What Causes Alzheimer’s In The Brain

Medications For Cognitive Symptoms

No disease-modifying drugs are available for Alzheimers disease, but some options may reduce the symptoms and help improve quality of life.

Drugs called cholinesterase inhibitors can ease cognitive symptoms, including memory loss, confusion, altered thought processes, and judgment problems. They improve neural communication across the brain and slow the progress of these symptoms.

Three common drugs with Food and Drug Administration approval to treat these symptoms of Alzheimers disease are:

• donepezil , to treat all stages
• galantamine , to treat mild-to-moderate stages
• rivastigmine , to treat mild-to-moderate stages

Another drug, called memantine , has approval to treat moderate-to-severe Alzheimers disease. A combination of memantine and donepezil is also available.

Genetic Testing And Alzheimers Disease

Testing can show whether you have a version of a gene that increases your risk of Alzheimers. Testing can also uncover the rare cases when an inherited genetic change, or mutation, causes Alzheimers.

At OHSU, we generally do not recommend routine genetic testing for Alzheimers because:

• Many factors can lead to the disease.
• Most people who develop Alzheimers do not have a related genetic variant.
• Most people who have a variant do not develop the disease.

Talk with your primary care doctor or to a medical geneticist to learn more or to better understand your risk if youve taken a test on your own.

Genetic testing can show whether you carry an inherited gene mutation that causes early-onset Alzheimers. In some cases, we may recommend testing to confirm a diagnosis in someone who has signs or symptoms of early-onset Alzheimers.

Some family members, after careful discussion with a genetic counselor, may also want testing to find out whether they carry the mutation.

At-home tests from DNA analysis companies can give consumers access to limited genetic testing, without guidance from a genetic counselor. An at-home test can detect variants that increase the risk of late-onset Alzheimers disease.

What Is Alzheimer’s Disease

Alzheimers disease is a brain disorder that cannot be stopped or reversed. The disease severely affects memory, thinking, learning and organizing skills and eventually affects a persons ability to carry out simple daily activities. Alzheimers disease is not a normal part of the aging process.

Alzheimers is a disease whose symptoms worsen over time. In fact, scientists believe the disease process may go on for 10 years or longer before the first symptoms of Alzheimers disease appear.

When memory problems do begin to be noticeable, they are often identified as mild cognitive impairment . At this stage, intellectual function is affected but the ability to function and live independently remain intact as the brain compensates for disease-related changes.

In some people, MCI can hold steady at this stage. However, people with MCI are at high risk for progressing to dementia. Alzheimers disease is the most common form of dementia. With dementia, in contrast to MCI, daily function is affected.

As dementia due to Alzheimers disease progresses to late stages, affected individuals cannot carry on a conversation, recognize family and friends, or care for themselves.

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Genetics And Family History

Genetics play a role in influencing ones likelihood of developing Alzheimers, but there is as yet no known definitive genetic cause.

Alzheimers is broadly defined as either late-onset or early-onset, with each affected by different genetic components.

Late-onset Alzheimers, which tends to affect people from their mid-60s on, has no known specific genetic cause but does associate with a variant of the apolipoprotein E gene as a possible risk factor. Although APOE is thought to increase a persons risk of developing Alzheimers, inheriting it does not mean a person will develop the condition.

Accounting for fewer than 10% of all cases, early-onset Alzheimers tends to occur in individuals between their mid-30s and mid-60s. Some cases appear to stem from inherited changes in one of three genes: APP, presenilin 1 , and presenilin 2 . The abnormal proteins produced by mutations in these genes all affect the breakdown of the APP protein, which can lead to amyloid plaques.

What Can Lead To Alzheimer’s Disease

There are a few things that may make people more likely to get Alzheimerâs. So far, research has linked the disease with:

• Age. Your risk for Alzheimer’s goes up as you get older. For most people, it starts going up after age 65.
• Gender. Women get the disease more often than men.
• Family history. People who have a parent or sibling with Alzheimerâs are more likely to get it themselves.
• Down syndrome. Itâs not clear why, but people with this disorder often get Alzheimer’s disease in their 30s and 40s.
• Head injury. Some studies have shown a link between Alzheimer’s disease and a major head injury.
• Other factors. High cholesterol levels and high blood pressure may also raise your risk.

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How Alzheimers Disease Progresses

An individuals abilities deteriorate over time, although the progression varies from person to person.

As Alzheimers disease affects different areas of the brain, specific functions or abilities are lost. Short-term memory is often the first to be affected, but as the disease progresses, long-term memory is also lost. The disease also affects many of the brains other functions and consequently language, attention, judgement and many other aspects of behaviour are affected.

