Alzheimer's: Causes, Symptoms, Stages, and Treatments

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- Updated by Jody Mullis, Nutritionist

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 Alzheiner's disease and related dementias are some of the leading causes of death in the Western world. There is growing excitement about the potential for NAD boosters like NMN supplement to play a role in maintaining healthy neurons in the brain, with mouse studies showing that NAD+ precursors restore NAD levels in the brain, with consequent improvements in learning and memory.


Alzheimer’s is a brain disorder classified by neural damage, neuronal tangles, and amyloid plaques that interfere with brain functions. Alzheimer’s causes the brain to deteriorate. Deterioration of the brain causes symptoms such as forgetfulness, difficulty keeping up with a conversation, misplacing objects, and struggling to perform everyday tasks as the disease worsens. It affects the body in later stages, and a person may struggle with simple tasks such as eating food, drinking, walking, and sitting up without help. In later stages, a person loses their ability to remember the names of certain people, may struggle to speak, and requires outside help to take care of them. There are treatments for Alzheimer’s, such as Donepezil, which helps regulate chemicals in the brain; however, these only slow down the symptoms of Alzheimer’s and do not prevent or cure it.


What is Alzheimer's?

Alzheimer’s disease is a disorder of the brain considered to be the most prominent type of dementia. Dementia is a general definition for the loss of ability to perform basic cognitive functions, while Alzheimer’s is considered a cause of dementia. Alzheimer’s symptoms include memory loss, and the inability to carry a conversation or react to environmental stimuli correctly. Alzheimer’s is mainly prevalent in older adults; however, it is not considered a normal part of aging [1]


How common is Alzheimer's?

Alzheimer’s is considered to be the most common form of dementia. In the USA alone, reports from the Alzheimer's Facts and Figures Report in 2019 stated that 5.6 million people over 65 had Alzheimer’s. Women were about 21 percent likely to develop Alzheimer’s, and men were about 11 percent likely to develop Alzheimer’s, meaning that women are twice as likely to develop the condition.


What are the Causes of Alzheimer's?

The causes of alzheimers disease are included below.

  1. Amyloid plaques - Amyloid plaques collect between neurons in the brain and prevent cells from transmitting to each other correctly.
  2. Neurofibrillary tangles - Neurofibrillary tangles occur within the structure of neuron microtubules, interfering with the cell’s ability to transport nutrients and function correctly [2].
  3. Neuronal death - Neuronal death is mainly caused by amyloid plaques disrupting healthy neural functions, resulting in the death of neurons.
  4. Aging and Alzheimer's risk - Aging is a risk factor, as people aged over 65 have more likelihood of developing Alzheimer’s.
  5. Genetics of Alzheimer's disease - Genetics, both mutations, and variants, can affect a person’s likelihood of developing Alzheimer’s.

1. Amyloid plaques

Amyloid plaques are a type of protein, called beta-amyloid, that are known to collect in large clumps, known as plaques, between neurons. These amyloid plaques block neurons from transmitting to one another and disrupt cellular and brain functions. According to the NIH National Library of Aging in 2017, this neural disruption increases symptoms of Alzheimer’s disease. Beta-amyloid 42, a type of amyloid protein, is considered especially harmful as a plaque in an Alzheimer’s brain.


2. Neurofibrillary tangles

Neurofibrillary tangles involve a protein called tau sticking to other tau proteins within the neurons' microtubules, forming a ‘tangle.’ Neurofibrillary tangles block and constrict the pathway of nutrients within neurons, which disrupts neurons from transmitting effectively. In healthy brains, tau typically sticks to microtubules to help stabilize the structure. In alzheimer brains, however, the formation of tau tangles disrupts neurons from performing essential functions, contributing to Alzheimer's symptoms.


3. Neuronal death

Neuronal death involves the brain’s neurons not functioning properly, and not receiving the nutrients they need, resulting in the death of the neuron. Neuronal death is considered, by the NIH National Library of Medicine in 2006, to be mainly caused by amyloid plaques, and can better help us understand what is Alzheimer’s.


4. Aging and Alzheimer's risk

Although age is not a direct cause of Alzheimer’s, older age is typically one of the most significant risk factors. After the age of 65, the risk factor for people developing Alzheimer’s doubles after every additional five years, according to the NIH National Institute on Aging. Age-related brain changes, such as brain shrinkage and vascular damage, help shed light on what causes Alzheimer’s.

