Dementia is not a specific disease. It is a comprehensive term for various diseases and conditions, identified by a decline in mentality severe enough that it renders a person incapable to perform everyday activities.
Alzheimer's disease accounts for 60 to 80 percent of cases. Vascular dementia, which occurs due to microscopic bleeding and blood vessel blockage in the brain, is the subsequent most common cause of dementia. But there are various other conditions that can cause symptoms of dementia, which include some that are reversible, such as thyroid problems and vitamin deficiencies.
Dementia is often mistakenly referred to as "senility" or "senile dementia," which reflects the formerly extensive but incorrect belief that serious mental decline is a normal part of aging.
Frail Care assistance is required for people struggling with dementia.
While symptoms of dementia can vary greatly, at least some of the following mental functions must be notably impaired to be considered dementia:
- Reasoning and Judgement
- Ability to Pay Attention and Focus
- Communications & Language
- Visual Perception
People with dementia may have trouble with short term memory, planning & preparing meals, paying bills, etc. Many dementias are progressive, meaning symptoms start out slowly and gradually escalate. If you or someone you know is experiencing memory problems or any other changes with thinking skills, don't ignore them. See a doctor as soon as possible to determine the cause. Professional evaluation may detect a treatable condition, early diagnosis allows a person to get the maximum benefit from available treatments.
Dementia is caused by damage to brain cells. Damage to brain cells disrupts the communication between brain cells, which could then affect a person’s thinking, feelings and behaviour.
The brain has various distinct regions, which are all responsible for carrying out different functions (e.g. memory, movement etc.). When cells in one of these regions are damaged, that region can no longer carry out its functions as affectively as it used to, if at all.
Different types of dementia are correlated with particular types of brain cell damage in particular regions. For example, in Alzheimer's disease, high levels of certain proteins inside and outside brain cells make it hard for brain cells to stay healthy and communicative with each other.
The brain cells in the hippocampus (the center of learning and memory) region are often the first to be damaged. That's why memory loss is frequently one of the earliest symptoms of Alzheimer's. While most changes in the brain that cause dementia are permanent, mentality problems caused by the following conditions may improve once the condition is treated or addressed:
- Thyroid Problems
- Vitamin Deficiencies
- Excess Use of Alcohol
- Medication Side Effects
There is no one test to determine if someone has dementia. Doctors diagnose Alzheimer's and other types of dementia based on a careful medical history, a physical examination, laboratory tests, and the characteristic changes in mentality, day-to-day function and behaviour associated with each type.
Doctors can determine that a person has dementia with a high level of certainty. But it's harder to determine the exact type of dementia because the symptoms and brain changes of different dementias can overlap. In some cases, a doctor may diagnose "dementia" and not specify a type. If this occurs it may be necessary to see a specialist such as a neurologist or gero-psychologist.
Alzheimer's disease is a progressive disorder that causes brain cells to waste away (degenerate) and die. Alzheimer's disease is the most common cause of dementia — a continuous decline in thinking, behavioural and social skills that disrupts a person's ability to function independently.
The early signs of the disease may be forgetting recent events or conversations, but as the disease progresses, the person will develop severe memory impairment and lose the ability to carry out everyday tasks.
Current Medications may temporarily improve symptoms or slow the rate of decline. These treatments can sometimes help the person maximize function and maintain independence for a little bit more time.
There is no treatment that cures or alters the disease process in the brain. In advanced stages of the disease, complications from severe loss of brain function, such as dehydration, malnutrition or infection, result in death.
