What Is Alzheimer’s Disease?

Alzheimer’s disease is a neurodegenerative disorder that usually starts slowly and progressively worsens, leading to symptoms of dementia and eventually the loss of bodily functions. It is the most common cause of cognitive decline in adults, usually affecting people over the age of 65.

What causes Alzheimer’s Disease?

Alzheimer’s disease is poorly understood but is believed to be linked in part to genetics . The disease is characterized by the formation of plaques on the brain along with the development of twisted fibers (called neurofibrillary tangles) that block the flow of nutrients to brain cells, eventually killing them. A history of head injury, clinical depression , and high blood pressure are also linked to the disease.

What are the early signs of Alzheimer’s Disease?

Early symptoms of Alzheimer’s are often dismissed as “signs of aging” and can include short-term memory loss, loss of attentiveness, problems with planning, apathy, and depression. The signs become more noticeable when word fluency, fine motor skills, and short-term recall start to become affected.

What are the stages of Alzheimer’s Disease?

The course of Alzheimer’s can differ from one person to the next but tend to occur in the following 7 stages: Stage 1: Largely asymptomatic with changes only detected on a PET scan Stage 2: Very mild changes that don’t affect daily functioning Stage 3: Mild decline with more noticeable changes in memory and cognition Stage 4: Moderate decline that may affect a person’s ability to drive or manage their finances Stage 5: Moderately severe decline characterized by the loss of independence Stage 6: Severe declines that require assistive care Stage 7: Very severe decline marked by the lack of physical control and the need for around-the-clock care

How fast does Alzheimer’s develop?

It can vary. Some people may have mild cognitive problems for many years before Alzheimer’s is officially diagnosed. After the diagnosis, the progression of the disease—from stage 1 to stage 7—can range anywhere from four to eight years on average. Some people have lived for far longer.

Can Alzheimer’s be cured?

Not at present. However, there are treatments that may improve symptoms in some people. These include cholinesterase inhibitors like Aricept (donepezil), Razadyne (galantamine), and Exelon (rivastigmine) that may improve communication between nerve cells. Memantine (marketed under the brand name Namenda and others) may help reduce calcium build-up and the formation of plaques.

Can Alzheimer’s kill you?

Alzheimer’s disease is the sixth-leading cause of death in the United States. The progressive destruction of nerve connections in the brain can disrupt vital functions like swallowing. The majority of Alzheimer's deaths are due to aspiration pneumonia when food or liquid enters the windpipe and causes damage or infection in the lungs leading to pneumonia.

Alzheimer's Disease: Signs, Symptoms, and Complications

Memory loss and confusion are the two key symptoms of Alzheimer's disease. While anyone can have an episode of being unable to remember a name or where they put their keys, there is a significant difference between being absent-minded or preoccupied and having a true progressive memory problem such as Alzheimer's disease.

For example, these instances could be symptoms of Alzheimer's disease or another concerning cognitive issue:

You lose your keys. When they're found, you have no recollection of how they might have gotten there.
You always were a fantastic cook, but lately even making coffee seems more difficult. You wonder who has been messing around with your coffeemaker.
You're great at covering for yourself. For example, when someone asks you a question to which you don't know the answer, you turn the question around by saying with a chuckle, "I'm not sure. What do you think?"
You've had a hard time recently balancing your checkbook, even though that's always been your job.

If these symptoms paint a picture of you or someone you love, seek an evaluation from a physician, geriatrician, or psychologist.

Frequent Symptoms

The Alzheimer's Association has identified 10 warning signs of Alzheimer's disease:

Memory changes
Withdrawal from usual activities
Disorientation to time and place
Visual-spatial difficulties
Decrease in written or verbal communication ability
Challenges in problem-solving and planning
Personality and mood changes
Misplacing items frequently
Decline in judgment
Difficulty performing familiar tasks

The Four As

Alzheimer's disease has also been described using four words that begin with A:

Amnesia: Memory loss
Aphasia: Impaired communication
Apraxia: Physical functioning (motor skills)
Agnosia: Difficulty understanding information from the senses, such as vision or smell

Understanding the 4 As of Alzheimer's

By Stage

While Alzheimer's disease has been described as having seven stages, the symptoms of Alzheimer's can be collapsed into three broad stages: early, middle, and late.

Remember that symptoms can overlap and may vary in each person with Alzheimer's.

Early (Mild)-Stage Symptoms

Difficulty with tasks such as balancing a checkbook or making dinner
Difficulty learning new tasks
Slower reaction time when driving or making decisions
Occasional difficulty finding words
Short-term memory impairment
Increased irritability, anxiety, or depression
Often an awareness of these changes

In early-stage Alzheimer's, individuals may still function quite well overall. Although they may be aware of the increasing difficulty with certain tasks, they are also often quite skilled at hiding this from others by deflecting questions, changing the topic, or relying on their family or loved ones to make decisions or answer questions.

