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Alzheimer's

Last Updated: February 15, 2024

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Understanding Alzheimer's: Gain insights into the causes, symptoms, and potential treatments for this complex and challenging neurodegenerative disease.

Alzheimer's Explained

Alzheimer's disease is a progressive and chronic neurological condition that causes the deterioration of brain cells, leading to brain shrinkage and nerve cell death.

This degeneration primarily affects the regions of the brain responsible for memory and thinking, resulting in irreversible and severe cognitive impairments.

The symptoms of Alzheimer's disease gradually worsen over time, interfering with the affected individual's ability to carry out daily activities independently.

Alzheimer's disease is the most prevalent cause of dementia, responsible for 60 to 80 percent of cases.

Dementia is a general term describing a decline in cognitive function, memory, thinking, and behavior to the extent that it interferes with the ability to perform daily tasks. Dementia is not a specific disease but a group of symptoms that different underlying disorders can cause.

The onset of Alzheimer's disease is typically gradual, and the early symptoms may be mistaken for normal aging or stress.

As the disease progresses, the symptoms become more severe, affecting memory, language, judgment, and personality, eventually leading to complete dependence on caregivers.

Currently, there is no cure for Alzheimer's, with treatments focused on managing symptoms and improving the individual's quality of life.

History of Alzheimer’s Disease

The neurodegenerative disorder was first described by Alois Alzheimer in 1906.

Alois, a psychiatrist and neuroanatomist, reported a case of a 50-year-old woman who suffered from memory loss, delusions, hallucinations, aggression, and confusion, which worsened until her death five years later. In her autopsy, he identified the hallmarks of Alzheimer's disease: plaques and tangles.

Although Alzheimer's disease was once considered a rare form of dementia, neurologist Robert Katzman's landmark editorial in 1976 changed the perspective. Katzman described Alzheimer's as a "major killer" and a public health challenge affecting many worldwide.

Organizations were formed to raise funds for research and increase awareness for those affected by the disease.

Since then, over 45,000 articles have been published on Alzheimer's, investigating its cause, effects, and potential treatments. Efforts are also being made to improve the quality of life for people with Alzheimer's, including person-centred care in long-term facilities.

Types of Alzheimer's Disease

Alzheimer's disease can be classified into two main types: sporadic Alzheimer's disease and familial Alzheimer's disease.

Sporadic Alzheimer's Disease

Sporadic Alzheimer’s is the most common form of Alzheimer's disease and is not linked to any specific family history. It is believed to be caused by genetic, environmental, and lifestyle factors.

Research has shown that age is the most significant risk factor for developing sporadic Alzheimer's disease, with onset typically occurring after ages 60-65.

Familial Alzheimer's Disease (FAD)

FAD is a rare form of Alzheimer's disease inherited directly from parents to their children. FAD accounts for less than 5% of all cases and is caused by specific genetic mutations that lead to the development of the disease.

People with FAD have a 50% chance of passing the disease-causing gene to their children. FAD has the same symptoms as sporadic Alzheimer's, but onset can occur at any age, even in individuals in their 30s or 40s.

While there is currently no cure for FAD, genetic testing can help identify individuals at risk of developing the disease, and early intervention may help slow its progression.

Causes of Alzheimer's Disease

The most significant risk factor is age, with the likelihood of developing Alzheimer's disease increasing significantly after age 65. Other risk factors include genetics, environmental factors, and lifestyle factors.

Genetics and Alzheimer's Disease

Researchers have identified genes linked to Alzheimer's disease that control how every cell in the body works, increasing the risk of getting certain diseases, including Alzheimer's. There are two types of genes related to Alzheimer's disease: risk and deterministic.

Risk genes, such as apolipoprotein E (APOE), increase the likelihood of getting Alzheimer's disease.

Carrying one APOE e4 gene doubles or triples the risk of getting Alzheimer's while having two genes further increases the risk.

Lifestyle, race, ethnicity, and environment also play a role in getting the disease; having APOE e4 genes does not necessarily mean an individual will develop Alzheimer's.

In addition to APOE, researchers have identified links between late-onset Alzheimer's and other genes, such as ABCA7, CLU, CR1, PICALM, PLD3, TREM2, and SORL1.

Changes in these genes may increase the risk of Alzheimer's, but not everyone with a changed gene will get Alzheimer's disease.

Deterministic genes guarantee that any person who inherits the gene will develop Alzheimer’s.

Few individuals with Alzheimer's disease have the young-onset type, which is strongly linked to genes. Scientists have found three genes that cause early-onset Alzheimer's, including Amyloid precursor protein (APP), Presenilin 1 (PSEN1), and Presenilin 2 (PSEN2).

These genes account for about half of the cases of early-onset Alzheimer's disease. While most experts do not routinely recommend genetic testing for late-onset Alzheimer's disease, testing may be helpful in certain instances of early-onset Alzheimer's disease.

Environmental Factors and Alzheimer's Disease

While genetic factors have been implicated in the development of Alzheimer’s, there is growing evidence to suggest that environmental factors may also play a role.