Memory loss is the key symptom of Alzheimer's disease.Brain changes associated with Alzheimer's disease lead to growing trouble with:
- Repeat statements and questions over and over
- Forget conversations, appointments or events, and not remember them later
- Routinely misplace possessions, often putting them in illogical locations
- Get lost in familiar places
- Eventually forget the names of family members and everyday objects
- Have trouble finding the right words to identify objects, express thoughts or take part in conversations
- Thinking and Reasoning
- Making Judgements and Decisions
- Planning and Performing Familiar Tasks
Changes in Personality and Behaviour -
- Social withdrawal
- Mood swings
- Distrust in others
- Irritability and aggressiveness
- Changes in sleeping habits
- Loss of inhibitions
- Delusions, such as believing something has been stolen
- Preserved skills - Preserved skills may include reading or listening to books, telling stories, singing, listening to music, dancing, drawing, or doing crafts. These skills may be preserved longer because they are controlled by parts of the brain affected later in the course of the disease.
Scientists believe that for most people, the disease is caused by a combination of genetic, lifestyle and environmental factors that affect the brain over time. Less than 1 percent of the time, the disease is caused by specific genetic changes that virtually guarantee a person will develop the disease. These rare occurrences usually result in disease onset in middle age.
The exact causes are not fully understood, but at its core are problems with brain proteins that fail to function normally, thus disrupting the work of brain cells (neurons) and unleashes a series of toxic events. Neurons are damaged which then causes them lose connection to each other and eventually die.
The damage most often starts in the region of the brain that controls memory, but the process begins years before the first symptoms. The loss of neurons spreads in a somewhat predictable pattern to other regions of the brain. By the late stage of the disease, the brain has already shrunken significantly.
Researchers are focused on the role of two proteins:
Plaques: Beta-amyloid is a leftover fragment of a larger protein. When these fragments cluster together, they appear to have a toxic effect on neurons and disrupt cell-to-cell communication. These clusters form larger deposits called amyloid plaques, which also include other cellular debris.
Tangles: Tau proteins play a part in a neuron's internal support and transport system to carry nutrients and other essential materials. In Alzheimer's disease, tau proteins change shape and organize themselves into structures called neurofibrillary tangles. The tangles disrupt the transport system and are toxic to cells.
Age - Increasing age is the greatest known risk factor for Alzheimer's disease even though it is not part of normal aging, but as you grow older the likelihood of developing Alzheimer's disease increases.
Family History and Genetics - Your risk of developing Alzheimer's is somewhat higher if a first-degree relative, your parent or sibling, has the disease. Most genetic mechanisms of Alzheimer's among families remain largely unexplained, and the genetic factors are likely complex.
Down syndrome - Many people with Down syndrome develop Alzheimer's disease. This is likely related to having three copies of chromosome 21, and subsequently three copies of the gene for the protein that leads to the creation of beta-amyloid. Signs and symptoms of Alzheimer's tend to appear 10 to 20 years earlier in people with Down syndrome than they do for the general population.
Sex - There appears to be little difference in risk between men and women, but overall, there are more women with the disease because they generally live longer than men.
Mild Cognitive Impairment - Mild cognitive impairment (MCI) is a decline in memory or other thinking skills that is greater than what would be expected for a person's age, but the decline doesn't prevent a person from functioning in social or work environments.
Past Head Trauma - People who've had a severe head trauma have a greater risk of Alzheimer's disease.
Poor Sleep Patterns - Research has shown that poor sleep patterns, such as difficulty falling asleep or staying asleep, are associated with an increased risk of Alzheimer's disease.Lifestyle and Heart Health - Research has shown that the same risk factors associated with heart disease may also increase the risk of Alzheimer's disease. These include:
- Lack of exercise
- Smoking or exposure to secondhand smoke
- High blood pressure
- High cholesterol
- Poorly controlled type 2 diabetes
Vascular dementia is an overall term used to describe problems with reasoning, planning, judgment, memory and other thought processes caused by damage to the brain, due to impaired blood flow to your brain.
You can develop vascular dementia after a stroke blocks an artery in your brain, but strokes don't always cause vascular dementia. Whether a stroke affects your thinking and reasoning can be determined on your stroke's severity and location. Vascular dementia can also be a result of other conditions that damage blood vessels and reduce circulation, depriving your brain of vital oxygen and nutrients.
