What Is Dementia?
Dementia is a general term for a decline in mental ability severe enough to interfere with daily life. Memory loss is an example. Alzheimer's is the most common type of
dementia.
About dementia
Dementia is not a specific disease. It's an overall term that describes a wide range of symptoms associated with a decline in memory or other thinking skills severe enough to reduce a person's ability to perform everyday activities. Alzheimer's disease accounts for 60 to 80 percent of cases. Vascular dementia, which occurs after a stroke, is the second most common dementia type. But there are many other conditions that can cause symptoms of dementia, including some that are reversible, such as thyroid problems and vitamin deficiencies.
Dementia is often incorrectly referred to as "senility" or "senile dementia," which reflects the formerly widespread but incorrect belief that serious mental decline is a normal part of aging.
Dementia is a general term for loss of memory and other mental abilities severe enough to interfere with daily life. It is caused by physical changes in the brain.
Type of Dementia
Alzheimer's disease
Alzheimer's is a type of dementia that causes problems with memory, thinking and behavior. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks.
Alzheimer's is the most common form of dementia, a general term for memory loss and other intellectual abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 60 to 80 percent of dementia cases.
Alzheimer's is not a normal part of aging, although the greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. But Alzheimer's is not just a disease of old age. Up to 5 percent of people with the disease have early onset Alzheimer's (also known as younger-onset), which often appears when someone is in their 40s or 50s.
Alzheimer's worsens over time. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a
conversation and respond to their environment. Alzheimer's is the sixth leading cause of death in the United States. Those with Alzheimer's live an average of eight years after their symptoms become noticeable to others, but survival can range from four to 20 years, depending on age and other health conditions.
Ten Warning Signs of Alzheimer’s
1 Memory Loss that disrupts daily life - One of the most common signs of Alzheimer's is memory loss, especially forgetting recently learned information. Others include forgetting important dates or events; asking for the same information over and over; increasingly needing to rely on memory aids (e.g., reminder notes or electronic devices) or family members for things they used to handle on their own.
2 Challenges in planning or solving problems - Some people may
experience changes in their ability to develop and follow a plan or work with numbers. They may have trouble following a familiar recipe or keeping track of monthly bills. They may have difficulty concentrating and take much longer to do things than they did before. What's a typical age-related change? Making occasional errors when balancing a checkbook.
3 Difficulty completing familiar tasks at home, at work or at leisure - People with Alzheimer's often find it hard to complete daily tasks. Sometimes, people may have trouble driving to a familiar location, managing a budget at work or remembering the rules of a favorite game. What's a typical age-related change? Occasionally needing help to use the settings on a microwave or to record a television show. 4 Confusion with time or place - People with Alzheimer's can lose track
of dates, seasons and the passage of time. They may have trouble understanding something if it is not happening immediately.
Sometimes they may forget where they are or how they got there. What's a typical age-related change? Getting confused about the day of the week but figuring it out later.
5 Trouble understanding visual images and spatial relationships - For some people, having vision problems is a sign of Alzheimer's. They may have difficulty reading, judging distance and determining color or contrast, which may cause problems with driving. . What's a typical age-related change? Vision changes related to cataracts.
6 New Problems with words in speaking or writing - People with
Alzheimer's may have trouble following or joining a conversation. They may stop in the middle of a conversation and have no idea how to continue or they may repeat themselves. They may struggle with vocabulary, have problems finding the right word or call things by the
wrong name (e.g., calling a "watch" a "hand-clock"). What's a typical age-related change? Sometimes having trouble finding the right word. 7 Misplacing things and losing the ability to retrace steps - A person with
Alzheimer's disease may put things in unusual places. They may lose things and be unable to go back over their steps to find them again. Sometimes, they may accuse others of stealing. This may occur more frequently over time. What's a typical age-related change?
Misplacing things from time to time and retracing steps to find them. 8 Decreased or poor judgment - People with Alzheimer's may experience
changes in judgment or decision-making. For example, they may use poor judgment when dealing with money, giving large amounts to telemarketers. They may pay less attention to grooming or keeping themselves clean. What's a typical age-related change? Making a bad decision once in a while.
9 Withdrawl from work or social activities - A person with Alzheimer's may start to remove themselves from hobbies, social activities, work projects or sports. They may have trouble keeping up with a favorite sports team or remembering how to complete a favorite hobby. They may also avoid being social because of the changes they have experienced. What's a typical age-related change? Sometimes feeling weary of work, family and social obligations.
10 Changes in mood and personality - The mood and personalities of people with Alzheimer's can change. They can become confused, suspicious, depressed, fearful or anxious. They may be easily upset at home, at work, with friends or in places where they are out of their comfort zone. What's a typical age-related change? Developing very specific ways of doing things and becoming irritable when a routine is disrupted.
Typical age-related memory loss and other changes compared to Alzheimer's
Alzheimer’s Typical Age related change
Poor judgment and decision making Making a bad decision once in a while
Inability to manage a budget Missing a monthly payment Losing track of the date or the season Forgetting which day it is and
remembering later
Difficulty having a conversation Sometimes forgetting which word to use
Misplacing things and being unable to retrace
steps to find them Losing things from time to time
Stages of Alzheimer’s disease
Stage 1: No impairment (normal function)
The person does not experience any memory problems. An interview with a medical professional does not show any evidence of symptoms of dementia.
Stage 2: Very mild cognitive decline (may be normal age-related changes or earliest signs of Alzheimer's disease)
The person may feel as if he or she is having memory lapses — forgetting familiar words or the location of everyday objects. But no symptoms of dementia can be detected during a medical examination or by friends, family or co-workers.
