Dementia and Cognitive Impairment
[This section is taken largely from NINDS, 2017.]
Dementia is the name for a group of symptoms caused by disorders affecting the brain. It is not a specific disease (MedlinePlus, 2017).
Dementia is the loss of cognitive functioning—the ability to think, remember, or reason—to such an extent that it interferes with a person’s daily life and activities. These functions 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. 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 (ADLs).
Age is the primary risk factor for developing dementia. For that reason, the number of people living with dementia could double in the next 40 years as the number of Americans age 65 and older increases from 48 million today to more than 88 million in 2050. Regardless of the form of dementia, the personal, economic, and societal demands can be devastating.
Dementia is not the same as age-related cognitive decline—when certain areas of thinking, memory, and information processing slow with age, but intelligence remains unchanged. Unlike dementia, age-related memory loss isn’t disabling. Occasional lapses of forgetfulness are normal in older adults. 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 an inevitable part of aging. Many people live into their nineties and beyond without any signs of dementia.
Dementia is not the same as delirium, which is usually a short-term complication of a medical condition and most often can be treated successfully. 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.
Mild cognitive impairment (MCI) is a stage between normal cognitive changes that may occur with age and more serious symptoms that indicate dementia. Symptoms of MCI can include problems with thinking, judgment, memory, and language, but the loss doesn’t significantly interfere with the ability to handle everyday activities. Symptoms of MCI include mild memory loss; difficulty with planning or organization; trouble finding words; frequently losing or misplacing things; and forgetting names, conversations, and events.
Someone who has MCI may be at greater risk of eventually developing Alzheimer’s or another type of dementia, particularly if the degree of memory impairment is significant, but MCI does not always progress to dementia. Symptoms may remain stable for several years, and even improve over time in some people.
Researchers are still trying to understand the underlying disease processes involved in dementia. Scientists have some theories about mechanisms that may lead to different forms of dementia, but more research is needed to better understand if and how these mechanisms are involved.
Differentiating Dementia from Other Conditions
[This section is taken largely from NINDS, 2017.]
The symptoms of a number of medical conditions mimic those of dementia and this must be considered when evaluating a person experiencing cognitive changes. Gerontology specialists speak of the “Three Ds”—dementia, delirium, and depression—because these are the most prevalent reasons for cognitive impairment in older adults. Delirium and depression can cause cognitive changes that may be mistaken for dementia, and healthcare providers and caregivers should learn to distinguish among the three conditions.
There are other conditions that can cause dementia-like symptoms; many of these conditions can be stopped and may be reversible with appropriate treatment:
- Normal pressure hydrocephalus is an abnormal buildup of cerebrospinal fluid in the brain. Elderly individuals with the condition usually have trouble with walking and with bladder control before the onset of dementia. Normal pressure hydrocephalus can be treated or even reversed by implanting a shunt system to divert fluid from the brain.
- Nutritional deficiencies of vitamin B1 (thiamine), caused by chronic alcoholism, and of vitamin B12, can be reversed with treatment. People who have abused substances such as alcohol and recreational drugs sometimes display signs of dementia even after the substance abuse has stopped.
- Side effects of medications or drug combinations may cause cognitive impairment that looks like a degenerative or vascular dementia but which could reverse upon stopping these medications.
- Vasculitis, an inflammation of brain blood vessels, can cause dementia after multiple strokes and may be treated with immunosuppressive medications.
- Subdural hematoma, or bleeding between the brain’s surface and its outer covering (the dura), is common after a fall. Subdural hematomas can cause dementia-like symptoms and changes in mental function. With treatment, some symptoms can be reversed.
- Some non-malignant brain tumors can cause symptoms resembling dementia and recovery occurs following their removal by neurosurgery.
- Some chronic infections around the brain, so-called chronic meningitis, can cause dementia and may be treatable by drugs that kill the infectious agent.
[This section is taken largely from NINDS, 2017.]
To diagnose dementia, doctors first assess whether an individual has an underlying treatable condition such as abnormal thyroid function, vitamin deficiency, or normal pressure hydrocephalus that may relate to cognitive difficulties. Early detection of symptoms is important, as some causes can be treated. In many cases, the specific type of dementia may not be confirmed until after the person has died and the brain is examined. An assessment generally includes:
- Medical history and physical exam. Assessing a person’s medical and family history, current symptoms and medication, and vital signs can help the doctor detect conditions that might cause or occur with dementia. Some conditions may be treatable.
- Neurologic evaluations. Assessing balance, sensory response, reflexes, and other functions helps the doctor identify signs of conditions that may affect the diagnosis or are treatable with drugs. Doctors also might use an electroencephalogram, a test that records patterns of electrical activity in the brain, to check for abnormal electrical brain activity.