5. Genetics of Alzheimer's disease

Two types of genetics contribute to what is Alzheimers, genetic mutations, and genetic variants. Genetic mutations are permanent DNA changes typically inherited from a person’s parents. Genetic variants can be affected by changes in the environment, and lifestyles, such as diet, and smoking. Either of these can contribute to the development of Alzheimer’s disease.


What are the Symptoms of Alzheimer's?

The symptoms of Alzheimer’s are listed below and help explain what is Alzheimer’s disease and how it affects the brain.

  1. Memory lapses - Memory lapses, such as the ability to remember conversations and events, are due to the deterioration of brain cells.
  2. Difficulty concentrating and thinking - Difficulty concentrating and thinking causes people to finish essential tasks much longer.
  3. Making reasonable decisions and judgments in everyday situations - Making reasonable decisions is reduced due to the brain’s deterioration in areas related to remembering and processing information. 
  4. Forgetting how to perform basic tasks [3] - Forgetting how to perform basic tasks, like locking the door, is due to the brain’s loss in areas linked to creating and retrieving memories.
  5. Personality and Behavior changes - Personality and behavior changes, including aggression, depression, and anxiety, are due to a lack of healthy brain cells.
  6. Forgetting well-known individuals or locations - Forgetting well-known individuals or locations is a symptom of severe Alzheimer’s due to significant brain deterioration.


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1. Memory lapses

Memory lapses are a symptom of Alzheimer’s, causing the inability to remember certain conversations, appointments, and dates. Memory lapses also manifest as misplacing items and becoming lost in well-known areas. Memory lapses become a symptom of Alzheimer's due to the rapid deterioration of brain cells.


2. Difficulty concentrating and thinking

Difficulty concentrating and thinking is a symptom of people with Alzheimer’s and causes them to finish routine tasks much longer. Concepts such as numbers are where difficulty in concentration is most prominent. Difficulty concentrating is a symptom of Alzheimer’s due to the damage in the brain's hippocampus, an area dedicated to memories and learning. According to Alzheimer’s statistics from the CDC Centers for Disease Control and Prevention, in 2020, 5.8 million people had cases of Alzheimer’s.


3. Making reasonable decisions and judgments in everyday situations

Making reasonable decisions in everyday situations is reduced while Alzheimer disease is prevalent. Making decisions, also known as having capacity, is how well a person can act in making decisions, as Alzheimer’s affects the brain areas involving remembering and processing information. As Alzheimer’s progresses, the capacity to make a decision is further reduced, according to the Alzheimer’s Society in 2023.


4. Forgetting how to perform basic tasks

Forgetting how to perform basic tasks, such as making a cup of tea or locking the door, are a sign that helps answer is Alzheimer’s a disease. Forgetting how to do basic tasks is a symptom of Alzheimer’s due to the damage in the brain areas associated with creating and retrieving memories.


5. Personality and Behavior changes

Personality and behavior changes are a symptom of Alzheimer’s disease and include becoming aggressive or upset more easily, becoming depressed, difficulty sleeping, and general anxiety. This description of Alzheimer’s disease symptoms, like personality and behavior changes, is due to mass amounts of brain cells dying, so the brain isn’t able to work as well as it used to.


6. Forgetting well-known individuals or locations

Forgetting well-known individuals or locations is a symptom of severe Alzheimer’s, and it’s due to a massive loss of functioning brain cells to be what causes Alzheimer’s disease. Along with forgetting well-known individuals, communication is severely inhibited, and the person may also experience delusions and general agitation.


When do Alzheimer's Symptoms Usually Occur?

Alzheimer’s symptoms usually occur in people 65 years old or older. However, a small fraction of Alzheimer’s disease occurs in people below 65. People with Alzheimer’s symptoms after 65 are considered to have late-onset Alzheimer’s. People who have Alzheimer’s symptoms before the age of 65 are considered to have early-onset Alzheimer’s, which is why it’s essential to know necessary Alzheimer's information to know what types of Alzheimer’s can affect a person.


What are the Risk Factors of Alzheimer's?

There are several risk factors for Alzheimer’s and dementia, according to the NHS in 2021, which are listed below.