Stage 3:
Mild cognitive decline (early-stage Alzheimer's can be diagnosed in some, but not all, individuals with these symptoms)
Friends, family or co-workers begin to notice difficulties. During a detailed medical interview, doctors may be able to detect problems in memory or concentration. Common stage 3 difficulties include:
- Noticeable problems coming up with the right word or name - Trouble remembering names when introduced to new people
- Having noticeably greater difficulty performing tasks in social or work settings
- Forgetting material that one has just read - Losing or misplacing a valuable object
- Increasing trouble with planning or organizing
Stage 4:
Moderate cognitive decline
(Mild or early-stage Alzheimer's disease)
At this point, a careful medical interview should be able to detect clear-cut symptoms in several areas:
• Forgetfulness of recent events
• Impaired ability to perform challenging mental arithmetic — for example, counting backward from 100 by 7s
• Greater difficulty performing complex tasks, such as planning dinner for guests, paying bills or managing finances
• Forgetfulness about one's own personal history
• Becoming moody or withdrawn, especially in socially or mentally challenging situations
Stage 5: Moderately severe cognitive decline (Moderate or mid-stage Alzheimer's disease)
Gaps in memory and thinking are noticeable, and individuals begin to need help with day-to-day activities. At this stage, those with Alzheimer's may:
• Be unable to recall their own address or telephone number or the high school or college from which they graduated
• Become confused about where they are or what day it is
• Have trouble with less challenging mental arithmetic; such as counting backward from 40 by subtracting 4s or from 20 by 2s
• Need help choosing proper clothing for the season or the occasion • Still remember significant details about themselves and their family • Still require no assistance with eating or using the toilet
Stage 6: Severe cognitive decline
(Moderately severe or mid-stage Alzheimer's disease)
Memory continues to worsen, personality changes may take place and individuals need extensive help with daily activities. At this stage, individuals may:
• Lose awareness of recent experiences as well as of their surroundings • Remember their own name but have difficulty with their personal
history
• Distinguish familiar and unfamiliar faces but have trouble remembering the name of a spouse or caregiver
• Need help dressing properly and may, without supervision, make mistakes such as putting pajamas over daytime clothes or shoes on the wrong feet
• Experience major changes in sleep patterns — sleeping during the day and becoming restless at night
• Need help handling details of toileting (for example, flushing the toilet, wiping or disposing of tissue properly)
• Have increasingly frequent trouble controlling their bladder or bowels • Experience major personality and behavioral changes, including
suspiciousness and delusions (such as believing that their caregiver is an impostor)or compulsive, repetitive behavior like hand-wringing or tissue shredding
• Tend to wander or become lost
Stage 7: Very severe cognitive decline
(Severe or late-stage Alzheimer's disease)
environment, to carry on a conversation and, eventually, to control movement. They may still say words or phrases.
At this stage, individuals need help with much of their daily personal care, including eating or using the toilet. They may also lose the ability to smile, to sit without support and to hold their heads up. Reflexes become abnormal. Muscles grow rigid. Swallowing impaired.
Alzheimer's has no current cure, but treatments for symptoms are available and research continues. Although current Alzheimer's treatments cannot stop Alzheimer's from progressing, they can temporarily slow the worsening of dementia symptoms and improve quality of life for those with Alzheimer's and their caregivers. Today, there is a worldwide effort under way to find better ways to treat the disease, delay its onset, and prevent it from developing.
Symptoms: Difficulty remembering recent conversations, names or events is often an early clinical symptom; apathy and depression are also often early symptoms. Later symptoms include impaired communication, poor judgment, disorientation, confusion, behavior changes and difficulty speaking, swallowing and walking.
New criteria and guidelines for diagnosing Alzheimer's were published in 2011 recommending that Alzheimer's disease be considered a disease with three stages, beginning well before the development of symptoms.
Brain changes: Hallmark abnormalities are deposits of the protein fragment
beta-amyloid (plaques) and twisted strands of the protein tau (tangles) as well as evidence of nerve cell damage and death in the brain.
Alzheimer's disease is a progressive brain disorder that damages and eventually destroys brain cells, leading to memory loss and changes in thinking and other brain functions. It usually develops slowly and gradually gets worse as brain function declines and brain cells eventually wither and die. Ultimately, Alzheimer's is fatal, and currently, there is no cure.
But neuroscience research efforts are under way to develop effective treatments and ways to prevent the disease. Researchers are also working to develop better ways to care for affected people and better ways to support their families, friends and
caregivers. The Alzheimer's Association is moving these research efforts forward by funding scientists who are searching for more answers and new treatments,
collaborating with stakeholders, fostering worldwide partnerships among scientists, and raising the visibility of Alzheimer's as a global health challenge.
The role of plaques and tangles
Two abnormal structures called plaques and tangles are prime suspects in damaging and killing nerve cells.
Plaques are deposits of a protein fragment called beta-amyloid (BAY-tuh AM-uh-loyd) that build up in the spaces between nerve cells.
Tangles are twisted fibers of another protein called tau (rhymes with “wow”) that build up inside cells.
Though most people develop some plaques and tangles as they age, those with Alzheimer's tend to develop far more. They also tend to develop them in a predictable pattern, beginning in areas important for memory before spreading to other regions. Scientists do not know exactly what role plaques and tangles play in Alzheimer's disease. Most experts believe they somehow play a critical role in blocking
communication among nerve cells and disrupting processes that cells need to survive. It's the destruction and death of nerve cells that causes memory failure, personality changes, problems carrying out daily activities and other symptoms of Alzheimer's disease.
Vascular Dementia
Previously known as multi-infarct or post-stroke dementia, vascular dementia is less common as a sole cause of dementia than Alzheimer’s, accounting for about 10 percent of dementia cases.
Symptoms: Impaired judgment or ability to make decisions, plan or organize is more likely to be the initial symptom, as opposed to the memory loss often associated with the initial symptoms of Alzheimer's. Occurs because of brain injuries such as
microscopic bleeding and blood vessel blockage. The location, number and size of the brain injury determines how the individual's thinking and physical functioning are affected.
Brain changes: Brain imaging can often detect blood vessel problems implicated in vascular dementia. In the past, evidence for vascular dementia was used to exclude a diagnosis of Alzheimer's disease (and vice versa). That practice is no longer considered consistent with pathologic evidence, which shows that the brain changes of several types of dementia can be present simultaneously. When any two or more types of dementia are present at the same time, the individual is considered to have "mixed dementia"
Inadequate blood flow can damage and eventually kill cells anywhere in the body. The brain has one of the body's richest networks of blood vessels and is especially
vulnerable.
