Dementia is a collective term used to describe various symptoms of cognitive decline, such as forgetfulness. It is a symptom of several underlying diseases and brain disorders. Dementia is not a single disease in itself, but a general term to describe symptoms of impairment in memory, communication, and thinking.
A diagnosis of dementia can be frightening for those affected by the syndrome, their family members, and caretakers. Unfortunately, there is a stigma associated with this term. Learning more about this medical condition can help.
- The Basics of Dementia and Cognitive Impairment
- Dementias Associated with Aging and Neurodegeneration
- Neuropathology of Neurodegenerative Disorders
- Reversible Dementia-like Disorders and Conditions
- Other Neurodegenerative Diseases and Conditions that Include Dementia or Dementia-like Symptoms
- Risk Factors for Dementia and Vascular Cognitive Impairment
- Treatment and Management
The Basics of Dementia and Cognitive Impairment
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.
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 elderly 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 90s and beyond without any signs of dementia.
Dementia is also 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.
It is common to have more than one cause of dementia. Many people with dementia have both Alzheimer’s disease and one or more closely related disorders that share brain scanning or clinical features (and sometimes both) with Alzheimer’s disease. When a person is affected by more than one dementia disorder, dementia can be referred to as a mixed dementia.
Autopsy studies of the brains of people who had dementia suggest that a majority of those age 80 and older probably had mixed dementia caused by Alzheimer’s-related neurodegenerative processes, vascular disease-related processes, or another neurodegenerative condition. In fact, some studies indicate that mixed vascular-degenerative dementia is the most common cause of dementia in the elderly.
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.
Dementias Associated with Aging and Neurodegeneration
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.
Some specific causes of dementia disorders are explained below.
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 have 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. For more information on Alzheimer’s disease, visit the Alzheimer’s and related Dementias Education and Referral (ADEAR) Center at www.alzheimers.gov.
Researchers have not found a single gene solely responsible for Alzheimer’s disease; rather, multiple genes are likely involved. One genetic risk factor— having one form of the apolipoprotein E (APOE) gene on chromosome 19—does increase a person’s risk for developing Alzheimer’s. People who inherit one copy of this APOE ε4 allele have an increased chance of developing the disease; those who inherit two copies of the allele are at even greater risk. (An allele is a variant form of a pair of genes that are located on a particular chromosome and control the same trait.) The APOE ε4 allele may also be associated with an earlier onset of memory loss and other symptoms. Researchers have found that this allele is associated with an increased number of amyloid plaques in the brain tissue of affected people.
Frontotemporal disorders 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.
Clinically, FTD is classified into two main types of syndromes:
- Behavioral variant frontotemporal dementia (bvFTD) involves changes in behavior, judgment, and personality. People with this disorder may have problems with cognition, but their memory may stay relatively intact. They may do impulsive things that are out of character or may engage in repetitive, unusual behaviors. People with bvFTD also may say or do inappropriate things or become uncaring. Over time, language and/or movement problems may occur.
- Primary progressive aphasia (PPA) involves changes in the ability to speak, understand, and express thoughts and/or words and to write and read. Many people with PPA, though not all, develop symptoms of dementia. Problems with memory, reasoning, and judgment are not apparent at first but can develop and progress over time. Sometimes a person with PPA cannot recognize the faces of familiar people and common objects (called semantic PPA). Other individuals have increasing trouble producing speech and may eventually be unable to speak at all (called agrammatic PPA). PPA is a language disorder that is not the same as the problems with speech and ability to read and write (called aphasia) that can result from a stroke.
Other types of frontotemporal disorders include:
- Corticobasal degeneration (CBD) involves progressive nerve-cell loss and atrophy of specific areas of the brain, which can affect memory, behavior, thinking, language, and movement. The disease is named after parts of the brain that are affected—the cerebral cortex (the outer part of the brain) and the basal ganglia (structures deep in the brain involved with movement). Not everyone who has CBD has problems with memory, cognition, language, or behavior. The disease tends to progress gradually, with early symptoms beginning around age 60. Some of the movement symptoms of CBD are similar to those seen in Parkinson’s disease.