Several studies have explored the association between environmental risk factors and the onset of Alzheimer’s. These risk factors include exposure to:

  • Electromagnetic fields (EMF): EMF has been the most investigated environmental risk factor studied. It has been reported to affect several processes within the body, including calcium homeostasis and melatonin production in the brain. Individuals with medium to high EMF exposure are two to three times more likely to develop the condition than those with low to low exposure.
  • Solvents: Some studies have suggested that exposure to solvents may result in neurotoxicity and cognitive impairment.
  • Heavy metals: Exposure to heavy metals, such as lead, has resulted in epigenetic modifications of Alzheimer’s-related genes and dysregulated expression later in life.

Lifestyle Factors and Alzheimer's Disease

Growing evidence shows that maintaining healthy lifestyle factors is critical in reducing the risk of Alzheimer's disease and other forms of dementia.

  • Genetics: Several studies have shown that individuals who follow healthy lifestyles are less likely to develop Alzheimer's disease, even if they have a genetic predisposition.
  • Eating Habits: One large study conducted at Vanderbilt University Medical Center found that individuals who followed a Mediterranean-style diet rich in fruits, vegetables, whole grains, and fish had a lower risk of developing Alzheimer's disease than those who did not.
  • Exercise: Another study found that regular exercise and healthy lifestyle factors were associated with a lower risk of Alzheimer's disease, improving cognitive function in individuals with mild cognitive impairment.
  • Sleep: Chronic sleep deprivation and poor sleep quality have been linked to an increased risk of Alzheimer's disease, as sleep is important for the brain to clear away harmful proteins such as beta-amyloid.

Behavioral Symptoms

Behavioral symptoms are common in people with Alzheimer's and can be distressing for those with the disease and their caregivers. These symptoms can include aggression, agitation, wandering, depression, anxiety, and changes in sleep patterns.

In the early stages of the disease, individuals may experience mood swings or become irritable or apathetic. As the disease progresses, these symptoms may become more pronounced and disruptive to daily life.

Agitation and aggression can be particularly challenging for caregivers to manage. These behaviors may be triggered by confusion or frustration with daily tasks or social situations and can be exacerbated by environmental factors such as noise or overstimulation.

People with Alzheimer's may also wander or become disoriented, which can be dangerous if they cannot find their way back home.

Caregivers may need to implement safety measures to prevent falls or accidents, such as installing door locks or using GPS tracking devices.

Changes in sleep patterns are also common in Alzheimer's disease, with individuals experiencing sleep disturbances, nighttime wandering, or daytime napping. These changes can lead to fatigue, decreased alertness, and increased behavioral symptoms during waking hours.

Caregivers may need to establish a consistent sleep schedule, minimize daytime napping, and create a comfortable sleep environment to help manage these symptoms.

Diagnosis

When diagnosing Alzheimer's, healthcare providers utilize several methods and tools to determine whether a person with memory or cognitive problems has the disease.

They begin by interviewing the individual experiencing symptoms and a family member or friend to gather information on their overall health, medication use, past medical history, ability to carry out daily activities, and behavioral changes.

The healthcare provider will also conduct tests to assess memory, attention, language, problem-solving, and counting. They may order standard medical tests such as blood and urine tests to identify other possible causes of the problem.

Psychiatric evaluations may also be conducted to rule out underlying mental health conditions.

To support an Alzheimer's diagnosis or rule out other possible causes for symptoms, healthcare providers may perform brain scans such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET).

They may also collect cerebrospinal fluid (CSF) via a spinal tap to measure the levels of proteins associated with Alzheimer’s and related dementias. Healthcare providers may repeat these tests to determine how the person's memory and cognitive functions change.

Early diagnosis of Alzheimer's disease is crucial. While there is no cure for Alzheimer's, medicines are emerging to treat the progression of the disease, and some medications can help manage the symptoms.

Early diagnosis allows people with Alzheimer's and their families to plan for the future, care for financial and legal matters, address potential safety issues, learn about living arrangements, and develop support networks.

Specialists such as geriatricians, geriatric psychiatrists, neurologists, and neuropsychologists can offer detailed diagnoses or further assessments.

Memory clinics and centers, including Alzheimer’s Disease Research Centers, can also provide diagnostic services with access to advanced diagnostic tests.

Disease Progression

Alzheimer's is a progressive disorder that gradually worsens over time. The rate of progression can vary from person to person.

Moderate Alzheimer's Disease

Moderate Alzheimer's disease typically involves more severe memory loss and confusion.

People with moderate Alzheimer's may begin to have difficulty recognizing family members and friends, have trouble with speech and language, experience personality changes, and require more assistance with daily activities.

Severe Alzheimer's Disease

Severe Alzheimer's disease is the advanced stage, characterized by a significant decline in cognitive function, including the ability to communicate, move independently, and care for oneself.

People with severe Alzheimer's may be unable to recognize family members and may lose the ability to speak, eat, and swallow. They may also experience incontinence and require assistance with all activities of daily living, including eating, bathing, and dressing.

In this stage, individuals may become bedridden and require around-the-clock care.