In vascular dementia, changes in thinking skills sometimes occur suddenly following strokes that block major brain blood vessels. Thinking problems also may begin as mild changes that worsen gradually as a result of multiple minor strokes or other conditions that affect smaller blood vessels, leading to cumulative damage. A growing number of experts prefer the term "vascular cognitive impairment (VCI)" to "vascular dementia" because they feel it better expresses the concept that vascular thinking changes can range from mild to severe.
Vascular brain changes often coexist with changes linked to other types of dementia, including Alzheimer's disease and dementia with Lewy bodies. Several studies have found that vascular changes and other brain abnormalities may interact in ways that increase the likelihood of dementia diagnosis.
Vascular dementia is widely considered the second most common cause of dementia after Alzheimer's disease, accounting for 10 percent of cases. Many experts believe that vascular dementia remains underdiagnosed — like Alzheimer's disease — even though it's recognized as common.
Symptoms can vary widely, depending on the severity of the blood vessel damage and the part of the brain affected. Memory loss may or may not be a significant symptom depending on the specific brain areas where blood flow is reduced.
Vascular dementia symptoms may be most obvious when they happen soon after a major stroke. Sudden post-stroke changes in
thinking and perception may include: • Confusion
• Disorientation
• Trouble speaking or understanding speech • Vision loss
These changes may happen at the same time as more familiar physical stroke symptoms, such as a sudden headache, difficulty walking, or numbness or paralysis on one side of the face or the body.
Multiple small strokes or other conditions that affect blood vessels and nerve fibers deep inside the brain may cause more gradual thinking changes as
damage accumulates. Common early signs of widespread small vessel disease include impaired planning and judgment; uncontrolled laughing and
crying; declining ability to pay attention; impaired function in social situations; and difficulty finding the right words.
Diagnosis
Because vascular cognitive impairment may often go unrecognized, many experts recommend professional screening with brief tests to assess memory, thinking and reasoning for everyone considered to be at high risk for this disorder. Individuals at highest risk include those who have had a stroke or a transient ischemic attack (TIA, also known as a "ministroke"). Additional high-risk groups include those with high blood pressure, high cholesterol, or other risk factors for heart or blood vessel disease.
Professional screening for depression is also recommended for high-risk groups. Depression commonly coexists with brain vascular disease and can contribute to cognitive symptoms.
If brief screening tests suggest changes in thinking or reasoning, a more detailed assessment is needed. Core elements of a workup for vascular dementia typically include:
• A thorough medical history, including family history of dementia • Evaluation of independent function and daily activities
• Input from a family member or trusted friend
• In-office neurological examination assessing function of nerves and reflexes, movement, coordination, balance and senses
• Laboratory tests including blood tests and brain imaging
According to a 2011 scientific statement issued by the American Heart Association (AHA) and the American Stroke Association (ASA), and endorsed by the Alzheimer's Association and the American Academy of Neurology (AAN), the following three criteria suggest the greatest likelihood that mild cognitive impairment (MCI) or dementia is caused by vascular changes:
1. The diagnosis of dementia or mild cognitive impairment is confirmed by
tests that provide detailed evaluation of specific thinking skills such as judgment, planning, problem-solving, reasoning and memory
2. There is brain imaging evidence, usually with magnetic resonance imaging (MRI), showing evidence of either:
a. A recent stroke, or
b. Other brain blood vessel changes whose severity and pattern of affected tissue are consistent with the types of impairment documented in
neurocognitive testing
3. There is no evidence that factors other than vascular changes are contributing to cognitive decline.
The guidelines also discuss cases where the diagnosis may be less clear-cut, such as the common situation where vascular changes coexist with brain changes associated with other types of dementia.
Causes and risks
As with Alzheimer's disease, advancing age is a major risk factor for vascular cognitive impairment or dementia. Additional risk factors are the same ones that raise risk for heart problems, stroke and other diseases that affect blood vessels. Many of these vascular factors also raise risk for Alzheimer's. The following strategies may reduce your risk of diseases that affect your heart and blood vessels — and also may help protect your brain: • Don't smoke
• Keep your blood pressure, cholesterol and blood sugar within recommended limits
• Eat a healthy, balanced diet • Exercise
• Maintain a healthy weight • Limit alcohol consumption
Dementia with Lewy Bodies (DLB)
Symptoms: People with dementia with Lewy bodies often have memory loss and thinking problems common in Alzheimer's, but are more likely than people with
Alzheimer's to have initial or early symptoms such as sleep disturbances, well-formed visual hallucinations, and muscle rigidity or other parkinsonian movement features.
Brain changes: Lewy bodies are abnormal aggregations (or clumps) of the protein alpha-synuclein. When they develop in a part of the brain called the cortex, dementia can result. Alpha-synuclein also aggregates in the brains of people with Parkinson's disease, but the aggregates may appear in a pattern that is different from dementia with Lewy bodies.
The brain changes of dementia with Lewy bodies alone can cause dementia, or they can be present at the same time as the brain changes of Alzheimer's disease and/or vascular dementia, with each abnormality contributing to the development of dementia. When this happens, the individual is said to have "mixed dementia."
Most experts estimate that dementia with Lewy bodies is the third most common cause of dementia after Alzheimer's disease and vascular dementia, accounting for 10 to 25 percent of cases.
The hallmark brain abnormalities linked to DLB are named after Frederick H. Lewy, M.D., the neurologist who discovered them while working in Dr. Alois Alzheimer's laboratory during the early 1900s. Alpha-synuclein protein, the chief component of Lewy bodies, is found widely in the brain, but its normal function isn't yet known.
Lewy bodies are also found in other brain disorders, including
Alzheimer's disease and Parkinson's disease dementia. Many people with Parkinson's eventually develop problems with thinking and reasoning, and many people with DLB experience movement
symptoms, such as hunched posture, rigid muscles, a shuffling walk and trouble initiating movement.
