Cholinergic Neurotransmission And Alzheimer Disease
The cholinergic system is involved in memory function, and cholinergic deficiency has been implicated in the cognitive decline and behavioral changes of AD. Activity of the synthetic enzyme choline acetyltransferase and the catabolic enzyme acetylcholinesterase are significantly reduced in the cerebral cortex, hippocampus, and amygdala in patients with AD.
The nucleus basalis of Meynert and diagonal band of Broca provide the main cholinergic input to the hippocampus, amygdala, and neocortex, which are lost in patients with AD. Loss of cortical CAT and decline in acetylcholine synthesis in biopsy specimens have been found to correlate with cognitive impairment and reaction-time performance. Because cholinergic dysfunction may contribute to the symptoms of patients with AD, enhancing cholinergic neurotransmission constitutes a rational basis for symptomatic treatment.
Signs And Symptoms Of Alzheimer’s Disease
Alzheimer’s disease is a progressive condition, which means the symptoms develop gradually over many years and eventually become more severe. It affects multiple brain functions.
The first sign of Alzheimer’s disease is usually minor memory problems.
For example, this could be forgetting about recent conversations or events, and forgetting the names of places and objects.
As the condition develops, memory problems become more severe and further symptoms can develop, such as:
- confusion, disorientation and getting lost in familiar places
- difficulty planning or making decisions
- problems with speech and language
- problems moving around without assistance or performing self-care tasks
- personality changes, such as becoming aggressive, demanding and suspicious of others
- hallucinations and delusions
- low mood or anxiety
Read more about the symptoms of Alzheimer’s disease.
What Are The Warning Signs Of Alzheimers Disease
Watch this video Memory Loss is Not a Normal Part of Aging
Alzheimers disease is not a normal part of aging. Memory problems are typically one of the first warning signs of Alzheimers disease and related dementias.
In addition to memory problems, someone with symptoms of Alzheimers disease may experience one or more of the following:
- Memory loss that disrupts daily life, such as getting lost in a familiar place or repeating questions.
- Trouble handling money and paying bills.
- Difficulty completing familiar tasks at home, at work or at leisure.
- Misplacing things and being unable to retrace steps to find them.
- Changes in mood, personality, or behavior.
Even if you or someone you know has several or even most of these signs, it doesnt mean its Alzheimers disease. Know the 10 warning signs .
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What Is Alzheimers Disease
Alzheimers disease is the most common type of irreversible dementia . Nearly 7 out of 10 people with dementia have the Alzheimers type.
While Alzheimers disease affects up to 1 in 10 Australians over 65 years of age, and up to 3 in 10 Australians over 85, it is not a normal part of ageing.
The brain contains millions of brain cells that organise how the brain stores memories, learns habits and shapes our personality. Signals pass along the connections between brain cells in the form of chemicals called neurotransmitters. Alzheimers disease affects these cells and chemicals, disturbing memory, impairing thinking and causing behaviour changes over time. People with Alzheimers disease eventually need long-term care and support.
There are 2 main types of Alzheimers disease:
- Sporadic Alzheimers is the most common form and usually occurs after age 65. Its cause is not fully understood.
- Familial Alzheimers is caused by a very rare genetic condition and results in dementia, usually in people in their 40s and 50s. This is known as younger onset dementia.
Symptoms Of Mild Dementia Due To Alzheimers
- Memory lapses that impact the ability to complete normal daily tasks
- Losing things or leaving them in odd places
- Wandering or becoming lost in familiar places
- Poor judgment, personality changes, increased anxiety or aggression
- Repeatedly asking the same question or questions
- Problems with life tasks like paying bills, buying groceries, reaching appointments
- Difficulty finding the right words to describe things or express emotions
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Mild Impairment Or Decline
The symptoms of Alzheimers are less clear during stage 3. While the entire stage lasts about 7 years, the symptoms will slowly become clearer over a period of 2 to 4 years. Only people close to someone in this stage may notice the symptoms. Work quality will decline, and they may have trouble learning new skills.
Other examples of stage 3 symptoms and signs include:
- getting lost even when traveling a familiar route
- finding it hard to remember the right words or names
- being unable to remember what you just read
- not remembering new names or people
- misplacing or losing a valuable object
A doctor or clinician may also have to conduct a more intense interview than usual to discover cases of memory loss.
Caregiver support: At this stage, someone with Alzheimers may need counseling, especially if they have complex job responsibilities. They may experience mild to moderate anxiety and denial.
Support For Family And Friends
Currently, many people living with Alzheimers disease are cared for at home by family members. Caregiving can have positive aspects for the caregiver as well as the person being cared for. It may bring personal fulfillment to the caregiver, such as satisfaction from helping a family member or friend, and lead to the development of new skills and improved family relationships.
Although most people willingly provide care to their loved ones and friends, caring for a person with Alzheimers disease at home can be a difficult task and may become overwhelming at times. Each day brings new challenges as the caregiver copes with changing levels of ability and new patterns of behavior. As the disease gets worse, people living with Alzheimers disease often need more intensive care.