  1. Age - Age is a significant risk as many age-related conditions, such as brain shrinkage, occur with age. 
  2. Heredity - Heredity plays a small role in the development of Alzheimer's as there is the possibility of inheriting genes from a person’s parents that could be related to Alzheimer's and dementia.
  3. Down’s Syndrome - Down’s syndrome is linked to Alzheimer’s disease as those with his condition are known to develop Amyloid plaques, which disturb brain function and can lead to Alzheimer’s.
  4. Head injuries - Head injuries Are linked to the increased likelihood of Alzheimer's due to trauma causing long-lasting changes in the brain.
  5. Cardiovascular disease - Cardiovascular disease is a risk factor for Alzheimer’s due to a heart complication, which can decrease oxygen flow to the brain.


1. Age

Age is one of the most prominent risk factors for Alzheimer’s. Age and age-related conditions such as brain atrophy (which the brain shrinks) can contribute to what is Alzheimer's disease [4].


2. Heredity

Heredity can play a role in the development of Alzheimer’s, as you can inherit the genes from your parents that cause the symptoms of Alzheimer's disease description, which are a loss of memory and function due to a steady decline of the brain. Normally, the risk of developing Alzheimer’s from inherited genes is small. However, if a person’s family has more than one case of Alzheimer’s or dementia, the chance of developing it increases.


3. Down's syndrome

The changes a person experiences in their DNA related to Down’s syndrome also create amyloid plaques in the brain. These plaques from Down’s syndrome can aggravate Alzheimer’s disease symptoms, and develop the disease fully due to the brain losing function.


4. Head injuries

Severe head trauma and head injuries have been linked to a higher risk for developing Alzheimer’s and has been noted as an Alzheimer’s disease cause. A study by Penn Medicine in 2021 found that people who experienced a head injury were one and a quarter times more likely to develop dementia later in life.

5. Cardiovascular disease

Cardiovascular disease is a risk factor for Alzheimer’s and can help us understand what type of disease is Alzheimer's disease. The conditions linked to cardiovascular diseases, such as obesity, smoking, and diabetes, along with high blood pressure and cholesterol, can lead to developing Alzheimer’s. This is due to the brain needing a consistent supply of oxygen, and any complication of the heart can lead to a deficiency of oxygen.


What are the Stages of Alzheimer's?

The stages of Alzheimer's, and to understand Alzheimer’s definition, according to WebMD in 2021, are listed below.

  1. Normal Outward Behavior - Normal behavior doesn’t change at this stage, as a PET scan can only detect the disease.
  2. Mild Changes - Mild changes to a person’s behavior may occur, such as misplacing objects.
  3. Mild Decline - Mild decline may occur at this stage, such as asking questions repeatedly.
  4. Moderate Decline - Moderate decline expresses the inability to remember what month it is and difficulty using everyday objects.
  5. Moderately Severe Decline - Moderately severe decline is where a person loses track of where they are and what time it is.
  6. Severe Decline - Severe decline is where a person may begin to confuse people, and experience delusions such as needing to go to work when they don’t have a job.
  7. Very Severe Decline - Very severe decline is where a person can no longer perform basic functions such as sitting up or eating by themselves.

Stage 1: Normal Outward Behavior

The prevalence of Alzheimer’s disease in normal outward behavior is minimal at stage one, without any symptoms. This stage can last for several years. Only a PET scan of the brain can give a person any indication that Alzheimer’s is developing. At this stage, people can generally go about their day without problems.


Stage 2: Very Mild Changes

Mild changes, such as misplacing items or forgetting words that may seem obvious, may develop in a person’s behavior and can indicate Alzheimer’s disease. However, at stage two, a doctor may not pick up on the subtle changes, and a person can still continue their life independently, without issue.


Stage 3: Mild Decline

Mild decline, stage three of what is Alzheimer's disease, begins to express noticeable changes in a person’s behavior. People with stage three Alzheimer’s may show symptoms of forgetfulness, such as forgetting what they just read, asking questions repeatedly, having difficulties making plans, and having the inability to remember new names. Although they can still live independently, a person may benefit from outside help, aiding in places where their memory might be weak.