This overlap in symptoms and other evidence suggest that DLB, Parkinson's disease and Parkinson's disease dementia may be linked to the same underlying abnormalities in how the brain processes the protein alpha-synuclein. Many people with both DLB and Parkinson's dementia also have plaques and tangles
Symptoms
Symptoms of dementia with Lewy bodies include: • Changes in thinking and reasoning
• Confusion and alertness that varies significantly from one time of day to another or from one day to the next
• Parkinson's symptoms, such as a hunched posture, balance problems and rigid muscles
• Visual hallucinations • Delusions
• Trouble interpreting visual information
• Acting out dreams, sometimes violently, a problem known as rapid eye movement (REM) sleep disorder
• Malfunctions of the "automatic" (autonomic) nervous system • Memory loss that may be significant but less prominent than in
Alzheimer's
Diagnosis
Key differences between Alzheimer's and DLB
Memory loss tends to be a more prominent symptom in early Alzheimer's than in early DLB, although advanced DLB may cause memory problems in addition to its more typical effects on judgment, planning and visual perception.
Movement symptoms are more likely to be an important cause of disability early in DLB than in Alzheimer's, although
Alzheimer's can cause problems with walking, balance and getting around as it progresses to moderate and severe stages. Hallucinations, delusions, and misidentification of familiar people are significantly more frequent in early-stage DLB than in Alzheimer's.
REM sleep disorder is more common in early DLB than in Alzheimer's.
Disruption of the autonomic nervous system, causing a blood
pressure drop on standing, dizziness, falls and urinary incontinence, is much more common in early DLB than in Alzheimer's.
As with other types of dementia there is no single test that can conclusively diagnose dementia with Lewy bodies. Today, DLB is a "clinical" diagnosis, which means it represents a doctor's best
professional judgment about the reason for a person's symptoms. The only way to conclusively diagnose DLB is through a postmortem autopsy.
Many experts now believe that DLB and Parkinson's disease dementia are two different expressions of the same underlying problems with brain processing of the protein alpha-synuclein. But most experts recommend continuing to diagnose DLB and Parkinson's dementia as separate disorders.
• The diagnosis is DLB when:
o Dementia symptoms consistent with DLB develop first o When both dementia symptoms and movement symptoms
are present at the time of diagnosis
o When movement symptoms develop within a year after DLB diagnosis.
• The diagnosis is Parkinson's disease dementia when a person is originally diagnosed with Parkinson's based on movement
symptoms, and dementia symptoms don't appear until a year or more later.
Since Lewy bodies tend to coexist with Alzheimer's brain changes, it may sometimes be hard to distinguish DLB from Alzheimer's disease, especially in the early stages.
Frontotemperal Dementia
Includes dementias such as behavioral variant FTD (bvFTD), primary progressive aphasia, Pick's disease and progressive supranuclear palsy.
Symptoms: Typical symptoms include changes in personality and behavior and difficulty with language. Nerve cells in the front and side regions of the brain are especially affected.
Brain changes: No distinguishing microscopic abnormality is linked to all cases. People with FTD generally develop symptoms at a younger age (at about age 60) and survive for fewer years than those with Alzheimer's.
Includes dementias such as behavioral variant FTD (bvFTD), primary progressive aphasia, Pick's disease and progressive supranuclear palsy.
The cell damage caused by frontotemporal dementia leads to tissue shrinkage and reduced function in the brain's frontal and temporal lobes, which control planning and judgment; emotions, speaking and understanding speech; and certain types of
movement.
FTD includes a range of specific disorders with different core symptoms. But there's significant symptom overlap, especially as these disorders progress. The disorders grouped under FTD fall into three broad categories (discussed below). Scientists have identified a range of microscopic brain abnormalities implicated in FTD. The overall term for the brain cell damage and tissue shrinkage associated with FTD is frontotemporal lobar degeneration.
FTD used to be called Pick's disease after Arnold Pick, a physician who in 1892 first described a patient with distinct symptoms affecting language. Some doctors still use the term "Pick's disease." Other terms you may see used to describe FTD include frontotemporal disorders, frontotemporal degeneration and frontal lobe disorders. FTD was once considered rare, but it's now thought to account for up to 10 to 15 percent of all dementia cases. It's still believed to be less common than Alzheimer's disease, vascular dementia and Lewy body dementia.
In those younger than age 65, FTD may account for up to 20 to 50 percent of dementia cases. People usually develop FTD in their 50s or early 60s, making the disorder relatively more common in this younger age group
Symptoms
Experts group frontotemporal dementia into three main categories. Initially, these groups tend to cause different core symptoms based on the first parts of the brain's frontal or temporal lobes they affect. But there's increasing overlap in symptoms as these disorders progress.
Symptoms related to the three types of FTD include:
• Behavioral variant frontotemporal dementia (bvFTD) takes its greatest toll on personality and behavior. It may begin with subtle changes that may be mistaken for depression. As bvFTD progresses people often develop disinhibition, a
striking loss of restraint in personal relations and social life.
• Primary progressive aphasia (PPA) affects language skills in early stages, but often also affects behavior as it advances. The two chief forms of PPA have somewhat different symptoms:
o In semantic dementia, people speak easily, but their words convey less and less meaning. They tend to use broad general terms, such as
"animal" when they mean "cat." Language comprehension also declines. o In progressive nonfluent aphasia, people lose their ability to generate
words easily, and their speech becomes halting, "tongue-tied" and ungrammatical. Ability to read and write also may be impaired.
• FTD movement disorders affect certain involuntary, automatic muscle functions. These disorders also may impair language and behavior. The two primary FTD movement disorders are:
o Corticobasal degeneration (CBD), which causes shakiness, lack of coordination, and muscle rigidity and spasms.
o Progressive supranuclear palsy (PSP), which causes walking and balance problems, frequent falls and muscle stiffness, especially in the neck and upper body. It also affects eye movements.
Diagnosis
There is no single test — or any combination of tests — that can conclusively diagnose frontotemporal dementia. FTD is a "clinical" diagnosis representing a doctor's best professional judgment about the reason for a person's symptoms. Magnetic resonance imaging (MRI) often plays a key role in diagnosis because it can detect shrinkage in the brain's frontal and temporal lobes, which is a hallmark of FTD.