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Psychological And Psychosocial Therapies
Psychological therapies for dementia include some limited evidence for reminiscence therapy , some benefit for cognitive reframing for caretakers, unclear evidence for validation therapy and tentative evidence for mental exercises, such as cognitive stimulation programs for people with mild to moderate dementia. Offering personally tailored activities may help reduce challenging behavior and may improve quality of life. It is not clear if personally tailored activities have an impact on affect or improve for the quality of life for the caregiver.
Adult daycare centers as well as special care units in nursing homes often provide specialized care for dementia patients. Daycare centers offer supervision, recreation, meals, and limited health care to participants, as well as providing respite for caregivers. In addition, home care can provide one-to-one support and care in the home allowing for more individualized attention that is needed as the disorder progresses. Psychiatric nurses can make a distinctive contribution to people’s mental health.
Some London hospitals found that using color, designs, pictures and lights helped people with dementia adjust to being at the hospital. These adjustments to the layout of the dementia wings at these hospitals helped patients by preventing confusion.
Personally tailored activities
Stage : Very Mild Changes
You still might not notice anything amiss in your loved one’s behavior, but they may be picking up on small differences, things that even a doctor doesn’t catch. This could include forgetting words or misplacing objects.
At this stage, subtle symptoms of Alzheimer’s don’t interfere with their ability to work or live independently.
Keep in mind that these symptoms might not be Alzheimer’s at all, but simply normal changes from aging.
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Caring For Someone With Alzheimers Disease
Caring for someone with Alzheimers disease can be hard but also rewarding. Your emotional and physical support will be a great help when the person’s world seems confusing and hostile. Take advantage of the community support thats available for people with Alzheimers disease, their families and carers.
Preclinical Alzheimers Or No Impairment
You may only know about your risk of Alzheimers disease due to your family history. Or a doctor may identify biomarkers that indicate your risk.
If youre at risk of Alzheimers, a doctor will interview you about memory difficulties. However, there will be no noticeable symptoms during the first stage, which can last for years or decades.
Abnormal accumulation of a type of protein called tau in the fluid around your brain and spinal cord is associated with the development of Alzheimers disease. Changes in the levels of this protein can occur about 15 years before symptoms start.
Caregiver support: Someone in this stage is fully independent. They may not even know they have the disease.
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Oxidative Stress And Damage
Oxidative damage occurs in AD. Studies have demonstrated that an increase in oxidative damage selectively occurs within the brain regions involved in regulating cognitive performance.
Oxidative damage potentially serves as an early event that then initiates the development of cognitive disturbances and pathological features observed in AD. A decline in protein synthesis capabilities occurs in the same brain regions that exhibit increased levels of oxidative damage in patients with mild cognitive impairment and AD. Protein synthesis may be one of the earliest cellular processes disrupted by oxidative damage in AD.
Oxidative stress is believed to be a critical factor in normal aging and in neurodegenerative diseases such as Parkinson disease, amyotrophic lateral sclerosis, and AD. Formation of free carbonyls and thiobarbituric acid-reactive products, an index of oxidative damage, are significantly increased in AD brain tissue compared with age-matched controls. Plaques and tangles display immunoreactivity to antioxidant enzymes.
Multiple mechanisms exist by which cellular alterations may be induced by oxidative stress, including production of reactive oxygen species in the cell membrane . This in turn impairs the various membrane proteins involved in ion homeostasis such as N -methyl-D-aspartate receptor channels or ion-motive adenosine triphosphatases.
What Are Some Complications Of Alzheimers Disease
Alzheimers disease is an irreversible form of dementia. The rate of progression differs between people: some people have it only in the last 5 years of their life, while others may have it for as long as 20 years. Alzheimers disease eventually leads to complete dependence and increasing frailty. This means a secondary illness, such as pneumonia, may eventually cause death.
Other complications of Alzheimers disease may include:
- an inability to complete daily tasks such as planning meals and managing money
- a tendency to wander from home
- personality changes such as anxiety, depression and irritability that make relationships more difficult
- delusions and hallucinations in advanced stages of the disease
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Signs Of Moderate Alzheimers Disease
In this stage, more intensive supervision and care become necessary, which can be difficult for many spouses and families. Symptoms may include:
- Increased memory loss and confusion
- Inability to learn new things
- Difficulty with language and problems with reading, writing, working with numbers
- Difficulty organizing thoughts and thinking logically
- Shortened attention span
- Problems coping with new situations
- Difficulty carrying out multistep tasks, such as getting dressed
- Problems recognizing family and friends
- Hallucinations, delusions, and paranoia
- Impulsive behavior such as undressing at inappropriate times or places or using vulgar language
- Inappropriate outbursts of anger
- Restlessness, agitation, anxiety, tearfulness, wanderingespecially in the late afternoon or evening
- Repetitive statements or movement, occasional muscle twitches
Who Gets Alzheimers Disease
Anyone can develop Alzheimers disease, but it is more common in older age.
Genetics, lifestyle and health factors are associated with an increased risk of developing dementia.
