakob Disease – This is a rare brain disorder usually occurring in people without known risk factors and can be due to deposits of an aberrant protein called prion but can rarely be inherited or from exposure to diseased brain or nervous system tissue (such as from a cornea transplant). Signs and symptoms of this fatal condition usually appear after the age of 60.
- Parkinson’s Disease – Many people with Parkinson’s Disease eventually develop dementia symptoms.
Dementia-Like Conditions That Can be Reversed
Some causes of dementia or dementia-like symptoms can be reversed with treatment. These include the following:
- Infectious and immune disorders – Dementia-like symptoms can result from fever or other side effects of your body's attempt to fight off an infection. Multiple sclerosis and other conditions caused by the body's immune system attacking nerve cells also can cause dementia.
- Metabolic problems and endocrine abnormalities – People with thyroid problems, low blood sugar (hypoglycemia), too little or too much sodium or calcium, or problems absorbing vitamin B-12 can develop dementia-like symptoms or other personality changes.
- Nutritional deficiencies – Not drinking enough liquids (dehydration); not getting enough thiamin (vitamin B-1), which is common in people with chronic alcoholism; and not getting enough vitamin B-6 and B-12 in your diet can cause dementia-like symptoms. Copper and vitamin E deficiencies can also rarely cause dementia symptoms.
- Medication side effects – Side effects, interactions, or reactions to certain medication 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 like those of dementia.
- Brain tumors – Occasionally, dementia can result from damage caused by a brain tumor.
- Normal-pressure hydrocephalus – This condition, which is caused by intermittent increases in pressure in the fluid-filled cavities, ventricles, in the brain, can result in walking problems, urinary difficulty, and memory loss.
Risk Factors for Dementia
Many factors can eventually contribute to dementia. Some factors, such as age, cannot be modified. Others can be addressed to reduce your risk.
- Age – The risk rises as you age, especially after age 65. However, dementia is not a normal part of aging. Dementia can occur in younger people.
- Family history – Having a family history of dementia puts you at a greater risk for developing dementia. Nevertheless, many people with a family history never develop symptoms and many people without a family history do.
- Down Syndrome – By middle age, most people with Down Syndrome develop Alzheimer’s Disease.
Modifiable Risk Factors
Some risk factors can be mitigated and include the following:
- Diet and exercise –Lack of exercise increases the risk of dementia. While no specific diet is known to reduce dementia risk, research does find s a greater incidence of dementia in people who eat an unhealthy diet compared with those who follow a Mediterranean-style diet rich in produce, whole grains, nuts, and seeds.
- Excessive alcohol use – Drinking large amounts of alcohol has long been known to cause brain changes, particularly early-onset dementia.
- Cardiovascular risk factors – These include hypertension, hyperlipidemia, and obesity.
- Air pollution
- Head trauma – People who have had a severe head trauma have a greater risk of Alzheimer’s disease. Some studies indicate that the risk may be greatest within the first six months to two years after head trauma.
- Sleep disturbances – People with sleep apnea and other sleep disturbances might have a higher risk of developing dementia.
- Vitamin and nutritional deficiencies – Low levels of vitamin D, vitamin B-6, vitamin B-12, and folate can increase risk of dementia.
- Medications that can worsen memory – avoid over-the-counter sleep aids that contain diphenhydramine and medications used to treat urinary urgency.
There is no sure way to prevent dementia; however, there are steps that can be taken to reduce the risk.
- Keep mind active – Mentally stimulating activities such as reading, solving puzzles, 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 interactions might delay onset of dementia and reduce its symptoms. Aim for 150 minutes of exercise each week.
- Stop smoking.
- Get enough vitamins.
- Manage cardiovascular risk factors – Treat high blood pressure, high cholesterol, and diabetes. Lose weight if overweight.
- Treat depression and anxiety.
- Maintain a healthy diet – Recommend following a Mediterranean diet.
- Get good quality 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 reduce risk.
Diagnosing dementia and its cause can be challenging. There is no single test that can diagnose dementia so doctors will likely run several tests that can help pinpoint the underlying problem. Such tests may include laboratory studies, imaging with CT scan of brain or MRI of brain, lumbar puncture, electroencephalogram, physical examination, and cognitive, neurological, psychological evaluations. However, the most important information is the history of the problem given through a family member.
Unfortunately, most types of dementia cannot be cured, but there are often ways to manage the symptoms. Medications, therapies, and lifestyle modifications can be utilized and include the following:
- Medications – Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) which work by boosting levels of the chemical messenger involved in memory and judgement (acetylcholine); and memantine, used to regulate the activity of glutamate, a chemical messenger involved in learning and memory.
- Therapies – Several dementia symptoms and behavioral problems might be treated initially be used non-drug approaches.
- Occupational therapy
- Modifying the environment
- Simplifying tasks
- Lifestyle remedies – Dementia symptoms and behavioral problems will progress over time. Caregivers and care partners might try these suggestions:
- Enhance communication
- Encourage exercise
- Engage in activity
- Establish a nighttime ritual
- Keep a calendar
- Plan for the future
The Mayo Clinic, The National Institutes of Health, UptoDate.com