In some cases, it may be hard to distinguish FTD from Alzheimer's disease. In the future, tests to detect specific protein abnormalities linked to Alzheimer's and FTD may help clarify the diagnosis in difficult cases.
Key Differences Between FTD and Alzheimer's
• Age at diagnosis may be an important clue. Most people with FTD are diagnosed in their 50s and early 60s. Only about 10 percent are diagnosed after age 70. Alzheimer's, on the other hand, grows more common with increasing age.
• Memory loss tends to be a more prominent symptom in early Alzheimer's than in early FTD, although advanced FTD often causes memory loss in addition to its more characteristic effects on behavior and language.
• Behavior changes are often the first noticeable symptoms in bvFTD, the most common form of FTD. Behavior changes are also common as Alzheimer's progresses, but they tend to occur later in the disease.
• Problems with spatial orientation — for example, getting lost in familiar places — are more common in Alzheimer's than in FTD.
• Problems with speech. Although people with Alzheimer's may have trouble thinking of the right word or remembering names, they tend to have less difficulty making sense when they speak, understanding the speech of others, or reading than those with FTD.
Hallucinations and delusions are relatively common as Alzheimer's progresses, but relatively uncommon in FTD.
Causes and risks
Researchers have identified abnormal deposits of several proteins inside the brain cells of those who died with frontotemporal dementia. Scientists have not yet learned what causes these protein abnormalities or solved the mystery of why the damage
associated with FTD targets the brain's frontal and temporal lobes.
The only known risk factor for FTD is a family history of the disease. Scientists have found several genes linked to FTD.
Recent research suggests a possible connection between FTD and Lou Gehrig's disease, also known as amyotrophic lateral sclerosis (ALS) and motor neuron disease. Although ALS primarily affects nerves controlling voluntary movement, many people with ALS also develop symptoms affecting their behavior or language, and some people with FTD develop ALS.
Parkinson’s Disease
As Parkinson's disease progresses, it often results in a progressive dementia similar to dementia with Lewy bodies or Alzheimer's.
Symptoms: Problems with movement are a common symptom early in the disease. If dementia develops, symptoms are often similar to dementia with Lewy bodies.
Brain changes: Alpha-synuclein clumps are likely to begin in an area deep in the brain called the substantia nigra. These clumps are thought to cause degeneration of the nerve cells that produce dopamine.
As Parkinson's disease progresses, it often results in a progressive dementia similar to dementia with Lewy bodies or Alzheimer's.
The brain changes caused by Parkinson's disease begin in a region that plays a key role in movement. As Parkinson's brain changes gradually spread, they often begin to affect mental functions, including memory and the ability to pay attention, make sound judgments and plan the steps needed to complete a task.
The key brain changes linked to Parkinson's disease and Parkinson's disease dementia are abnormal microscopic deposits composed chiefly of alpha-synuclein, a protein that's found widely in the brain but whose normal function isn't yet known. The deposits are called "Lewy bodies".
Lewy bodies are also found in several other brain disorders, including dementia with Lewy bodies (DLB). Evidence suggests that dementia with Lewy bodies, Parkinson's disease and Parkinson's disease dementia may be linked to the same underlying abnormalities in brain processing of alpha-synuclein.
Another complicating factor is that many people with both dementia with Lewy bodies and Parkinson's disease dementia also have plaques and tangles — hallmark brain changes linked to Alzheimer's disease.
Parkinson's disease is a fairly common neurological disorder in older adults, estimated to affect nearly 2 percent of those older than age 65. The National Parkinson
Foundation estimates that 1 million Americans have Parkinson's disease. It is estimated that 50 to 80 percent of those with Parkinson's disease eventually experience
Parkinson's disease dementia. Symptoms
Parkinson's disease dementia is a decline in thinking and reasoning that develops in someone diagnosed with Parkinson's disease at least a year earlier. Common symptoms include:
• Changes in memory, concentration and judgment • Trouble interpreting visual information
• Muffled speech • Visual hallucinations
• Delusions, especially paranoid ideas • Depression
• Irritability and anxiety
• Sleep disturbances, including excessive daytime drowsiness and rapid eye movement (REM) sleep disorder
Diagnosis
As with other types of dementia there is no single test — or any combination of tests — that conclusively determines that a person has Parkinson's disease dementia.
Many experts now believe that Parkinson's disease dementia and dementia with Lewy bodies are two different expressions of the same underlying problems with brain processing of the protein alpha-synuclein. But most experts recommend continuing to diagnose dementia with Lewy bodies and Parkinson's dementia as separate disorders. Guidelines for diagnosing Parkinson's disease dementia and dementia with Lewy bodies are:
• The diagnosis is Parkinson's disease dementia when a person is originally diagnosed with Parkinson's based on movement symptoms and dementia symptoms don't appear until a year or more later
• The diagnosis is dementia with Lewy bodies when:
o Dementia symptoms consistent with dementia with Lewy bodies develop first
o When both dementia symptoms and movement symptoms are present at the time of diagnosis
o When movement symptoms develop within a year of a dementia with Lewy bodies diagnosis
Diagnosis
As with other types of dementia there is no single test — or any combination of tests — that conclusively determines that a person has Parkinson's disease dementia.
Many experts now believe that Parkinson's disease dementia and dementia with Lewy bodies are two different expressions of the same underlying problems with brain processing of the protein alpha-synuclein. But most experts recommend continuing to diagnose dementia with Lewy bodies and Parkinson's dementia as separate disorders. Guidelines for diagnosing Parkinson's disease dementia and dementia with Lewy bodies are:
• The diagnosis is Parkinson's disease dementia when a person is originally diagnosed with Parkinson's based on movement symptoms and dementia symptoms don't appear until a year or more later
• The diagnosis is dementia with Lewy bodies when:
o Dementia symptoms consistent with dementia with Lewy bodies develop first
o When both dementia symptoms and movement symptoms are present at the time of diagnosis
o When movement symptoms develop within a year of a dementia with Lewy bodies diagnosis
Causes and risks
Certain factors at the time of Parkinson's diagnosis may increase future dementia risk, including older age, greater severity of motor symptoms, and having mild cognitive impairment (MCI).