Stage 4: Moderate Decline

Stage four of Alzheimer’s disease definition is when a person forgets information about themselves and forgets what month it is. They may have difficulty cooking or ordering from a menu, using day-to-day objects such as phones, and understanding what other people say. People with stage four, experiencing a moderate decline, may need more outside help, such as having someone else drive for them and do household chores.


Stage 5: Moderately Severe Decline

Stage five, or a moderately severe decline in Alzheimer’s, is when a person has severe memory issues, with women being affected more than men from Alzheimer’s disease statistics. Symptoms of stage five include losing track of what time it is, or where the person is. They may also struggle with choosing the appropriate clothes for the day or the month. They may also repeat questions just to know someone else is with them. A person with stage five may benefit from having someone else choose their clothes for them, and may not be able to live independently.


Stage 6: Severe Decline

Stage six of Alzheimer’s involves a severe decline of mental processes. A person with stage six may experience forgetting the names of close people, or confusing people. They may also experience delusions, such as needing to get ready for work, even if they don’t have a job. They may no longer have the ability to go to the bathroom by themselves anymore or have the ability to carry a conversation. They demonstrate what are the symptoms of Alzheimer’s in stage six with difficulty swallowing, feeding themselves, and putting on clothes by themselves. They may also experience difficulty walking, and sleeping issues. They need someone to care for them, as they are no longer able to care for themselves.


Stage 7: Very Severe Decline

Stage seven of Alzheimer's is a very severe decline in mental and physical processes, and a person loses the ability to eat, walk, or sit up without aid. They also may no longer be able to tell if they are thirsty and need someone else to feed them soft foods and give them something to drink. Aid from loved ones or caregivers around the clock is what a person with stage seven Alzheimer’s needs, as they can no longer care for themselves.

What are the Complications of Alzheimer's?

The complications of Alzheimer’s are listed below.

  • Aspiration, or inhaling food or drink into the lungs.
  • Flu or other infections like pneumonia may be more common is dementia alzheimers type.
  • Falls, due to a lack of coordination.
  • Fractures from falls.
  • Bedsores due to lying in bed for long hours.
  • Dehydration or malnutrition from a lack of a proper diet.


How does Alzheimer's affect the Body?

Alzheimer’s affects the body during its last stages with the inability to swallow correctly, being able to balance, and being able to control the bowel and bladder. These symptoms of all timers disease usually only occur in stage five or later due to brain impairment and deterioration.


How does Alzheimer's affect the Brain?

Alzheimer’s affects the brain by breaking down neurons and neural pathways. The breakdown of neurons eventually causes parts of the brain to shrink, according to the NIH National Institute on Aging in 2017. Alzheimer’s affects about 5.8 million people in the USA, helping us understand how common is Alzheimer’s.


How does Alzheimer's affect Lifestyle?

Alzheimer’s affects lifestyle mainly from its memory loss symptoms, as people begin to lose track of where they are, and what they’re doing, and can become lost. They may also struggle with handling money and take longer to do basic tasks by themselves, necessitating someone to be there with them. To better understand what kind of disease is Alzheimer’s, it’s essential to keep in mind that Alzheimer’s mainly affects the brain due to deteriorating neurons, which leads to impairment in memory and thought processes.


How is Alzheimer's Diagnosed?

Alzheimer’s is diagnosed with various tests by a doctor. Alzheimer’s patients will undergo tests involving memory, thought processes, and behavior. Laboratory tests that help diagnose Alzheimer’s include brain scans, such as PET scans, MRI scans, and CT scans.


How is Alzheimer's Prevented?

Alzheimer’s may be prevented by limiting a person’s susceptibility to cardiovascular disease. Healthy, preventative measures a person can take to help prevent Alzheimer’s disease prevalence in their life is by quitting smoking and alcohol, eating healthy, and exercising. 


What are the Treatments available for Alzheimer's?

Treatments for Alzheimer’s and minimizing the cause of Alzheimer’s are listed below.

  1. Donepezil (Aricept) - Donepezil is a cholinesterase inhibitor that helps slow down the rate of brain deterioration.
  2. Galantamine (Razadyne) - Galantamine is also a cholinesterase inhibitor that works similarly to Donepezil. 
  3. Rivastigmine (Exelon) - Rivastigmine is also a cholinesterase inhibitor that works similarly to Donepezil and Galantamine.
  4. Aducanumab - Aducanumab inhibits beta-amyloid, a protein known for clumping in the brain and disrupting brain function in Alzheimer’s patients.
  5. Memantine - Memantine regulates glutamate, a chemical involved in various brain activity.