In a few cases, Alzheimers disease is inherited, caused by a genetic mutation. This is called familial Alzheimers disease, with symptoms occurring at a relatively young age. This is usually when someone is in their 50s, but sometimes younger.
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What Are The First Signs
Mild forgetfulness can be a normal part of the aging process. But when memory problems begin to seriously affect daily life, they could be early signs of Alzheimers disease or another dementia. Here are some of the early warning signs:
- Memory loss
- Poor judgment leading to bad decisions
- Loss of spontaneity and sense of initiative
- Taking longer to complete normal daily tasks
- Repeating questions
- Trouble handling money and paying bills
- Wandering and getting lost
- Losing things or misplacing them in odd places
- Mood and personality changes
The Stages Of Alzheimers Disease
Alzheimers disease causes complex brain changes that may start as much as a decade before identifiable memory and cognitive problems appear.1 If you are in the early stages of Alzheimers disease or care about someone who has this disease, understanding how the disease progresses will help you take the most meaningful steps to support yourself or someone you love.
Before we discuss the stages of Alzheimers disease in full, we should clarify the differences between early- and late-onset. The first symptoms of Alzheimers usually involve memory issues and difficulty with word-finding, spatial logic, and impaired judgment.1 When these arise in someone between the ages of 30 and 60, it is considered early-onset Alzheimers, while symptoms appearing after someone reaches their mid-60s is considered late onset.
According to the National Institute on Aging, the formal stages of Alzheimers include:1
- Preclinical Alzheimers Disease
- Moderate Alzheimers Dementia
- Severe or Final Stage Alzheimers Dementia
Dementia is a medical term describing a group of cognitive symptoms that affect daily function. While there is no cure for Alzheimers, there are medications that can treat symptoms and research ongoing into ways to slow the progression of Alzehimers Disease.
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Slowing The Progression Of Symptoms
The same healthy lifestyle changes that are used to prevent Alzheimers disease can also be useful in slowing the advancement of symptoms.
What Causes Alzheimers Disease
Several processes occur in Alzheimers disease, including amyloid plaque deposits, neurofibrillary tangles and neuronal death.
- Amyloid plaques are deposits outside the brain cells they prevent the brain from passing signals properly.
- Neurofibrillary tangles are deposits inside the brain cells they kill the cells by blocking off food and energy, causing dementia that worsens over time.
- Neuronal death causes shrinking in the outer layer of the brain which is vital to memory, language and judgement Alzheimers disease is characterised by this shrinkage.
In most cases, scientists are still unsure of what triggers the formation of plaques, tangles and other chemical changes associated with sporadic Alzheimer’s disease. Suspected causes include environmental factors, chemical imbalances or the bodys own immune system.
Alzheimers disease tends to target the outer part of the brain first, which is associated with learning and short-term memory. As the disease progresses deeper into the brain, other functions are affected and symptoms get worse.
For people with familial Alzheimers disease, mutations in 3 genes have been found to increase the production of amyloid plaques that damage the brain. There are other ‘risk-factor genes’ that may increase a person’s chance of getting Alzheimers disease earlier in life.
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Can Alzheimer’s Disease Be Prevented
As the exact cause of Alzheimer’s disease is not clear, there’s no known way to prevent the condition.
But there are things you can do that may reduce your risk or delay the onset of dementia, such as:
- staying physically fit and mentally active
These measures have other health benefits, such as lowering your risk of cardiovascular disease and improving your overall mental health.
Read more about preventing Alzheimer’s disease.
Alzheimers Disease Vs Other Types Of Dementia
Dementia is an umbrella term for a range of conditions that involve a loss of cognitive functioning.
Alzheimers disease is the most common type of dementia. It involves plaques and tangles forming in the brain. Symptoms start gradually and are most likely to include a decline in cognitive function and language ability.
To receive a diagnosis of Alzheimers, a person will be experiencing memory loss, cognitive decline, or behavioral changes that are affecting their ability to function in their daily life.
Friends and family may notice the symptoms of dementia before the person themselves.
There is no single test for Alzheimers disease. If a doctor suspects the presence of the condition, they will ask the person and sometimes their family or caregivers about their symptoms, experiences, and medical history.
The doctor may also carry out the following tests:
- cognitive and memory tests, to assess the persons ability to think and remember
- neurological function tests, to test their balance, senses, and reflexes
- blood or urine tests
- a CT scan or MRI scan of the brain
- genetic testing
A number of assessment tools are available to assess cognitive function.
In some cases, genetic testing may be appropriate, as the symptoms of dementia can be related to an inherited condition such as Huntingtons disease.
Some forms of the APOE e4 gene are associated with a higher chance of developing Alzheimers disease.
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Understanding The Different Stages Of Alzheimers Disease
Understanding the different stages of Alzheimers can help you to track the progression of symptoms and plan appropriate care. However, its important to remember that everyone with Alzheimers disease progresses differently and there are steps you can take to slow the onset of symptoms at each stage.
Also, cognitive, physical, and functional phases often overlap, the time in each stage varies from patient to patient, and not everyone experiences all symptoms.
Two commonly used models of Alzheimers progression are the 3-stage model and 7-stage model.