The risk of vascular dementia can also be raised by factors that increases the risk of heart disease or strokes such as diabetes, high blood pressure, high cholesterol and smoking. Controlling these factors may help lower the risk of developing vascular dementia.
Vascular dementia symptoms vary, depending on the part of your brain where blood flow is impaired. Symptoms often overlap with those of other types of dementia, especially those of Alzheimer's disease.Vascular dementia signs and symptoms include:
- Trouble paying attention and concentrating
- Reduced ability to organize thoughts or actions
- Decline in ability to analyse a situation, develop an effective plan and communicate that plan to others
- Difficulty deciding what to do next
- Problems with memory
- Restlessness and agitation
- Unsteady gait
- Sudden or frequent urge to urinate or inability to control passing urine
- Depression or Apathy
Vascular dementia symptoms may be most clear-cut when they occur suddenly following a stroke. When changes in your thinking and reasoning seem clearly linked to a stroke, this condition is sometimes called post-stroke dementia. Changes in your thought processes occur in noticeable steps downward from your previous level of function, unlike the gradual, steady decline that typically occurs in Alzheimer's disease. But vascular dementia can also develop very gradually, just like Alzheimer's disease. What's more, vascular disease and Alzheimer's disease often occur together.
Vascular dementia results from damage to your brain's blood vessels, reducing their ability to supply your brain with the amounts of nutrition and oxygen it needs to perform thought processes effectively.Common conditions that may lead to vascular dementia include:
- Stroke - (infarction) blocking a brain artery. Strokes that block a brain artery usually cause a range of symptoms that may include vascular dementia. But some strokes don't cause any noticeable symptoms. These silent strokes still increase dementia risk. With both silent and apparent strokes, the risk of vascular dementia increases with the number of strokes that occur over time. One type of vascular dementia involving many strokes is called multi-infarct dementia.
- Narrowed or chronically damaged brain blood vessels - Conditions that narrow or inflict long-term damage on your brain blood vessels also can lead to vascular dementia. These conditions include the wear and tear associated with aging, high blood pressure, abnormal aging of blood vessels (atherosclerosis), diabetes, and brain haemorrhage.
The risk factors for vascular dementia are in general, the same as those for heartdisease and stroke. Risk factors for vascular dementia include:
- Increasing age - Your risk of vascular dementia rises as you grow older. The disorder is rare before age 65, and the risk rises substantially by your 90s. History of heart attack, strokes or ministrokes, If you've had a heart attack, you may be at increased risk of having blood vessel problems in your brain. The brain damage that occurs with a stroke or a ministroke (transient ischemic attack) may increase your risk of developing dementia.
- Abnormal aging of blood vessels (atherosclerosis) - This condition occurs when deposits of cholesterol and other substances (plaques) build up in your arteries and narrow your blood vessels. Atherosclerosis can increase your risk of vascular dementia by reducing the flow of blood that nourishes your brain.
- High cholesterol - Elevated levels of low-density lipoprotein (LDL), the "bad" cholesterol, are associated with an increased risk of vascular dementia.
- High blood pressure - When your blood pressure's too high, it puts more stress on blood vessels everywhere in your body, including your brain. This increases the risk of vascular problems in the brain.
- Diabetes - High glucose levels damage blood vessels throughout your body. Damage in brain blood vessels can increase your risk of stroke and vascular dementia.
- Smoking - Smoking directly damages your blood vessels, increasing your risk of atherosclerosis and other circulatory diseases, including vascular dementia.
- Obesity - Being overweight is a well-known risk factor for vascular diseases in general, and therefore, presumably increases your risk of vascular dementia.
- Atrial fibrillation - In this abnormal heart rhythm, the upper chambers of your heart begin to beat rapidly and irregularly, out of coordination with your heart's lower chambers. Atrial fibrillation increases your risk of stroke because it causes blood clots to form in the heart that can break off and go to the brain blood vessels.
