What is Alzheimer's Disease? Why Does It Happen? What Are The Symptoms?

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What is Alzheimer's Disease? Why Does It Happen? What are the symptoms? We will talk about the details on the subject in our article titled. Alzheimer's disease causes decline in memory, thinking, learning and organizing skills over time. Alzheimer's is the most common cause of dementia and usually affects people over the age of 65. There is no cure for Alzheimer's, but some medications and therapies can help temporarily manage symptoms.

What is Alzheimer's Disease?

Alzheimer's disease; It is a brain disorder that causes a progressive decline in memory, thinking, learning and organizing skills. It eventually affects a person's ability to perform basic daily activities. Alzheimer's disease is the most common cause of dementia. Alzheimer's symptoms worsen over time. Researchers believe that the disease process may begin 10 years or more before the first symptoms appear. Alzheimer's most commonly affects people over the age of 65.

What's the Difference Between Alzheimer's and Dementia?

Dementia describes the state of a person's mental function. It is not a specific disease. Dementia refers to a decline in mental functioning from a previously higher level that is severe enough to interfere with daily life.

A person with dementia has two or more of these specific difficulties, including a change or decline in:

  • Memory
  • Reasoning and tackling complex tasks
  • Language
  • Understanding the relationship between visual form and space
  • Behavior and personality

The severity of dementia varies. In the mildest stage, a slight decline in mental functions may be noticed and some help with daily tasks may be needed. In the most severe stage, the person becomes completely dependent on others for help with simple daily tasks.

Dementia; It develops when infections or diseases affect parts of the brain involved in learning, memory, decision-making, or language. Alzheimer's disease is the most common cause of dementia, accounting for at least two-thirds of dementia cases in people aged 65 and over.

Other common causes of dementia include:

  • Vascular dementia
  • Dementia with Lewy bodies
  • Frontotemporal dementia
  • Dementia due to Parkinson's disease

Who Does Alzheimer's Disease Affect?

Alzheimer's disease mostly affects people over the age of 65. The older a person is, over 65, the more likely they are to develop Alzheimer's. In some people, Alzheimer's disease develops before age 65, typically in their 40s or 50s. This is called early-onset Alzheimer's disease. This condition is rare. Less than 10% of Alzheimer's cases have early onset.

How Common Is Alzheimer's Disease?

Alzheimer's disease is common. It affects approximately 24 million people worldwide. One in every 10 people over the age of 65 and approximately one third of people over the age of 85 have this disease.

What are the Stages of Alzheimer's Disease?

Institutions and doctors working on Alzheimer's disease use various terms to describe the stages of Alzheimer's disease based on symptoms. Although the terms vary, the stages all follow the same pattern, and Alzheimer's symptoms gradually worsen over time. Yet no two people experience Alzheimer's the same way. Each person with Alzheimer's disease will progress through the stages at different rates. Not all changes will occur in every person. Because the stages can overlap, it can sometimes be difficult for doctors to place a person with Alzheimer's in a particular stage.

Some organizations and doctors frame the stages of Alzheimer's disease in terms of dementia:

  • Preclinical Alzheimer's disease
  • Mild cognitive impairment due to Alzheimer's disease
  • Mild dementia due to Alzheimer's disease
  • Moderate dementia due to Alzheimer's disease
  • Severe dementia due to Alzheimer's disease

Other organizations and doctors explain the stages more broadly:

  • Light
  • Middle
  • Severe


  • Early
  • Middle
  • Late

When doctors use certain words to describe the stages of Alzheimer's, feel free to ask what they mean.

What is Preclinical Alzheimer's Disease?

Doctors often refer to only the preclinical stage in research on Alzheimer's disease. People with preclinical Alzheimer's typically have no symptoms (asymptomatic) but have changes in their brains. This stage can last for years or even decades. People at this stage are usually not yet diagnosed with Alzheimer's because they are functioning at a high level.

There are now brain imaging tests that can detect a buildup of a protein called amyloid in the brain that interferes with the brain's communication system before symptoms begin.

What is Mild Cognitive Impairment Due to Alzheimer's Disease?

When memory problems become noticeable, the doctor usually describes it as mild cognitive impairment. This means a slight decline in mental abilities compared to others of the same age. If a person is in the early stages of Alzheimer's, they may notice a slight decline in their abilities. Others close to the patient may notice and point out these changes. However, these changes are not serious enough to affect daily life and activities. In some cases, a treatable disease or the effects of the disease cause mild cognitive impairment. However, for most people with mild cognitive impairment, this is a point on the path to dementia.