Some abilities remain, although these lessen as Alzheimers disease progresses. People living with advancing dementia may keep their senses of touch and hearing, and also respond to emotion even in the advanced stages of the condition.

At the end stages of Alzheimers disease many people become immobile and dependent, requiring extensive care.

What Causes Alzheimer Disease

Lots of research is being done to find out more about the causes of Alzheimer disease. There is no one reason why people get it. Older people are more likely to get it, and the risk increases the older the person gets. In other words, an 85-year-old is more likely to get it than a 65-year-old. And women are more likely to get it than men.

Researchers also think genes handed down from family members can make a person more likely to get Alzheimer disease. But that doesn’t mean everyone related to someone who has it will get the disease. Other things may make it more likely that someone will get the disease, such as high blood pressure, high cholesterol, Down syndrome, or having a head injury.

On the positive side, researchers believe exercise, a healthy diet, and taking steps to keep your mind active may help delay the start of Alzheimer disease.

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How Is Alzheimers Diagnosed And Treated

Doctors may ask questions about health, conduct cognitive tests, and carry out standard medical tests to determine whether to diagnose a person with Alzheimers disease. If a doctor thinks a person may have Alzheimers, they may refer the person to a specialist, such as a neurologist, for further assessment. Specialists may conduct additional tests, such as brain scans or lab tests of spinal fluid, to help make a diagnosis. These tests measure signs of the disease, such as changes in brain size or levels of certain proteins.

There is currently no cure for Alzheimers, though there are several medicines approved by the U.S. Food and Drug Administration that can help manage some symptoms of the disease along with coping strategies to manage behavioral symptoms. In 2021, FDA provided accelerated approval for a new medication, aducanumab, that targets the protein beta-amyloid, which accumulates abnormally in the brains of people with Alzheimers. The new medication helps to reduce amyloid deposits, but has not yet been shown to affect clinical symptoms or outcomes, such as progression of cognitive decline or dementia.

Most medicines work best for people in the early or middle stages of Alzheimers. Researchers are exploring other drug therapies and nondrug interventions to delay or prevent the disease as well as treat its symptoms.

Who Has Alzheimers Disease

• In 2020, as many as 5.8 million Americans were living with Alzheimers disease.1
• Younger people may get Alzheimers disease, but it is less common.
• The number of people living with the disease doubles every 5 years beyond age 65.
• This number is projected to nearly triple to 14 million people by 2060.1
• Symptoms of the disease can first appear after age 60, and the risk increases with age.

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How Does Alzheimers Disease Affect The Brain

The brain typically shrinks to some degree in healthy aging but, surprisingly, does not lose neurons in large numbers. In Alzheimers disease, however, damage is widespread, as many neurons stop functioning, lose connections with other neurons, and die. Alzheimers disrupts processes vital to neurons and their networks, including communication, metabolism, and repair.

At first, Alzheimers disease typically destroys neurons and their connections in parts of the brain involved in memory, including the entorhinal cortex and hippocampus. It later affects areas in the cerebral cortex responsible for language, reasoning, and social behavior. Eventually, many other areas of the brain are damaged. Over time, a person with Alzheimers gradually loses his or her ability to live and function independently. Ultimately, the disease is fatal.

What Is Alzheimers Disease

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• More Resources on Alzheimers

Alzheimers disease is a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. People with Alzheimers also experience changes in behavior and personality.

More than 6 million Americans, many of them age 65 and older, are estimated to have Alzheimers disease. Thats more individuals living with Alzheimers disease than the population of a large American city. Many more people experience Alzheimer’s in their lives as family members and friends of those with the disease.

The symptoms of Alzheimers disease changes in thinking, remembering, reasoning, and behavior are known as dementia. Thats why Alzheimers is sometimes referred to as dementia. Other diseases and conditions can also cause dementia, with Alzheimers being the most common cause of dementia in older adults.

Alzheimers disease is not a normal part of aging. Its the result of complex changes in the brain that start years before symptoms appear and lead to the loss of brain cells and their connections.

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How Do People Know They Have It

The first sign of Alzheimer disease is an ongoing pattern of forgetting things. This starts to affect a person’s daily life. He or she may forget where the grocery store is or the names of family and friends. This stage may last for some time or get worse quickly, causing more severe memory loss and forgetfulness.