- Brain scans. Computed tomography (CT) and magnetic resonance imaging (MRI) can detect structural abnormalities and rule out other causes of dementia. Positron-emission tomography (PET) can look for patterns of altered brain activity that are common in dementia. Recent advances in PET can detect amyloid plaques and tau tangles in AD.
- Cognitive and neuropsychological tests. These tests are used to assess memory, language skills, math skills, problem-solving, and other abilities related to mental functioning.
- Laboratory tests. Testing a person’s blood and other fluids, as well as checking levels of various chemicals, hormones, and vitamin levels, can identify or rule out conditions that may contribute to dementia.
- Pre-symptomatic tests. Genetic testing can help some people who have a strong family history of dementia identify risk for a dementia with a known gene defect.
- Psychiatric evaluation. This evaluation will help determine if depression or another mental health condition is causing or contributing to a person’s symptoms.
Types of Dementia
[This section is taken largely from NINDS, 2017.]
Various disorders and factors contribute to dementia, resulting in a progressive and irreversible loss of neurons and brain functions. Currently, there are no cures for these neurodegenerative disorders.
Alzheimer’s disease (AD) is the most common cause of dementia in older adults. As many as 5 million Americans age 65 and older may have the disease. In most neurodegenerative diseases, certain proteins abnormally clump together and are thought to damage healthy neurons, causing them to stop functioning and die. In Alzheimer’s, fragments of a protein called amyloid form abnormal clusters called plaques between brain cells, and a protein called tau forms tangles inside nerve cells.
It seems likely that damage to the brain starts a decade or more before memory and other cognitive problems appear. The damage often initially appears in the hippocampus, the part of the brain essential in forming memories. Ultimately, the abnormal plaques and tangles spread throughout the brain, and brain tissue significantly shrinks.
As Alzheimer’s disease progresses, people experience greater memory loss and other cognitive difficulties. Problems can include wandering and getting lost, trouble handling money and paying bills, repeating questions, taking longer to complete normal daily tasks, and personality and behavior changes.
People are often diagnosed in this stage. Memory loss and confusion worsen, and people begin to have problems recognizing family and friends. They may be unable to learn new things, carry out multi-step tasks such as getting dressed, or cope with new situations. In addition, people at this stage may experience hallucinations, delusions, and paranoia and may behave impulsively.
People with severe Alzheimer’s cannot communicate and are completely dependent on others for their care. Near the end, the person may be in bed most or all of the time as body functions shut down. Certain drugs can temporarily slow some symptoms of Alzheimer’s from getting worse, but currently there are no treatments that stop the progression of the disease.
Researchers have not found a single gene solely responsible for Alzheimer’s disease; rather, multiple genes are likely involved.
Today, 5.8 million Americans have Alzheimer’s disease (5.2 million are over age 65) and about two-thirds of them are women. By 2050 up to 14 million people will have AD. In 2019 Alzheimer’s and other dementias will cost the nation $290 billion, with Medicare and Medicaid paying 67% of that. Older African Americans are twice as likely as older whites to have Alzheimer’s or other dementias (Alzheimer’s Association, 2019).
Frontotemporal disorders (FTD) are forms of dementia caused by a family of neurodegenerative brain diseases collectively called frontotemporal lobar degeneration. They primarily affect the frontal and temporal lobes of the brain, rather than the widespread shrinking and wasting away (atrophy) of brain tissue seen in Alzheimer’s disease. In these disorders, changes to nerve cells in the brain’s frontal lobes affect the ability to reason and make decisions, prioritize and multitask, act appropriately, and control movement.
Changes to the temporal lobes affect memory and how people understand words, recognize objects, and recognize and respond to emotions. Some people decline rapidly over 2 to 3 years, while others show only minimal changes for many years. People can live with frontotemporal disorders for 2 to 10 years, sometimes longer, but it is difficult to predict the time course for an affected individual. The signs and symptoms may vary greatly among individuals as different parts of the brain are affected. No treatment that can cure or reverse frontotemporal disorders is currently available.
Lewy Body Dementia
Lewy body dementia (LBD) is one of the most common causes of dementia after Alzheimer’s disease and vascular disease. It typically begins after age 50, but can occur earlier. It involves abnormal protein deposits called Lewy bodies, which are balloon-like structures that form inside nerve cells. The abnormal buildup of the protein alpha-synuclein and other proteins causes neurons to work less effectively and die. Initial symptoms may vary, but over time people with these disorders develop similar cognitive, behavioral, physical, and sleep-related symptoms.
Lewy body dementia includes two related conditions—dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD). In dementia with Lewy bodies, the cognitive symptoms are seen within a year of movement symptoms called parkinsonism (including tremor, difficulty with walking and posture, and rigid muscles). In Parkinson’s disease dementia, the cognitive symptoms develop more than a year after movement problems begin.
Vascular Contributions to Cognitive Impairment and Dementia
Vascular contributions to cognitive impairment and dementia (VCID) cause significant changes to memory, thinking, and behavior. Cognition and brain function can be significantly affected by the size, location, and number of brain injuries.