Additional risk factors may include:
• Hallucinations in a person who doesn't yet have other dementia symptoms • Excessive daytime sleepiness
• Parkinson's symptom pattern known as postural instability and gait disturbance (PIGD), which includes "freezing" in mid-step, difficulty initiating movement, shuffling, problems with balance and falling
Treatment and outcomes
There are no treatments to slow or stop the brain cell damage caused by Parkinson's disease dementia. Current strategies focus on helping symptoms.
If your treatment plan includes medications, it's important to work closely with your physician to identify the drugs that work best for you and the most effective doses. Treatment considerations involving medications include the following issues: :
Cholinesterase inhibitors drugs are the current mainstay for treating thinking changes in Alzheimer's. They also may help Parkinson's disease dementia symptoms.
Antipsychotic drugs should be used with extreme caution in Parkinson's disease dementia. Although physicians sometimes prescribe these drugs for behavioral symptoms that can occur in Alzheimer's, they may cause serious side effects in as many as 50 percent of those with Parkinson's disease dementia and dementia with Lewy bodies. Side effects may include sudden changes in consciousness, impaired swallowing, acute confusion, episodes of delusions or hallucinations, or appearance or worsening of Parkinson's symptoms. L-dopa may be prescribed to treat Parkinson's movement symptoms. However, it can sometimes aggravate hallucinations and confusion in those with Parkinson's dementia or dementia with Lewy bodies.
• Antidepressants may be used to treat depression, which is common in both Parkinson's disease dementia and dementia with Lewy bodies. The most commonly used antidepressants are selective serotonin reuptake inhibitors (SSRIs).
Clonazepam may be prescribed to treat REM sleep disorder. Creutzfeldt-Jakob disease
CJD is the most common human form of a group of rare, fatal brain disorders affecting people and certain other mammals. Variant CJD (“mad cow disease”) occurs in cattle, and has been transmitted to people under certain circumstances.
Symptoms: Rapidly fatal disorder that impairs memory and coordination and causes behavior changes.
Brain changes: Results from misfolded prion protein that causes a "domino effect" in which prion protein throughout the brain misfolds and
thus malfunctions.
Prion diseases, such as Creutzfeldt-Jakob disease, occur when prion protein, which is found throughout the body but whose normal function isn't yet known, begins folding into an abnormal three-dimensional shape. This shape change gradually triggers prion protein in the brain to fold into the same abnormal shape.
Through a process scientists don't yet understand, misfolded prion protein destroys brain cells. Resulting damage leads to rapid decline in thinking and reasoning as well as involuntary muscle movements, confusion, difficulty walking and mood changes.
Sporadic CJD develops spontaneously for no known reason. It accounts for 85 percent of cases. On average, sporadic CJD first appears between ages 60 and 65.
Familial CJD is a heredity form caused by certain changes in the prion protein gene. These genetic changes are "dominant," meaning that anyone who inherits a CJD gene from an affected parent will also develop the disorder. Familial CJD accounts for about 10 to 15 percent of cases.
Infectious CJD is an especially rare form of CJD and results from exposure to an external source of
abnormal prion protein. These sources are estimated to account for about 1 percent of CJD cases. The two most common outside sources are:
Medical procedures involving instruments used in neurosurgery, growth hormone from human sources or certain transplanted human tissues. The risk of CJD from medical procedures has been greatly reduced by improved sterilization techniques, new single-use instruments and synthetic sources of growth hormone.
Meat or other products from cattle infected with bovine spongiform encephalopathy ("mad cow disease"), recognized in the mid-1990s as the cause of variant CJD (vCJD).
Scientists traced this new type of CJD to consumption of beef from cattle whose feed included processed brain tissue from other animals.
Symptoms
Specific Creutzfeldt-Jakob disease symptoms experienced by an individual and the order in which they appear can differ significantly. Some common symptoms include:
• Depression
• Agitation, apathy and mood swings
• Rapidly worsening confusion, disorientation, and problems with memory, thinking, planning and judgment
• Difficulty walking
• Muscle stiffness, twitches and involuntary jerky movements
Rapid symptom progression is one of the most important clues that a person may have Creutzfeldt-Jakob disease.
There is no single test — or any combination of tests — that can conclusively diagnose sporadic CJD in a living person, but the following tests may help determine whether an individual has CJD:
Electroencephalogram (EEG)measures the brain's patterns of electrical activity similar to the way an electrocardiogram (ECG) measures the heart's electrical activity.
Brain magnetic resonance imaging (MRI) can detect certain brain changes consistent with CJD.
Lumbar puncture (spinal tap) tests spinal fluid for the presence of certain proteins. Causes and risks
Sporadic Creutzfeldt-Jakob disease has no known cause. Most scientists believe the disease begins when prion protein somewhere in the brain spontaneously misfolds, triggering a "domino effect" that misfolds prion protein throughout the brain. Genetic variation in the prion protein gene may affect risk of this spontaneous misfolding. Mutations in the prion protein gene also may play a yet-to-be-determined role in making people susceptible to infectious CJD from external sources. Scientists don't yet know the why infectious CJD seems to be transmitted through such a limited number of external sources. Researchers have found no evidence that the abnormal protein is commonly transmitted through sexual activity or blood transfusions.
Familial CJD is caused by variations in the prion protein gene that guarantee an individual will develop CJD. Researchers have identified more than 50 prion protein mutations in those with inherited CJD. Genetic testing can determine whether family
members at risk have inherited a CJD-causing mutation. Experts strongly recommend professional genetic counseling both before and after genetic testing for hereditary CJD. Treatment and outcomes
There is no treatment that can slow or stop the underlying brain cell destruction caused by Creutzfeldt-Jakob disease and other prion diseases. Various drugs have been tested but have not shown any benefit. Clinical studies of potential CJD treatments are
complicated by the rarity of the disease and its rapid progression.
Current therapies focus on treating symptoms and on supporting individuals and
families coping with CJD. Doctors may prescribe painkillers such as opiates to treat pain if it occurs. Muscle stiffness and twitching may be treated with muscle-relaxing
medications or antiseizure drugs. In the later stages of the disease, individuals with CJD become completely dependent on others for their daily needs and comfort.