Researchers consider mild cognitive impairment as the stage between the mental changes seen in normal aging and early-stage dementia. Various diseases, including Alzheimer's or Parkinson's disease, can cause mild cognitive impairment. Similarly, dementia can have various causes.

What are the Signs and Symptoms of Alzheimer's Disease?

Signs and symptoms of Alzheimer's disease vary depending on the stage of the condition. In general, Alzheimer's symptoms include a gradual decline in some, most, or all of the following:

  • Memory
  • Reasoning and tackling complex tasks
  • Language
  • Understanding the relationship between visual form and space
  • Behavior and personality

People with memory loss or other symptoms of Alzheimer's may have trouble recognizing their mental decline. These symptoms may be more pronounced for loved ones. Anyone experiencing dementia-like symptoms should see a healthcare professional as soon as possible.

What Are the Symptoms of the Mild Stage of Alzheimer's Dementia?

Alzheimer's symptoms become noticeable in the mild phase. The most common early symptom is forgetting newly learned information, especially recent events, places, and names.

Other signs and symptoms of mild Alzheimer's include:

  • Difficulty finding the right words to express thoughts.
  • Losing or misplacing objects more than usual.
  • Difficulty making plans or being organized.
  • Having difficulty in problem solving.
  • Takes longer to complete routine daily tasks.

Most people with mild Alzheimer's have no trouble recognizing familiar faces and can often travel to familiar places.

What Are the Symptoms of the Middle Stage of Alzheimer's?

Moderate Alzheimer's is typically the longest stage and can last for many years. People in the middle stage of Alzheimer's often need care and help.

People in this stage may:

  • Memory loss and confusion increase, and they often forget events or details about their lives, such as phone numbers or where they went to school.
  • Confusion may increase about what day of the week it is, what season they are in, and where they are.
  • Their short-term memory is weak.
  • Has difficulty getting to know friends and family.
  • They repeat stories, thoughts or events in their minds.
  • They have difficulty with simple mathematics.
  • They need help with self-care such as bathing, showering and using the toilet.
  • They experience more personality changes, such as being agitated or acting out. As the disease progresses, they may show depression, apathy, or anxiety.
  • They may develop unfounded suspicions (delusions) about family, friends and caregivers.
  • They may develop urinary and/or stool (bowel) incontinence.
  • Experiences sleep disorders.
  • They begin to move away from their living spaces.

What are The Symptoms Of The Severe Phase of Alzheimer's?

In the final stages of Alzheimer's, symptoms of dementia are severe. People at this stage need intensive care.

In the severe stage of Alzheimer's disease, a person usually:

  • Experiences almost complete memory loss.
  • He is not aware of his surroundings.
  • Needs help with all basic activities of daily living, such as eating, sitting and walking.
  • Loses the ability to communicate. Their speech becomes limited to a few words or sentences.
  • Becomes vulnerable to infections, especially pneumonia and skin infections.
  • Hospice care may be appropriate for comfort during this period.

What Causes Alzheimer's Disease?

Abnormal protein accumulation in the brain causes Alzheimer's disease. The accumulation of these proteins (amyloid protein and tau protein) leads to the death of brain cells. The human brain contains more than 100 billion nerve cells and other cells. Nerve cells work together to provide all the communication needed to perform functions such as thinking, learning, remembering and planning.

Scientists believe that amyloid protein builds up in brain cells, forming larger masses called plaques. Twisted fibers of another protein called tau turn into tangles. These plaques and tangles block the communication between nerve cells, preventing them from performing their operations. The slow and continued death of nerve cells results in the symptoms of Alzheimer's disease. Nerve cell death begins in one area of the brain (usually the hippocampus, the part of the brain that controls memory) and then spreads to other areas. Despite ongoing research, scientists still don't know exactly what causes these proteins to form. It is believed that a genetic mutation can cause early-onset Alzheimer's. Late-onset Alzheimer's is thought to occur due to a complex series of brain changes that can occur over decades. A combination of genetic, environmental, and lifestyle factors likely contribute to the cause.

Is Alzheimer's Hereditary?

Researchers do not know why some people get Alzheimer's disease and others do not. However, several factors have been identified that increase the risk of Alzheimer's, including genetic (inherited) factors.