- Frontotemporal dementia with motor neuron disease (FTD/MND, also called FTD-ALS) is a combination of behavioral variant frontotemporal dementia and the progressive neuromuscular weakness typically seen in amyotrophic lateral sclerosis (ALS). ALS is a neurodegenerative disease that attacks nerve cells responsible for controlling voluntary muscles (muscle action that can be controlled, such as that in the arms, legs, and face). Symptoms of either disease may appear first, with other symptoms developing over time.
- Pick’s disease is characterized by Pick bodies—masses comprised of the protein tau that accumulate inside nerve cells, causing them to appear enlarged or balloon-like. It is usually seen with bvFTD but sometimes with PPA. Some symptoms are similar to those of Alzheimer’s disease, including loss of speech, changes in behavior, and trouble with thinking. However, while inappropriate behavior characterizes the early stages of Pick’s disease, memory loss is often the first symptom of Alzheimer’s. Antidepressants and antipsychotics can control some of the behavioral symptoms of Pick’s disease, but no treatment is available to stop the disease from progressing.
- Progressive supranuclear palsy (PSP) is a brain disease that can cause problems with thinking, memory, behavior, problem solving, and judgment. It also affects the control of eye movements, mood, speech, swallowing, vision, concentration, and language. Because certain parts of the brain that control movement are damaged, this disease shares some of the problems with movement seen in people with corticobasal degeneration and Parkinson’s disease.
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 and Parkinson’s disease dementia. 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.
- Dementia with Lewy bodies (DLB) is one of the more common forms of progressive dementia. Neurons in the outer layer of the brain (cortex) and in the substantia nigra (a region involved with the production of dopamine) degenerate. Many neurons that remain contain Lewy bodies.
Symptoms such as difficulty sleeping, loss of smell, and visual hallucinations often precede movement and other problems by as many as 10 years. Later in the course of DLB, some signs and symptoms are similar to Alzheimer’s
disease and may include memory loss, poor judgment, and confusion. Other signs and symptoms of DLB are similar to those of Parkinson’s disease, including difficulty with movement and posture, a shuffling walk, and
changes in alertness and attention. There is no cure for DLB, but there are drugs that control some symptoms.
- Parkinson’s disease dementia (PDD) can occur in people with Parkinson’s disease, but not all people with Parkinson’s disease will develop dementia. PDD may affect memory, social judgment, language, or reasoning. Autopsy studies show that people with PDD often have Lewy bodies in the cortex and other brain areas, and many have amyloid plaques and tau tangles like those found in people with Alzheimer’s disease, though it is not understood what these similarities mean. The time from the onset of movement symptoms to the onset of dementia symptoms varies greatly from person to person. Risk factors for developing PDD include the onset of Parkinson’s-related movement symptoms followed by mild cognitive impairment and REM sleep behavior disorder, which involves having frequent nightmares and hallucinations.
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 one’s lifetime. VCID can occur along with Alzheimer’s disease. Persons with VCID almost always have abnormalities in the brain on magnetic resonance imaging 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.
Forms of VCID include:
- Vascular dementia refers to progressive loss of memory and other cognitive functions caused by vascular injury or disease within the brain. Symptoms of vascular dementia may sometimes be difficult to distinguish from Alzheimer’s disease. Problems with organization, attention, slowed thinking, and problem solving are all more prominent in VCID, while memory loss is more prominent in Alzheimer’s.
- Vascular cognitive impairment involves changes with language, attention, and the ability to think, reason, and remember that are noticeable but are not significant enough to greatly impact daily life. These changes, caused
by vascular injury or disease within the brain, progress slowly over time.
- Post-stroke dementia can develop months after a major stroke. Not everyone who has had a major stroke will develop vascular dementia, but the risk for dementia is significantly higher in someone who has had a stroke.
- Multi-infarct dementia is the result of many small strokes (infarcts) and mini-strokes. Language or other functions may be impaired, depending on the region of the brain that is affected. The risk for dementia is significantly higher in someone who has had a stroke. Dementia is more likely when strokes affect both sides of the brain. Even strokes that don’t show any noticeable symptoms can increase the risk of dementia.
- Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an extremely rare inherited disorder caused by a thickening of the walls of small- and medium-sized blood vessels,
which reduces the flow of blood to the brain. CADASIL is associated with multi-infarct dementia, stroke, and other disorders. The first symptoms can appear in people between ages 20 and 40. CADASIL may have symptoms that can be confused with multiple sclerosis. Many people with CADASIL are undiagnosed.