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 ministroke or have high blood pressure, high cholesterol, or other risk factors for heart or blood vessel disease.
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:
- The diagnosis of dementia or mild cognitive impairment is confirmed by neurocognitive testing, which involves several hours of written or computerized tests that provide detailed evaluation of specific thinking skills such as judgment, planning, problem-solving, reasoning and memory.
- 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.
- 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.
Dementia with Lewy Bodies
Lewy body dementia, also known as dementia with Lewy bodies, is the second most common type of progressive dementia after Alzheimer's. Protein deposits, called Lewy bodies, develop in nerve cells in the brain regions involved in thinking, memory and movement (motor control).
Lewy body dementia causes a progressive decline in mental abilities. People with Lewy body dementia may experience visual hallucinations and changes in alertness and attention. Other effects include Parkinson's disease-like signs and symptoms such as rigid muscles, slow movement and tremors.
Lewy body dementia signs and symptoms may include:
- Visual Hallucinations - Hallucinations may be one of the first symptoms, and they often recur. They may include seeing shapes, animals or people that aren't there. Sound (auditory), smell (olfactory) or touch (tactile) hallucinations are possible. Movement disorders - Signs of Parkinson's disease (parkinsonian signs), such as slowed movement, rigid muscles, tremor or a shuffling walk may occur. This can also result in falls.
- Poor regulation of body functions (autonomic nervous system) - Blood pressure, pulse, sweating and the digestive process are regulated by a part of the nervous system that is often affected by Lewy body dementia. This can result in dizziness, falls and bowel issues such as constipation.
- Cognitive problems - You may experience thinking (cognitive) problems similar to those of Alzheimer's disease, such as confusion, poor attention, visual-spatial problems and memory loss.
- Sleep difficulties - You may have rapid eye movement (REM) sleep behaviour disorder, which can cause you to physically act out your dreams while you're asleep.
- Fluctuating attention - Episodes of drowsiness, long periods of staring into space, long naps during the day or disorganized speech are possible.
- Depression - You may experience depression sometime during the course of your illness.
- Apathy - You may have loss of motivation.
Lewy body dementia is characterized by the abnormal build-up of proteins into masses known as Lewy bodies. This protein is also associated with Parkinson's disease.
People who have Lewy bodies in their brains also have the plaques and tangles associated with Alzheimer's disease.
A few factors seem to increase the risk of developing Lewy body dementia, including:
- Age - People older than 60 are at greater risk.
- Sex - Lewy body dementia affects more men than women.
- Family history - Those who have a family member with Lewy body dementia or Parkinson's disease are at greater risk.
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 post-mortem 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:
- Dementia symptoms consistent with DLB develop first
- When both dementia symptoms and movement symptoms are present at the time of diagnosis
- When dementia symptoms appear within one year after movement symptoms.
There are no treatments that can slow or stop the brain cell damage caused by dementia with Lewy bodies. Current strategies focus on helping symptoms.
If your treatment plan includes medication, 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 inhibiltors drugs are the current mainstay for treating thinking changes in Alzheimer's. They also may help certain DLB symptoms.
Antipsychotic drugs should be used with extreme caution in DLB. Although physicians sometimes prescribe these drugs for behavioural symptoms that can occur in Alzheimer's, they may cause serious side effects in as many as 50 percent of those with DLB. 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.
Antidepressants may be used to treat depression, which is common with DLB, Parkinson's disease dementia and Alzheimer's.The most commonly used antidepressants are selective serotonin reuptake inhibitors (SSRIs).
Clonazepam may be prescribed to treat REM sleep disorder.
Parkinson's disease is a progressive nervous system disorder that affects movement. Symptoms start gradually, sometimes starting with a barely noticeable tremor in just one hand. Tremors are common, but the disorder also commonly causes stiffness or slowing of movement.
In the early stages of Parkinson's disease, your face may show little or no expression. Your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time.