CJD progresses rapidly. Those affected lose their ability to move or speak and require full-time care to meet their daily needs. An estimated 90 percent of those diagnosed with sporadic CJD die within one year. Those affected by familial CJD tend to develop the disorder at an earlier age and survive somewhat longer than those with the sporadic form, as do those diagnosed with vCJD. Scientists have not yet learned the reason for these differences in survival.
Normal pressure hydrocephalus
Symptoms: Symptoms include difficulty walking, memory loss and inability to control urination.
Brain changes: Caused by the buildup of fluid in the brain. Can sometimes be corrected with surgical installation of a shunt in the brain to drain excess fluid.
Normal pressure hydrocephalus occurs when excess cerebrospinal fluid accumulates in the brain's ventricles, which are hollow fluid-filled chambers. NPH is called "normal pressure" because despite the excess fluid, cerebrospinal fluid pressure as measured during a spinal tap is often normal. As brain ventricles enlarge with the excess
cerebrospinal fluid, they can disrupt and damage nearby brain tissue, causing symptoms of NPH.
NPH primarily affects people in their 60s and 70s. Scientists aren't certain how many older adults have this disorder because common symptoms of NPH are also common in other brain disorders.
Symptoms
The following symptoms are considered hallmarks of normal pressure hydrocephalus: • Difficulty walking that's sometimes compared to the way a person walks "on a
boat," with the body bent forward, legs held wide apart and feet moving as if they're "glued to the deck."
• Decline in thinking skills that includes overall slowing of thought processes, apathy, impaired planning and decision-making, reduced concentration and changes in personality and behavior.
• Loss of bladder control, which tends to appear somewhat later in the disease than difficulty walking and cognitive decline.
Diagnosis
There is no single test to determine if someone has normal pressure hydrocephalus. And even though the three hallmark symptoms listed above are considered the "classic" signs of this disorder, not everyone with NPH has all of these symptoms.
Brain imaging to detect enlargement of the ventricles, often with magnetic resonance imaging (MRI), plays a key role in diagnosing NPH. Several brain disorders, including Alzheimer's disease, can cause overall brain tissue shrinkage that makes the ventricles look larger than normal. In NPH, although the ventricles are enlarged, brain tissue may not appear shrunken.
Because the symptoms of NPH may overlap with those of Alzheimer's and other dementias, experts recommend that a person with suspected NPH undergo
examination by a neurologist with extensive experience evaluating brain disorders that affect movement, thinking skills and physical functions.
If symptoms and an MRI strongly suggest NPH, a large-volume spinal tap may be used to identify those who may benefit from a shunt. In this procedure, doctors remove a larger-than-usual amount of spinal fluid, and then observe the person for 30 to 60 minutes to note any improvements in walking or thinking and reasoning. Most people originally suspected of having NPH do not improve following a CSF removal test. Causes and risks
In some cases, normal pressure hydrocephalus is caused by other brain disorders such as hemorrhages, infections or inflammation. But in most cases, the fluid buildup
happens for unknown reasons. Treatment and outcomes
Researchers have not found effective nonsurgical treatments for normal pressure hydrocephalus. Drugs that remove excess fluid throughout the body, such as diuretics, haven't been shown to help.
NPH can sometimes be treated with surgical insertion of a shunt, a long, thin tube that drains excess CSF from the brain to the abdomen. Difficulty walking is the symptom most likely to improve after surgery. Thinking changes and bladder control are less likely to get better. Shunting doesn't help everyone with NPH, and there's uncertainty about how best to identify those most likely to benefit.
More research is needed to:
• Understand the prevalence of NPH
• Show how the excess CSF involved in NPH causes symptoms affecting movement, thinking and bodily functions
• Clarify the possible benefits of shunt insertion and who is most likely to benefit The effectiveness of shunting in NPH has never been demonstrated in a randomized clinical trial. Most of these studies were small and followed people for a limited time. Available data suggest that difficulty walking is the symptom most likely to improve. Several studies found a significant rate of postsurgical complications. Findings also showed that short-term benefits of shunt insertion tended to decline over time.
Huntington's Disease
Huntington’s disease is a progressive brain disorder caused by a single defective gene on chromosome 4.
Symptoms: Include abnormal involuntary movements, a severe decline in thinking and reasoning skills, and irritability, depression and other mood changes.
Brain changes: The gene defect causes abnormalities in a brain protein that, over time, lead to worsening symptoms.
Huntington's disease is a progressive brain disorder caused by a single defective gene on chromosome 4 — one of the 23 human chromosomes that carry a person’s entire genetic code.
This defect is "dominant," meaning that anyone who inherits it from a parent with Huntington's will eventually develop the disease. The disorder is named for George Huntington, the physician who first described it in the late 1800s.
The defective gene codes the blueprint for a protein called huntingtin. This protein's normal function isn't yet known, but it's called "huntingtin" because scientists identified its defective form as the cause of Huntington's disease. Defective huntingtin protein leads to brain changes that cause abnormal involuntary movements, a severe decline in thinking and reasoning skills, and irritability, depression and other mood changes. Symptoms
Symptoms of Huntington's disease usually develop between ages 30 and 50, but they can appear as early as age 2 or as late as 80. The hallmark symptom of Huntington's disease is uncontrolled movement of the arms, legs, head, face and upper body. Huntington's disease also causes a decline in thinking and reasoning skills, including memory, concentration, judgment and ability to plan and organize.
Huntington's disease brain changes lead to alterations in mood, especially depression, anxiety, and uncharacteristic anger and irritability. Another common symptom is
obsessive-compulsive behavior, leading a person to repeat the same question or activity over and over.
Diagnosis
Scientists identified the defective gene that causes Huntington's disease in 1993. A diagnostic genetic test is now available.The test can confirm that the defective gene for huntingtin protein is the cause of symptoms in people with suspected Huntington's disease and can detect the defective gene in people who don't yet have symptoms but are at risk because a parent has Huntington's.
Causes and risks
The defective gene identified in 1993 causes virtually all Huntington’s disease.