  • Having one form of the apolipoprotein E (APOE) gene increases the risk. There are several forms of this gene, and one of them, APOE ε4, increases the risk of developing Alzheimer's and is also associated with an earlier age of onset of the disease. However, having the APOE ε4 form of the gene does not guarantee that you will get the disease. Some people without APOE ε4 may also develop Alzheimer's.
  • Those who have a first-degree relative (biological parent or sibling) with Alzheimer's disease have a 10% to 30% increased risk of developing the disease. People who have two or more siblings with late-onset Alzheimer's disease are three times more likely to develop the disease than the general population.
  • Having trisomy 21 (Down syndrome) also increases the risk of early-onset Alzheimer's.

How Is Alzheimer's Disease Diagnosed?

Doctors use a variety of methods to determine whether a person with memory problems has Alzheimer's disease. This is because many other conditions, especially neurological conditions, can cause dementia and other symptoms of Alzheimer's.

In the first steps of diagnosing Alzheimer's, a doctor will ask questions to better understand a person's health and daily life. The doctor may also ask someone close to the patient, such as a family member or caregiver, for information about their symptoms. The doctor may ask the relatives of the patient:

  • General health status
  • Current medications
  • Medical history
  • Ability to perform daily activities
  • Mood, behavior and personality changes

A doctor may also:

  • Physical examination and neurological examination.
  • A mental status exam that includes tests to evaluate memory, problem solving, attention, basic math, and language
  • Standard medical tests, such as blood and urine tests, to rule out other possible causes of symptoms
  • Brain imaging tests, such as brain computed tomography, brain MRI, or positron emission tomography (PET), to support a diagnosis of Alzheimer's or rule out other possible conditions

What is the Treatment for Alzheimer's Disease?

There is no cure for Alzheimer's disease, but some medications can temporarily slow the worsening of dementia symptoms. Medications and other interventions can also help with behavioral symptoms. Starting treatment for Alzheimer's as early as possible may help maintain daily functions for a while longer. But current medications do not stop or reverse Alzheimer's. Because Alzheimer's affects everyone differently, treatment is highly individualized. Doctors work with Alzheimer's patients and their caregivers to determine the best treatment plan.

The U.S. Food and Drug Administration (FDA) has approved two types of drugs to treat the symptoms of Alzheimer's disease:

  • Cholinesterase inhibitors
  • NMDA antagonists

The FDA has granted accelerated approval for aducanumab, the first disease-modifying therapy for Alzheimer's disease. The medication helps reduce amyloid deposits in the brain. Aducanumab is a new drug, and researchers have studied its effects in people living with early Alzheimer's disease. Therefore, the drug can only help people in the early stages.

Cholinesterase Inhibitors

The following cholinesterase inhibitors may help treat symptoms of mild to moderate Alzheimer's disease:

  • Donepezil (This is also FDA-approved to treat moderate to severe Alzheimer's.)
  • Rivastigmine
  • Galantamine

These medications work by blocking the action of acetylcholinesterase, the enzyme responsible for destroying acetylcholine. Acetylcholine is one of the chemicals that helps nerve cells communicate. Researchers believe that decreased acetylcholine levels cause some symptoms of Alzheimer's disease.

These medications may improve some memory problems and reduce some behavioral symptoms of Alzheimer's disease. These medications do not cure Alzheimer's disease or stop the progression of the disease.

NMDA Antagonists

Memantine is FDA-approved for the treatment of moderate to severe Alzheimer's disease. It helps certain brain cells stay healthier. Studies have shown that Alzheimer's patients taking memantine perform better in activities of daily living such as eating, walking, toileting, bathing and dressing.

Managing Behavior Changes

If your loved one has been diagnosed with Alzheimer's disease, you can take steps to make them comfortable in their environment and help manage behavioral changes. For this, the following can be done:

  • To provide a familiar environment for them. Not changing the layout or organization of living spaces.
  • To take care of their comfort.
  • Providing them with comforting objects, such as a favorite stuffed animal or blanket.
  • Trying to divert his attention if he is under stress.
  • To enable them to avoid confronting the disease.

No medications are approved for the management of behavioral symptoms in Alzheimer's dementia. Some medications may help some people:

  • Antidepressants: These medications can treat anxiety, restlessness, aggression, and depression.
  • Anti-anxiety medications: These medications can treat agitation.
  • Anticonvulsant medications: These medications can sometimes treat aggression.
  • Antipsychotics (neuroleptics): These medications can treat paranoia, hallucinations, and agitation.

These medications can cause unpleasant or potentially dangerous side effects (such as dizziness, which can lead to falls), so doctors usually prescribe them for short periods only when behavior problems are severe. These medications are prescribed only after trying safer non-drug treatments.