Although Parkinson's disease can't be cured, medications might significantly improve your symptoms. Occasionally, your doctor may suggest surgery to regulate certain regions of your brain and improve your symptoms.
Parkinson's disease signs and symptoms can be different for everyone. Early signs may be mild and go unnoticed. Symptoms often begin on one side of your body and usually remain worse on that side, even after symptoms begin to affect both sides. Parkinson's signs and symptoms may include:
- Tremor - A tremor, or shaking, usually begins in a limb, often your hand or fingers. You may a rub your thumb and forefinger back-and- forth, known as a pill-rolling tremor. Your hand may tremor when it's at rest.
- Slowed movement (bradykinesia) - Over time, Parkinson's disease may slow your movement, making simple tasks difficult and time consuming. Your steps may become shorter when you walk. It may be difficult to get out of a chair. You may drag your feet as you try to walk.
- Rigid muscles - Muscle stiffness may occur in any part of your body. The stiff muscles can be painful and limit your range of motion.
- Impaired posture and balance - Your posture may become stooped, or you may have balance problems as a result of Parkinson's disease.
- Loss of automatic movements - You may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk.
- Speech changes - You may speak softly, quickly, slur or hesitate before talking. Your speech may be more of a monotone rather than with the usual inflections.
- Writing changes - It may become hard to write, and your writing may appear small.
In Parkinson's disease, certain nerve cells (neurons) in the brain gradually break down or die. Many of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes abnormal brain activity, leading to symptoms of Parkinson's disease. The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:
- Your genes - Researchers have identified specific genetic mutations that can cause Parkinson's disease. But these are uncommon except in rare cases with many family members affected by Parkinson's disease. However, certain gene variations appear to increase the risk of Parkinson's disease but with a relatively small risk of Parkinson's disease for each of these genetic markers.
Environmental triggers - Exposure to certain toxins or environmental factors may
increase the risk of later Parkinson's disease, but the risk is relatively
Researchers have also noted that many changes occur in the brains of people with
Parkinson's disease, although it's not clear why these changes occur. These
- The presence of Lewy bodies - Clumps of specific substances within brain cells are microscopic markers of Parkinson's disease. These are called Lewy bodies, and researchers believe these Lewy bodies hold an important clue to the cause of Parkinson's disease.
- Alpha-synuclein is found within Lewy bodies - Although many substances are found within Lewy bodies, scientists believe an important one is the natural and widespread protein called alpha-synuclein (a-synuclein). It's found in all Lewy bodies in a clumped form that cells can't break down. This is currently an important focus among Parkinson's disease researchers.
Risk factors for Parkinson's disease include:
- Age - Young adults rarely experience Parkinson's disease. It ordinarily begins in middle or late life, and the risk increases with age. People usually develop the disease around age 60 or older.
- Heredity - Having a close relative with Parkinson's disease increases the chances that you'll develop the disease. However, your risks are still small unless you have many relatives in your family with Parkinson's disease.
- Sex - Men are more likely to develop Parkinson's disease than women.
- Exposure to toxins - Ongoing exposure to herbicides and pesticides may slightly increase your risk of Parkinson's disease.
There is no single test to conclusively diagnose Parkinson’s disease (PD). However, there are various symptoms and diagnostic tests used in combination. Making an accurate diagnosis of Parkinson’s, particularly in its early stages, is difficult, but a skilled practitioner can come to a reasoned conclusion that it is PD. It is important to remember that two of the four main symptoms must be present over a period of time for a neurologist to consider a PD diagnosis:
- Shaking or tremor
- Slowness of movement, called bradykinesia
- Stiffness or rigidity of the arms, legs or trunk
- Trouble with balance and possible falls, also called postural instability
Often, a Parkinson’s diagnosis is first made by an internist or family physician. Many people seek an additional opinion from a neurologist with experience and specific training in the assessment and treatment of PD - referred to as a movement disorder specialist.