- Subcortical vascular dementia, previously called Binswanger’s disease, involves extensive microscopic damage to the small blood vessels and nerve fibers that make up white matter. Some consider it an aggressive form of multi-infarct dementia. Cognitive changes include problems with short-term memory, organization, attention, decision making, and behavior. Symptoms tend to begin after age 60, and they progress in a stepwise manner. People with subcortical vascular disease often have high blood pressure, a history of stroke, or evidence of disease of the large blood vessels in the neck or heart valves.
- Cerebral amyloid angiopathy is a buildup of amyloid plaques in the walls of blood vessels in the brain. It is generally diagnosed when multiple tiny bleeds in the brain are discovered using magnetic resonance imaging.
Neuropathology of Neurodegenerative Disorders
The different forms of age-related dementia, as well as many age-related neurodegenerative diseases, are thought to be caused by changes in various proteins. These diseases are called proteinopathies because they involve the abnormal buildup of specific proteins in the brain. Mutations in genes that provide instructions for making these proteins have been found to cause dementia in families. However, in the vast majority of affected individuals, dementia is not inherited, and the cause is unknown. Alzheimer’s disease, frontotemporal disorders, and Lewy body dementia are proteinopathies.
In some dementias, changes in the protein tau cause it to form clumps inside nerve cells in the brain, which is believed to make the cells stop functioning properly and die. Disorders that are associated with the abnormal buildup of tau are called tauopathies.
In Alzheimer’s disease, the tau protein aggregates (accumulates into abnormal clumps) and becomes twisted and tangled, forming fibers— called neurofibrillary or tau tangles—inside neurons. Abnormal clumps (plaques) of another protein, called beta-amyloid, are prominent in spaces between brain cells. Both plaques and tangles are thought to contribute to reduced function and nerve-cell death in Alzheimer’s and are the hallmarks of the disease.
Beta-amyloid plaques are also seen in some forms of LBD, cerebral amyloid angiopathy, and Parkinson’s disease dementia. They are also common in elderly individuals who do not have dementia.
Some, but not all, forms of frontotemporal disorders are tauopathies. Other forms of these disorders are associated with the buildup of the protein TDP-43. A mutation in a gene called progranulin, and another in a gene called C9orf72, can cause frontotemporal disorders with accumulation of TDP-43 in nerve cells.
In other dementias and some brain disorders, the protein synuclein becomes misshapen and forms harmful clumps inside neurons in different brain regions. Disorders in which synuclein builds up inside neurons are called synucleinopathies. Changes in synuclein and/or its function are the basis of LBD and other disorders such as multiple system atrophy. Multiple system atrophy is a progressive neurodegenerative disorder characterized by a combination of symptoms that affect both the autonomic nervous system (the part of the nervous system that controls involuntary action such as blood pressure or digestion) and movement. These changes cause parkinsonism, a condition resembling Parkinson’s disease.
Reversible Dementia-like Disorders and Conditions
Many conditions that cause dementia-like symptoms can be halted or even reversed with the 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.
Other Neurodegenerative Diseases and Conditions that Include Dementia or Dementia-like Symptoms
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 neurological 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.
Risk Factors for Dementia and Vascular Cognitive Impairment
The following risk factors may increase a person’s chance of developing one or more kinds of dementia. Some of these factors can be modified, while others cannot.
- Age. Advancing age is the best known risk factor for developing dementia.
- Hypertension. High blood pressure has been linked to cognitive decline, stroke, and types of dementia that damage the white matter regions of the brain. High blood pressure causes “wear-and-tear” to brain blood vessel walls called arteriosclerosis.
- Stroke. A single major stroke or a series of smaller strokes increases a person’s risk of developing vascular dementia. A person who has had a stroke is at an increased risk of having additional strokes, which further increases the risk of developing dementia.
- Alcohol use. Most studies suggest that regularly drinking large amounts of alcohol increases the risk of dementia. Specific dementias are associated with alcohol abuse, such as Wernicke-Korsakoff syndrome.
- Atherosclerosis. The accumulation of fats and cholesterol in the lining of arteries, coupled with an inflammatory process that leads to a thickening of the vessel walls (known as atherosclerosis), can lead to stroke, which raises the risk for vascular dementia.
- Diabetes. People with diabetes appear to have a higher risk for dementia. Poorly controlled diabetes is a risk factor for stroke and cardiovascular disease, which in turn increase the risk for vascular dementia.