Clinical Trials

Scientists are actively researching Alzheimer's disease and possible treatments. The patient's doctor can be consulted to see if there are any clinical studies that may benefit the patient or their relatives. Early diagnosis often provides people with more opportunities to participate in clinical trials or other research studies.

How Can the Risk of Getting Alzheimer's Disease Be Reduced?

While there are some risk factors for Alzheimer's that cannot be changed, such as age and genetics, other factors can be managed to help reduce the risk.

Risk factors for Alzheimer's disease include:

  • Age (increasing age is the main risk factor)
  • Genetics
  • Traumatic head injury
  • Depression
  • Cardiovascular disease and cerebrovascular disease.
  • High blood pressure
  • High cholesterol
  • Diabetes
  • Smoking
  • Obesity

Research shows that having a healthy lifestyle helps protect the brain from cognitive decline. The following strategies may help reduce the risk of developing Alzheimer's disease:

  • Staying mentally active: Playing board games, reading books, solving puzzles, playing a musical instrument or taking up other hobbies that require "brain power".
  • Being physically active: Exercise increases blood flow and oxygen to the brain, which can affect brain cell health. A person should wear protective headgear if participating in activities that increase the risk of head injury.
  • Staying socially active: Talking regularly with friends and family, participating in group activities such as exercise classes, book clubs or volunteering in the community.
  • Eating healthy: Following the Mediterranean or DASH diet or another healthy diet containing antioxidants. Consume alcoholic beverages in moderation.

Those who are concerned about their risk of developing Alzheimer's disease should contact a healthcare professional.

What to Expect for Those with Alzheimer's Disease?

It's important to remember that no two people with Alzheimer's disease are affected in the same way. It is difficult to predict how a person will be affected by this disease. The best way to prepare is to talk to doctors who specialize in the research and treatment of Alzheimer's disease and dementia. As the situation progresses, a team that can meet the individual's needs may be utilized.

How Long Do Alzheimer's Patients Live?

The prognosis (course of the disease) for Alzheimer's disease is generally poor. The course of the disease varies from person to person, but on average, people with Alzheimer's over the age of 65 die within four to eight years after diagnosis. However, some people can live up to 20 years after the first symptoms appear.

Common causes of death include:

  • Pneumonia
  • Malnutrition and dehydration
  • Other infections

Alzheimer's disease is the seventh leading cause of death in the United States.

How to Care for a Person with Alzheimer's Disease?

Caring for someone with Alzheimer's can have significant physical, emotional, and financial costs. The following tips can help both the patient and their relatives:

  • Learning about Alzheimer's disease: Understanding the condition is an important long-term strategy for helping a loved one with Alzheimer's. Efforts should be made to find programs that teach families the various stages of Alzheimer's and ways to cope with and manage its symptoms.
  • Tracking a person's symptoms: Keeping a diary of a person's mental, emotional, and behavioral changes with Alzheimer's disease can help the healthcare team determine the next steps in their care. If significant or concerning changes are noticed, the healthcare team should be contacted.
  • Managing stress: Caring for someone with Alzheimer's can be stressful and tiring. A network of friends and family should be created to support the patient's relatives in order to apply healthy coping skills.
  • Joining a support group: Alzheimer's disease support groups can help a person feel less alone when caring for someone with Alzheimer's. Concerns can be voiced and experiences shared. In addition, useful strategies for caring for the sick person can be learned.

When Should You Visit a Doctor?

If a person or a loved one is having problems with memory or thinking, they should see a healthcare professional. Doctors can determine whether the problems are caused by Alzheimer's or another condition. If a person or a loved one has been diagnosed with Alzheimer's, it will be necessary to see their healthcare team regularly to monitor the progress of the condition and to make sure the care plan is working.

What Questions Should Be Asked to the Doctor?

If a person has a relative with Alzheimer's disease and that person provides communication between the doctor and the patient, it may be useful to ask the doctor the following questions:

  • How does Alzheimer's disease usually progress?
  • What signs and symptoms should you pay attention to?
  • What treatments are available for Alzheimer's, what do you recommend?
  • Are there any clinical studies available?
  • Where is the best place to care for the patient?
  • What needs to be done to make the patient's living space safe and comfortable?
  • What services and support organizations are available in your area?
  • Am I at risk of developing Alzheimer's disease? Does this disease run in families?

Learning that a loved one has Alzheimer's can be very difficult. It should be known that the healthcare team will assist the patient and their relatives throughout the process and provide individualized options for care. It is important for patients' relatives to also pay attention to themselves. Relatives of patients should consider joining support groups or creating their own support network to help them.