Frontotemporal dementia is an umbrella term for a group of uncommon brain disorders that primarily affect the frontal and temporal lobes of the brain. These areas of the brain are generally associated with personality, behavior and language.
In frontotemporal dementia, portions of these lobes shrink (atrophy). Signs and symptoms vary, depending on which part of the brain is affected. Some people with frontotemporal dementia have dramatic changes in their personality and become socially inappropriate, impulsive or emotionally indifferent, while others lose the ability to use language properly.
Frontotemporal dementia is often misdiagnosed as a psychiatric problem or as Alzheimer's disease. But frontotemporal dementia tends to occur at a younger age than Alzheimer's. Frontotemporal dementia often begins between the ages of 40 and 65.
Signs and symptoms of frontotemporal dementia can be different from one individual to the next. Signs and symptoms get progressively worse over time, usually over years. Clusters of symptom types tend to occur together, and people may have more than one cluster of symptom types, which include:
Behavioural changes - Increasingly inappropriate social behaviour such as:
- Loss of empathy and other interpersonal skills, such as having sensitivity to another's feelings
- Lack of judgment
- Loss of inhibition
- Lack of interest (apathy), which can be mistaken for depression
- Repetitive compulsive behaviour, such as tapping, clapping or smacking lips
- A decline in personal hygiene
- Changes in eating habits, usually overeating or developing a preference for sweets and carbohydrates
- Eating inedible objects
- Compulsively wanting to put things in the mouth
Speech and language problems –
Some subtypes of frontotemporal dementia lead to language problems or impairment
loss of speech. Primary Progressive Aphasia (PPA), semantic dementia and
agrammatic (non-fluent) aphasia are all considered to be frontotemporal
- Increasing difficulty in using and understanding written and spoken language, such as having trouble finding the right word to use in speech or naming objects
- Trouble naming things, possibly replacing a specific word with a more general word such as "it" for pen
- No longer knowing word meanings
- Having hesitant speech that may sound telegraphic
- Making mistakes in sentence construction
Movement disorders –
Rarer subtypes of frontotemporal dementia are characterized by problems with
movement, similar to those associated with Parkinson's disease or amyotrophic
lateral sclerosis (ALS). Movement-related problems may include:
- Muscle spasms
- Poor coordination
- Difficulty swallowing
- Muscle weakness
- Inappropriate laughing or crying
In frontotemporal dementia, the frontal and temporal lobes of the brain shrink. In addition, certain substances accumulate in the brain. What causes these changes is usually unknown.
There are genetic mutations that have been linked to frontotemporal dementia. But more than half of the people who develop frontotemporal dementia have no family history of dementia.
Recently, researchers have confirmed shared genetics and molecular pathways between frontotemporal dementia and amyotrophic lateral sclerosis (ALS). More research needs to be done to understand the connection between these conditions, however.
Creutzfeldt-Jakob (KROITS-felt YAH-kobe) disease is a degenerative brain disorder that leads to dementia and, ultimately, death. Symptoms of Creutzfeldt-Jakob disease (CJD) can resemble those of other dementia like brain disorders, such as Alzheimer's. But Creutzfeldt-Jakob disease usually progresses much more rapidly.
CJD captured public attention in the 1990s when some people in the United Kingdom developed a form of the disease, variant CJD (vCJD), after eating meat from diseased cattle. However, "classic" Creutzfeldt-Jakob disease hasn't been linked to contaminated beef.
Although serious, CJD is rare, and vCJD is the least common form. Worldwide, there is an estimated one case of CJD diagnosed per million people each year, most often in older adults.
Creutzfeldt-Jakob disease is marked by rapid mental deterioration, usually within a few months. Initial signs and symptoms typically include:
- Personality changes
- Memory loss
- Impaired thinking
- Blurred vision or blindness
- Difficulty speaking
- Difficulty swallowing
- Sudden, jerky movements
As the disease progresses, mental symptoms worsen. Most people eventually lapse into a coma. Heart failure, respiratory failure, pneumonia or other infections are generally the cause of death. Death usually occurs within a year.