Can You Prevent Alzheimers Disease

There is no sure way to prevent Alzheimers disease. However, you can reduce the risk of Alzheimers disease by caring for your health:

• your heart whats good for your heart is good for your brain so stick to a healthy diet and dont smoke
• your body regular physical activity increases blood flow to the brain so maintain an active lifestyle
• your mind an active mind helps build brain cells and strengthens their connections so socialise, do things such as puzzles and crosswords, and learn new things, such as a language

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What Is Alzheimer Disease

Alzheimer disease, which affects some older people, is different from everyday forgetting. It is a condition that permanently affects the brain. Over time, the disease makes it harder to remember even basic stuff, like how to tie a shoe.

Eventually, the person may have trouble remembering the names and faces of family members or even who he or she is. This can be very sad for the person and his or her family.

It’s important to know that Alzheimer disease does not affect kids. It usually affects people over 65 years of age. Researchers have found medicines that seem to slow the disease down. And there’s hope that someday there will be a cure.

What Happens To The Brain With Alzheimers

During Alzheimers progression, several cellular and molecular changes occur in the brain that can be seen microscopically in an autopsy after the patients death. Researchers are still trying to determine which changes cause Alzheimers and which changes are the results of the disease. The most prominent effects on the brain 3include the formation of beta-amyloid plaques, neurofibrillary tangles, loss of neuronal connections, and cell death.

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Stages Of Alzheimers Disease

Some features of Alzheimers disease are commonly classified into three stages, or phases. Not all these features will be present in every person, and they might occur at different stages.

Mild Alzheimers disease

Sometimes this stage is only apparent in hindsight. The onset of Alzheimers disease is usually gradual and it is often impossible to identify exactly when it began.

Someone might:

• have difficulty shopping or preparing meals.

Moderate Alzheimers disease

At this stage, the impacts of the condition are more apparent and prevalent. A person may experience significant challenges to their independence and require daily support.

Someone might:

• be forgetful of current and recent events, although generally remember the distant past, even if details may be forgotten or confused
• often be confused regarding time and place
• become lost more easily
• forget the names of family or friends, or confuse family members
• forget saucepans or kettles left heating on the stove
• be less able to perform simple calculations
• show poor judgement and make poor decisions
• see or hear things that are not there or become suspicious of others

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 Causes Alzheimers

The causes of Alzheimers disease are not yet fully understood, but probably include a combination of:

• Age-related changes in the brain, like shrinking, inflammation, blood vessel damage, and breakdown of energy within cells, which may harm neurons and affect other brain cells.
• Changes or differences in genes, which may be passed down by a family member. Both types of Alzheimer’s the very rare early-onset type occurring between age 30 and mid-60s, and the most common late-onset type occurring after a persons mid-60s can be related to a persons genes in some way. Many people with Down syndrome, a genetic condition, will develop Alzheimers as they age and may begin to show symptoms in their 40s.
• Health, environmental, and lifestyle factors that may play a role, such as exposure to pollutants, heart disease, stroke, high blood pressure, diabetes, and obesity.

Watch this video to see how Alzheimers disease changes the brain.

Key Points About Early

• Alzheimer disease commonly affects older people, but early-onset Alzheimer disease can affect people in their 30s or 40s.

• It affects memory, thinking, and behavior.

• Although there is no known cure, early diagnosis and treatment can lead to better quality of life.

• Stay healthy with a good diet and regular exercise.

• Avoid alcohol and other substances that may affect memory, thinking, and behavior.

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How Is Alzheimer’s Disease Diagnosed And Evaluated

No single test can determine whether a person has Alzheimer’s disease. A diagnosis is made by determining the presence of certain symptoms and ruling out other causes of dementia. This involves a careful medical evaluation, including a thorough medical history, mental status testing, a physical and neurological exam, blood tests and brain imaging exams, including:

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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Alcohol Or Illicit Drugs

Drinking alcohol or using illicit drugs can impair your memory, both in the short term and long term. From blackouts to an increased risk of dementia years later, these substances can significantly harm your memory, among many other things. Too much alcohol can also cause Wernicke-Korsakoff syndrome, which if treated immediately, may be able to be partially reversed in some people.

What Are The Symptoms Of Alzheimer’s Disease

The hallmark symptom of Alzheimer’s disease is loss of memory, which results from early degeneration and death of neurons in the hippocampus, a structure crucially involved in memory formation. The hippocampus is also important for spatial navigation, as is the entorhinal cortex, which is the typical starting point for cell death in Alzheimer’s disease.

Consistent with damage in these regions, people with Alzheimer’s patients can be disoriented, confused and have memory problems. Subsequently, symptoms can progress to include motor difficulties and impairments in executive planning and decision making. Importantly, the timecourse of these changes is characteristic of the spread of the disease seen in Alzheimer’s patients.

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