1. Donepezil (Aricept)

Donepezil is a cholinesterase inhibitor that helps the brain slow down from processing acetylcholine, a compound necessary for memory and alertness. Donepezil cannot stop Altimers from spreading as the brain loses cells that produce acetylcholine, but it can slow down the rate at which Alzheimer’s spreads. Donepezil can help treat all stages of Alzheimer’s and is taken once daily.


2. Galantamine (Razadyne)

Galantamine is a cholinesterase inhibitor that works similarly to Donepezil and is used to treat mild or moderate cases of Alzheimer's. It can be taken once a day, or twice a day with extended-release capsules.


3. Rivastigmine (Exelon)

Rivastigmine is a cholinesterase inhibitor that works similarly to Donepezil and Galantamine for treating dementia and Alzheimer’s. It is taken as a pill for mild cases of Alzheimer's, or as a skin patch for severe cases.


4. Aducanumab

Aducanumab helps treat Alzheimer's by limiting brain beta-amyloid, a protein responsible for creating amyloid plaques that are considered to be a significant part of brain decline. Aducanumab is only approved, currently, for people with mild cases of Alzheimer’s, and it causes side effects such as brain swelling.


5. Memantine

Memantine helps treat Alzheimer’s and helps us understand is Alzheimer’s a disease by regulating glutamate, which is a chemical involved in learning and memory functions. Memantine may cause side effects such as dizziness and confusion.


How does Donepezil help with Alzheimer's?

Donepezil helps with Alzheimer’s by reducing some of the cognitive symptoms associated with Alzheimer’s, according to the NIH National Institute on Aging in 2021. Donepezil helps the brain slow down from processing acetylcholine, a key component in the thought process and memory function. Although it can only slow down the rate at which Azhimers’ progresses, as brain cells will continue to die and stop producing acetylcholine, it can help mitigate symptoms for mild and moderate cases of Alzheimer’s vs dementia.


What to Expect in Alzheimer's Condition?

A person can expect to experience forgetfulness in the early stages of Alzheimers age and condition. A person can also expect to experience difficulty learning new things, or the ability to concentrate. In later stages, a person can expect difficulty walking or sitting up alone. They may also experience an inability to swallow or control their bladder properly.


How Long Does Alzheimer's Last?

Alzheimer’s lasts anywhere between four to eight years after a person is initially diagnosed, according to the Alzheimer’s Association in 2023. Some people diagnosed with Alzheimer’s have lived as long as 20 years after, which can help give us the definition Alzheimer's as a disease that worsens over time but impacts everyone differently.


What are Other Types of Alzheimer's?

There are two types of Alzheimer’s, early-onset Alzheimer's, and late-onset Alzheimer's.

  • Early onset Alzheimer’s affects people before the age of 65, is rare and is usually related to genetics.
  • Late-onset Alzheimer's affects people after the age of 65 and is related to other factors such as age-related conditions like brain atrophy. 

Dementia should not be considered a type of Azhiemrs in the debate between Alzheimer’s disease vs dementia. Dementia, instead, is a condition of the brain, and Alzheimer's is a cause of dementia.


Can an individual with Alzheimer's undergo surgery?

Yes, an individual with Alzheimer’s can undergo surgery if it will improve their quality of life. However, a person with Alzheimer’s brain will react to sugar differently than a person without Alzheimer's. The one caring for the Alzheimer’s patient will want to ask the doctor if the surgery and anesthesia will affect a person with dementia, and how the surgery will proceed, before going ahead.

Is Alzheimer's Curable?

Currently, there is no cure for Alzheimer’s disease. However, there are medicines available that help reduces or slow down symptoms. There are also support systems in place so a person can get aid and Alzheimer's information with caring for someone with Alzheimer’s.


What is the difference between Alzheimer's vs. Dementia?

To learn the difference between dementia vs. Alzheimer's Disease, it’s essential to understand that dementia is a general term for brain decline, while altimers disease is a specific disease. Alzheimer's gives symptoms such as forgetfulness that can cause dementia, and help us better understand dementia vs. Alzheimer's Disease