In people with the rarer vCJD, psychiatric symptoms may be more prominent in the beginning, with dementia, the loss of the ability to think, reason and remember, developing later in the illness. In addition, this variant affects people at a younger age than classic CJD does and appears to have a slightly longer duration of 12 to 14 months.
Creutzfeldt-Jakob disease and its variants belong to a broad group of human and animal diseases known as transmissible spongiform encephalopathies (TSEs). The name derives from the spongy holes, visible under a microscope, that develop in affected brain tissue.
The cause of Creutzfeldt-Jakob disease and other TSEs appears to be abnormal versions of a kind of protein called a prion. Normally these proteins are harmless. But when they're misshapen, they become infectious and can harm normal biological processes.
The risk of CJD is low. The disease can't be transmitted through coughing or sneezing, touching, or sexual contact. The three ways it develops are:
- Sporadically - Most people with classic CJD develop the disease for no apparent reason. Termed spontaneous CJD or sporadic CJD, this type accounts for the majority of cases.
- By inheritance - Fewer than 15 percent of people with CJD have afamily history of the disease or test positive for a genetic mutation associated with CJD. This type is referred to as familial CJD.
- By contamination - A small number of people have developed CJD after being exposed to infected human tissue during a medical procedure, such as a cornea or skin transplant. Also, because standard sterilization methods do not destroy abnormal prions, a few people have developed CJD after undergoing brain surgery with contaminated instruments.
Cases of CJD related to medical procedures are referred to as iatrogenic CJD. Variant CJD is linked primarily to eating beef infected with mad cow disease (bovine spongiform encephalopathy, or BSE).
Most cases of Creutzfeldt-Jakob disease occur for unknown reasons, and no risk factors can be identified. However, a few factors seem to be associated with different kinds of CJD.
- Age - Sporadic CJD tends to develop later in life, usually around age 60. Onset of familial CJD occurs slightly earlier and vCJD has affected people at a much younger age, usually in their late 20s.
- Genetics - People with familial CJD have a genetic mutation that causes the disease. The disease is inherited in an autosomal dominant fashion, which means you need to inherit only one copy of the mutated gene, from either parent, to develop the disease. If you have the mutation, the chance of passing it on to your children is 50 percent.
Genetic analysis in people with iatrogenic and vCJD suggest that inheriting identical copies of certain variants of the prion gene may increase your risk of developing CJD if you're exposed to contaminated tissue.
Exposure to contaminated tissue - People who've received human growth hormone derived from human pituitary glands or who've had grafts of tissue that covers the brain (dura mater) may be at risk of iatrogenic CJD.
The risk of contracting vCJD from eating contaminated beef is difficult to determine. In general, if countries are effectively implementing public health measures, the risk is virtually non-existent.
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.
Normal Pressure Hydrocephalus
Normal pressure hydrocephalus is a brain disorder in which excess cerebrospinal fluid accumulates in the brain’s ventricles, which are fluid-filled chambers. NPH is called "normal pressure" because despite the excess fluid, CSF pressure as measured during a spinal tap is often normal. As brain ventricles enlarge with the excess CSF, they can disrupt and damage nearby brain tissue, leading to difficulty walking, problems with thinking and reasoning, and loss of bladder control.
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. Surgery is most likely to help correct difficulties walking, but thinking changes and loss of bladder control are less likely to improve. Shunting doesn’t help everyone with normal pressure hydrocephalus, and there’s uncertainty about how best to identify those most likely to benefit. There’s also a lack of data showing how long the benefit of shunting may last for those whose symptoms improve.
The following symptoms are considered hallmarks of NPH:
- 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."
- Mild dementia that involves loss of interest in daily activities, forgetfulness, difficulty completing routine tasks and short-term memory loss.