Early Onset Alzheimer's Disease

Early onset Alzheimer's disease is a type of Alzheimer's that occurs before the age of 65. It is less common than late-onset Alzheimer's and is often caused by a genetic mutation.

People with early onset Alzheimer's may experience memory loss, confusion, difficulty with problem-solving and planning, and changes in mood and behavior. They may also have difficulty with speech and language and experience personality changes.

The progression of the disease in individuals with early-onset Alzheimer's may be faster than in those with late-onset Alzheimer's.

Late-onset Alzheimer's Disease

Late-onset Alzheimer's disease is the most common form of Alzheimer's and usually occurs after age 65. While the exact cause of late-onset Alzheimer's is unknown, it is thought to be a combination of genetic, environmental, and lifestyle factors.

Symptoms of late-onset Alzheimer's may include memory loss, confusion, difficulty with problem-solving and planning, and changes in mood and behavior. People with late-onset Alzheimer's may also have speech and language difficulties, experience personality changes, and require assistance with daily activities.

The progression of the disease may be slower than in individuals with early-onset Alzheimer's, but it can still significantly impact a person's quality of life.

Treating Alzheimer's Disease

Treating Alzheimer's is multifaceted, involving various methods to slow disease progression and manage symptoms. While there is no direct way to cure Alzheimer's disease, the below interventions target the symptoms:

  • Non-pharmacological Interventions: Non-pharmacological interventions are an important aspect of treatment, and lifestyle changes are key in improving the quality of life for those with Alzheimer's. These interventions include regular physical exercise, a healthy diet, and social engagement.
  • Disease-modifying Therapies: Disease-modifying therapies are designed to slow or halt Alzheimer's progression by targeting its underlying causes. Despite no approved disease-modifying drugs for Alzheimer's, clinical trials are exploring several treatments.
  • Immunotherapy: Immunotherapy, which involves using antibodies to remove beta-amyloid plaques from the brain, is a promising approach. Targeting inflammation in the brain has also shown potential in treating Alzheimer's.
  • Clinical Trials: Clinical trials are crucial in developing new treatments for Alzheimer's disease. These trials assess the safety and efficacy of potential drugs and therapies. For instance, the A4 Study tests the efficacy of an anti-amyloid drug in people at risk of Alzheimer's. The TRC-PAD study also tests the efficacy of several drugs in those with early-stage Alzheimer's.

Preventing Alzheimer's Disease

Preventing Alzheimer's Disease is a key research focus, as there is currently no cure for this debilitating illness. While there are no guaranteed ways to prevent Alzheimer's, several lifestyle factors can help reduce the risk of developing the disease.

Healthy Aging

Healthy aging involves maintaining physical, mental, and social well-being throughout the aging process.

Many lifestyle factors, including regular physical activity, a healthy diet, and good sleep hygiene, can promote healthy aging.

Regular exercise can help maintain physical function and reduce the risk of chronic conditions such as heart disease and diabetes.

A healthy diet, including fruits, vegetables, whole grains, lean protein, and healthy fats, can help prevent chronic diseases and maintain cognitive function.

Good sleep hygiene, including a consistent sleep schedule and a relaxing bedtime routine, can also help promote physical and mental health.

Additional Lifestyle Factors

It is important to recognize that certain lifestyle choices can significantly impact overall health and well-being. Avoiding smoking and limiting alcohol consumption are key components of a healthy lifestyle.

Smoking is a major risk factor for many chronic diseases, including cardiovascular disease, lung cancer, and Alzheimer's.

In addition, excessive alcohol consumption can also increase the risk of chronic diseases and cognitive decline.

Frequently Asked Questions About Alzheimer’s

What is Alzheimer's disease?

Alzheimer's is a progressive brain disorder affecting memory, thinking, and behavior.

What are the symptoms of Alzheimer's disease?

The symptoms of Alzheimer's disease include memory loss, confusion, difficulty completing familiar tasks, changes in mood or behavior, and difficulty communicating.

Can Alzheimer’s disease be cured?

Currently, there is no cure for Alzheimer's disease, but there are medications and therapies that can help manage the symptoms and improve the quality of life.

Is Alzheimer's the same as dementia?

Alzheimer's disease is a type of dementia, but there are many other types of dementia as well, such as vascular dementia and Lewy body dementia.

References

Alois Alzheimer – Irrenarzt mit Mikroskop

Alzheimer's genes: Are you at risk? - MayoClinic

Clinical Trials for Disease-Modifying Therapies in Alzheimer’s Disease: A Primer, Lessons

Environmental risk factors for dementia: a systematic review - BMC Geriatrics

How Is Alzheimer's Disease Diagnosed? - National Institute on Aging

How Is Alzheimer's Disease Treated? - National Institute on Aging

Disclaimer

The contents of this article are provided for informational purposes only and are not intended to substitute for professional medical advice, diagnosis, or treatment. It is always recommended to consult with a qualified healthcare provider before making any health-related changes or if you have any questions or concerns about your health. Anahana is not liable for any errors, omissions, or consequences that may occur from using the information provided.

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