- Down syndrome. Many people with Down syndrome develop symptoms of Alzheimer’s disease by the time they reach middle age.
- Genetics. The chance of developing a genetically linked form of dementia increases when more than one family member has the disorder. In many dementias, there can be a family history of a similar disease. In some cases, such as with the FTDs, having just one parent who carries a mutation increases the risk of inheriting the condition. A very small proportion of dementia is inherited.
- Head injury. An impact to the head can cause a traumatic brain injury, or TBI. Certain types of TBI, or repeated TBIs, can cause dementia and other severe cognitive problems.
- Parkinson’s disease. The degeneration and death of nerve cells in the brain in people with Parkinson’s disease can cause dementia and significant memory loss.
- Smoking. Smoking increases the risk of developing cardiovascular diseases that slow or stop blood from getting to the brain.
The National Academies of Sciences, Engineering, and Medicine recently released a report of the evidence on preventing dementia: www.ncbi.nlm.nih.gov/books/NBK436397.
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.
- Neurological 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.
- Presymptomatic 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.
Guidelines prepared by the National Institute on Aging and the Alzheimer’s Association focus on three stages of Alzheimer’s disease: (1) dementia due to Alzheimer’s, (2) mild cognitive impairment (MCI) due to Alzheimer’s, and (3) preclinical (presymptomatic) Alzheimer’s. (Presymptomatic identification is exclusively used as a research diagnosis at this point and has no relevance to routine clinical practice.) The guidelines also include biomarker tests used in studies to measure biological changes in the brain associated with Alzheimer’s disease and criteria for documenting and reporting Alzheimer’s-related changes observed during an autopsy.
Treatment and Management
There are currently no treatments to stop or slow dementia in neurodegenerative diseases. Some diseases that occur at the same time as dementia (such as diabetes and depression) can be treated. Other 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.
Medications are available to treat certain behavioral symptoms, as well as delusions, depression, muscle stiffness, and risk factors for vascular cognitive impairment such as high blood pressure. Always consult with a doctor, as some medications may make symptoms worse.
Alzheimer’s disease. Most drugs for dementia are used to treat symptoms in AD. One class of drugs, called cholinesterase inhibitors, can temporarily improve or stabilize memory and thinking skills in some people by increasing the activity of the cholinergic brain network—a subsystem in the brain that is highly involved with memory and learning. These drugs include donepezil, rivastigmine, and galantamine. The drug memantine is in another class of medications called NMDA receptor antagonists, which prevent declines in learning and memory. Memantine may be combined with a cholinesterase inhibitor for added benefits. These drugs are sometimes used to treat other dementias in which Alzheimer’s disease is believed to co-occur.
Frontotemporal disorders. There are no medications approved to treat or prevent FTD and most other types of progressive dementia. Sedatives, antidepressants, and other drugs used to treat Parkinson’s and Alzheimer’s symptoms may help manage certain symptoms and behavioral problems associated with the disorders.
Dementia with Lewy bodies. Medicines available for managing DLB are aimed at relieving symptoms such as gait and balance disturbances, stiffness, hallucinations, and delusions. Studies suggest that the cholinesterase inhibitor drugs for Alzheimer’s disease may offer some benefit to people with DLB.
Parkinson’s disease dementia. Some studies suggest that the cholinesterase inhibitors used to treat people with AD might improve cognitive, behavioral, and psychotic symptoms in people with Parkinson’s disease dementia. Unfortunately, many of the medications used to treat the motor symptoms of PD worsen cognitive problems. The U.S. Food and Drug Administration has approved rivastigmine (an Alzheimer’s drug) to treat cognitive symptoms in PDD.
Vascular contributions to cognitive impairment and dementia. This type of dementia is often managed with drugs to prevent strokes or reduce the risk of additional brain damage. Some studies suggest that drugs that improve memory in AD might benefit people with early vascular dementia. Treating the modifiable risk factors can help prevent additional stroke.
A team of therapists can help with maintaining physical movement, address speech, and swallowing issues, and help people learn new ways to handle the loss of skills with everyday tasks such as feeding oneself.
It is important to educate family, friends, and caregivers about a loved one’s medical issues. Also, in-person and online support groups available through many disease awareness and caregiver advocacy organizations can give families and other caregivers additional resources, as well as opportunities to share experiences and express concerns.