- Decline in thinking skills that includes overall slowing of thought processes, apathy, impaired planning and decision-making, reduced concentration, and changes in personality and behaviour.
- Loss of bladder control, which tends to appear somewhat later in the disease than difficulty walking and cognitive decline.
In some cases, NPH is caused by other brain disorders such as a tumor, head injury, haemorrhage, infection or inflammation. But in most cases, the cause of the fluid build-up remains unknown.
There is no single test to determine if someone has NPH. And even though the 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.
Huntington's disease is a inherited 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 after 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.
Huntington's disease usually causes movement, cognitive and psychiatric disorders with a wide spectrum of signs and symptoms. Which symptoms appear first varies greatly among affected people. During the course of the disease, some disorders appear to be more dominant or have a greater effect on functional ability.
Movement disorders –
The movement disorders associated with Huntington's disease can include both
involuntary movement problems and impairments in voluntary movements, such as:
- Involuntary jerking or writhing movements (chorea)
- Muscle problems, such as rigidity or muscle contracture (dystonia)
- Slow or abnormal eye movements
- Impaired gait, posture and balance
- Difficulty with the physical production of speech or swallowing
Cognitive disorders -
Cognitive impairments often associated with Huntington's disease include:
- Difficulty organizing, prioritizing or focusing on tasks
- Lack of flexibility or the tendency to get stuck on a thought, behaviour or action (perseveration)
- Lack of impulse control that can result in outbursts, acting without thinking and sexual promiscuity
- Lack of awareness of one's own behaviours and abilities
- Slowness in processing thoughts or ''finding'' words
- Difficulty in learning new information
Psychiatric disorders -
The most common psychiatric disorder associated with Huntington's disease is
depression. Depression appears to occur because of injury to the brain and
subsequent changes in brain function. Signs and symptoms may include:
- Feelings of irritability, sadness or apathy
- Social withdrawal
- Fatigue and loss of energy
- Frequent thoughts of death, dying or suicide
- Obsessive-compulsive disorder - a condition marked by recurrent, intrusive thoughts and repetitive behaviours
- Mania - which can cause elevated mood, overactivity, impulsive behaviour and inflated self-esteem
- Bipolar disorder - a condition with alternating episodes of depression and mania
Symptoms of juvenile Huntington's disease The start and progression of Huntington's disease in younger people may be slightly different from that in adults. Problems that often present themselves early in the course of the disease include:
- Behavioural changes
- Loss of previously learned academic or physical skills
- Rapid, significant drop in overall school performance
- Behavioural problems
- Physical changes
- Contracted and rigid muscles that affect gait (especially in young children)
- Changes in fine motor skills that might be noticeable in skills such as handwriting
- Tremors or slight involuntary movements
Huntington's disease is caused by an inherited defect in a single gene. Huntington's disease is an autosomal dominant disorder, which means that a person needs only one copy of the defective gene to develop the disorder.
With the exception of genes on the sex chromosomes, a person inherits two copies of every gene - one copy from each parent. A parent with a defective gene could pass along the defective copy of the gene or the healthy copy. Each child in the family, therefore, has a 50 percent chance of inheriting the gene that causes the genetic disorder.
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.
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 believe beginning treatment with an atypical antipsychotic drug, such as olanzapine, is best. Others start with another type of drug recently approved by the U.S. Food and Drug Administration (FDA) specifically for Huntington’s, called tetrabenazine.
- Irritability: For severe anger and threatening behaviour, experts agree that an atypical antipsychotic drug is the preferred 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 recommend SSRIs as the standard treatment for these symptoms.
Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). Korsakoff syndrome is most commonly caused by alcohol misuse, but certain other conditions also can cause the syndrome.
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 mostly 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 Korsakoff syndrome can also develop in individuals who have not had a prior episode of Wernicke encephalopathy. We recommend frail care assistance to people who suffer from this ailment.
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.
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. Sign up for our enews to receive updates about Alzheimer’s and dementia care and research. 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.
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.
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.