The huntingtin gene defect involves extra repeats of one specific chemical code in one small section of chromosome 4. The normal huntingtin gene includes 17 to 20 repetitions of this code among its total of more than 3,100 codes. The defect that causes Huntington's disease includes 40 or more repeats. Genetic tests for Huntington's disease measure the number of repeats present in an individual's
Scientists don't yet understand the normal function of huntingtin protein or how a few dozen extra repeats in its genetic blueprint lead to the devastating symptoms of Huntington's disease. Researchers are eager to solve these mysteries to find the answer to Huntington's. These solutions also may offer important insights into a wide range of other brain disorders, including Alzheimer's, Parkinson's disease and
amyotrophic lateral sclerosis (ALS). Treatment and outcomes
There is currently no cure for Huntington's disease and no way to slow or stop the brain changes it causes. Treatments focus on managing symptoms. A group of international experts recommended the following treatments as first-line strategies for three of the disease's most troubling symptoms:
• Chorea (involuntary movements): Some experts begin treatment with an atypical antipsychotic drug. Others start with another type of drug approved by the U.S. Food and Drug Administration (FDA) specifically for Huntington's.
• Irritability: For severe anger and threatening behavior, experts agree that an atypical antipsychotic drug is the best first-line approach. For less severe, nonthreatening irritability, experts recommend first trying a selective serotonin reuptake inhibitor (SSRI), which is a type of antidepressant.
• Obsessive-compulsive thoughts and actions: Experts also recommended SSRIs as the front-line treatment for obseesive-compulsive behaviors.
Other Huntington's symptoms, such as anxiety, depression and insomnia, also should be treated according to generally accepted guidelines. Experts encourage people with Huntington's to keep all their medical appointments and not to get discouraged if it takes their health care team some time to find the best drugs and the most effective doses.
Wernicke-Korsakoff Syndrome
Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). The most common cause is alcohol misuse.
Symptoms: Memory problems may be strikingly severe while other thinking and social skills seem relatively unaffected.
Brain changes: Thiamine helps brain cells produce energy from sugar. When thiamine levels fall too low, brain cells cannot generate enough energy to function properly.
Thiamine (vitamin B-1) helps brain cells produce energy from sugar. When levels fall too low, brain cells cannot generate enough energy to function properly. As a result, Korsakoff syndrome may develop.
Korsakoff syndrome is most commonly caused by alcohol misuse, but can also be associated with AIDS, chronic infections, poor nutrition and certain other conditions. See causes and risks below.
Korsakoff syndrome is often, but not always, preceded by an episode of Wernicke encephalopathy, which is an acute brain reaction to severe lack of thiamine. Wernicke encephalopathy is a medical emergency that causes life-threatening brain disruption, confusion, staggering and stumbling, lack of coordination, and abnormal involuntary eye movements.
Because the chronic memory loss of Korsakoff syndrome often follows an episode of Wernicke encephalopathy, the chronic disorder is sometimes known as Wernicke-Korsakoff syndrome. But Wernicke-Korsakoff syndrome can also develop in individuals who have not had a prior episode of Wernicke encephalopathy.
Symptoms
Korsakoff syndrome causes problems learning new information, inability to remember recent events and long-term memory gaps. Memory problems may be strikingly severe while other thinking and social skills are relatively unaffected. For example, individuals may seem able to carry on a coherent conversation, but moments later be unable to recall that the conversation took place or to whom they spoke.
Those with Korsakoff syndrome may "confabulate," or make up, information they can't remember. They are not "lying" but may actually believe their invented explanations. Scientists don't yet understand why Korsakoff syndrome may cause confabulation. Diagnosis
Korsakoff syndrome is a clinical diagnosis representing a physician's best judgment about the cause of a person's symptoms. There are no specific lab tests or brain scan procedures to confirm that a person has this disorder. The syndrome may sometimes be hard to identify because it may be masked by symptoms of other conditions common among those who misuse alcohol, including intoxication or withdrawal, infection or head
injury.
Experts recommend that a medical workup for memory loss or other cognitive changes always include questions about an individual's alcohol use. Anyone admitted to the hospital for an alcohol-related condition should be professionally screened for memory loss and cognitive change.
Causes and risks
Scientists don't yet know exactly how Korsakoff syndrome damages the brain. Research has shown that severe thiamine deficiency disrupts several biochemicals that play key roles in carrying signals among brain cells and in storing and retrieving memories. These disruptions destroy brain cells and cause widespread microscopic bleeding and scar tissue.
Most cases of Korsakoff syndrome result from alcohol misuse. Scientists don't yet know why heavy drinking causes severe thiamine deficiency in some alcoholics, while others may be affected primarily by alcohol's effects on the liver, stomach, heart, intestines or other body systems.
Researchers have identified several genetic variations that may increase susceptibility to Korsakoff syndrome. Poor nutrition also may raise risk.
Korsakoff syndrome also can be caused by anorexia, overly-stringent dieting, fasting, starvation or weight-loss surgery; uncontrolled vomiting; AIDS; kidney dialysis; chronic infection; or cancer that has spread throughout the body.
Treatment and outcomes
Some experts recommend that heavy drinkers and others at risk of thiamine deficiency take oral supplements of thiamine and other vitamins under their doctor's supervision. Many experts also recommend that anyone with a history of heavy alcohol use who experiences symptoms associated with Wernicke encephalopathy be given injectable thiamine until the clinical picture grows clearer.
Once acute symptoms improve, individuals should be carefully evaluated to determine if their medical history, alcohol use and pattern of memory problems may be consistent with Korsakoff syndrome. For those who develop Korsakoff syndrome, extended treatment with oral thiamine, other vitamins and magnesium may increase chances of symptom improvement. Giving up alcohol is also an effective treatment.
In those who develop Korsakoff syndrome, with or without a preceding episode of Wernicke encephalopathy, there are few studies on long-term outcomes. Available data suggest that about 25 percent of those who develop Korsakoff syndrome eventually recover, about half improve but don't recover completely, and about 25 percent remain unchanged. Some research suggests that those who recover from an episode may have a normal life expectancy if they abstain from alcohol.