Vascular dementia and vascular cognitive impairment arise as a result of risk factors that similarly increase the risk for cerebrovascular disease (stroke), including atrial fibrillation, hypertension, diabetes, and high cholesterol. Symptoms of VCID can begin suddenly and progress or subside during the lifetime. VCID can occur along with Alzheimer’s disease.
People with VCID almost always have abnormalities in the brain on magnetic resonance imaging (MRI) scans. These include evidence of prior strokes, often small and asymptomatic, as well as diffuse changes in the brain’s “white matter”—the connecting “wires” of the brain that are critical for relaying messages between brain regions. Microscopic brain examination shows thickening of blood vessel walls called arteriosclerosis and thinning or loss of components of the white matter.
Other Neurodegenerative Diseases and Conditions
Doctors have identified many other conditions that can cause dementia or dementia-like symptoms. The diseases have different symptoms that involve body and brain functions, and affect mental health and cognition.
Argyrophilic grain disease is a common, late-onset degenerative disease that affects brain regions involved in memory and emotion. It causes cognitive decline and changes in memory and behavior, with difficulty finding words. The disease’s signs and symptoms are indistinguishable from late-onset AD. Confirmation of the diagnosis can be made only at autopsy.
Creutzfeldt-Jakob disease is a rare brain disorder that is characterized by rapidly progressing dementia. Scientists found that infectious proteins called prions become misfolded and tend to clump together, causing the brain damage. Initial symptoms include impaired memory, judgment, and thinking, along with loss of muscle coordination and impaired vision. Some symptoms of CJD can be similar to symptoms of other progressive neurologic disorders, such as Alzheimer’s disease.
Chronic traumatic encephalopathy (CTE) is caused by repeated traumatic brain injury (TBI) in some people who suffered multiple concussions. People with CTE may develop dementia, poor coordination, slurred speech, and other symptoms similar to those seen in Parkinson’s disease 20 years or more after the injury. Late-stage CTE is also characterized by brain atrophy and widespread deposits of tau in nerve cells. In some people, even just 5 to 10 years beyond the traumatic brain injury, behavioral and mood changes may occur. Dementia may not yet be present and the brain may not have started to shrink, but small deposits of tau are seen in specific brain regions at autopsy.
Huntington’s disease is an inherited, progressive brain disease that affects a person’s judgment, memory, ability to plan and organize, and other cognitive functions. Symptoms typically begin around age 30 or 40 years and include abnormal and uncontrollable movements called chorea, as well as problems with walking and lack of coordination. Cognitive problems worsen as the disease progresses, and problems controlling movement lead to complete loss of ability for self-care.
HIV-associated dementia (HAD) can occur in people who have human immunodeficiency virus, the virus that causes AIDS. HAD damages the brain’s white matter and leads to a type of dementia associated with memory problems, social withdrawal, and trouble concentrating. People with HAD may develop movement problems as well. The incidence of HAD has dropped dramatically with the availability of effective antiviral therapies for managing the underlying HIV infections.
Secondary dementias occur in people with disorders that damage brain tissue. Such disorders may include multiple sclerosis, meningitis, and encephalitis, as well as Wilson’s disease (in which excessive amounts of copper build up to cause brain damage). People with malignant brain tumors may develop dementia or dementia-like symptoms because of damage to their brain circuits or a buildup of pressure inside the skull.
Care of Those with Dementia
Those with moderate or advanced dementia often need round-the-clock care and supervision and also may need assistance with ADLs such as eating, bathing, and dressing. Meeting these needs takes patience, understanding, and careful thought by the person’s caregivers.
Communicating with a person who has dementia is a learned skill. Important elements include:
- Setting a positive mood
- Getting the person’s attention
- Stating your message clearly
- Asking simple answerable questions
- Listening with ears, eyes, and heart
- Breaking activities into steps
- Using distraction and redirection to deal with upset and agitation
- Responding with affection and reassurance
- Remembering the past as a soothing technique
- Maintaining a sense of humor
Caregiving is a challenging task made even more so when caring for someone with dementia. Print, online, and in-person resources can help caregivers:
- Modify the environment to make it safer and help keep the person with dementia from wandering
- Understand frustrating behaviors and how to work with the person
- Deal with personal issues of cleanliness—toileting, bathing, and dressing
- Manage diet and nutrition
- Provide activities and exercise
- Deal with agitation, paranoia, and other difficult behaviors (FCA, 2016)
Eighty-three percent of the help provided to older adults in the United States is provided by family members, friends, and other unpaid caregivers. Nearly half of all caregivers are caring for someone with Alzheimer’s or another dementia, which in many cases exacts a larger emotional, financial, and physical toll on caregivers than caring someone without dementia (Alzheimer’s Association, 2019).
Often overlooked by family caregivers is the need to care for themselves (FCA, 2016).