Some persons also begin to withdraw, perhaps due to their uncertainty over their ability to cope with decisions or social interaction.

In early-stage Alzheimer's, long-term memory typically remains intact.

Middle (Moderate)-Stage Symptoms

Significant personality changes, such as being argumentative, impulsive, angry
Resistant to, or combative with, physical care, even (sometimes especially) when provided by a loved one
Short-term and long-term memory loss
Increased difficulty in communicating with others
A "love-hate" relationship with their caregivers; for example, extreme dependence on a spouse or adult child who they also are very unkind to
Potential for wandering away from home
Very poor judgment and decisions
Possible incontinence

Often, one's physical abilities—such as their ability to walk around—still remain intact in this stage.

Mid-stage Alzheimer's is often the most difficult stage. While some individuals remain "pleasantly confused" throughout the entire disease, many display inappropriate behaviors and emotions.

They may be quite restless and become paranoid, have hallucinations, or refuse to let you help them with a bath or getting dressed. They may get up several times in the night, and rummage through the same drawers repeatedly.

This middle stage of Alzheimer's can be very taxing for the primary caregiver, and this is often when in-home help is hired or the person is placed in a facility, such as an assisted living or a nursing home.

Late (Severe)-Stage Symptoms

Decreased ability to interact with others
Diminished ability to recognize people
Physical decline, such as inability to walk or talk
Difficulty with eating, even with assistance
Apparent withdrawal from surroundings
Incontinence

In this final stage of Alzheimer's, people often are quite immobile and spend much of their time in bed or a wheelchair. They are no longer able to respond much to others, although you may occasionally receive a smile or hear some attempts at language.

Symptoms of stage 3 Alzheimer's Dementia — Verywell / JR Bee

The behavior challenges of mid-stage Alzheimer's are replaced with what looks like complete withdrawal. However, these individuals can still benefit from gentle conversation, holding their hand, giving them a hug, visual stimulation such as colors and pictures, and especially hearing music. Individuals with late-stage Alzheimer's become more prone to illnesses as the body loses strength. Often, infections like pneumonia eventually cause their death.

Complications/Sub-Group Indications

While Alzheimer's disease most often presents symptoms after age 65, early-onset Alzheimer's disease is seen in about 5% of cases. Early onset dementia often affects people as young as those in their 40s and 50s.

The symptoms are similar and are most apparent when someone is performing a job or task. Because the onset is gradual, the symptoms might be dismissed as being due to stress or depression. However, early detection of cognitive impairment can help determine the cause and lead to earlier treatment.

Familial Alzheimer's disease often has early onset. This type is linked to specific genes and affects at least two generations. It occurs in less than 3% of all cases of Alzheimer's disease.

Complications of Alzheimer's disease include an increased risk of falling and a higher risk of hip fractures from falls. Remaining as active as possible, for as long as possible, may help delay some of the physical changes in motor functioning that develop in Alzheimer's.

As Alzheimer's can cause someone to engage in unsafe behaviors such as wandering, losing concentration when driving, and leaving a stove burner on, it's also important to be aware of other injuries that may result.

Bladder and bowel problems may also develop as the person doesn't recognize urges, has limited mobility, or is confused as to where the bathroom is. There can also be difficulty in eating, drinking, and swallowing, leading to aspiration pneumonia, choking, malnutrition, and dehydration.

When to See a Doctor

If you see yourself or your loved one described in these symptoms, contact your physician to arrange for an evaluation. Diagnosing Alzheimer's disease involves several tests to rule out other conditions and is an important first step in treatment and management of the disease.

Know, though, that not all problems with cognition (the ability to think and remember) are due to Alzheimer's disease or other forms of dementia. This is one of many reasons why it's important to see your physician if you're experiencing these symptoms.

A Word From Verywell

Affecting more than 5 million people in the United States alone, Alzheimer's disease is far from uncommon. However, because Alzheimer's disease affects the mind and many other conditions affect the body, there can be a greater fear and stigma about the disease. Unfortunately, this can cause people to hide and ignore symptoms, delay treatment, or simply isolate themselves. Hold on to the knowledge that there is no blame or shame in an Alzheimer's diagnosis. Instead, by seeking support, you can gain strength, knowledge, and hope while living with Alzheimer's disease.

Frequently Asked Questions

What Is Alzheimer’s Disease?

Alzheimer’s disease is a neurodegenerative disorder that usually starts slowly and progressively worsens, leading to symptoms of dementia and eventually the loss of bodily functions. It is the most common cause of cognitive decline in adults, usually affecting people over the age of 65.
What causes Alzheimer’s Disease?

Alzheimer’s disease is poorly understood but is believed to be linked in part to genetics. The disease is characterized by the formation of plaques on the brain along with the development of twisted fibers (called neurofibrillary tangles) that block the flow of nutrients to brain cells, eventually killing them. A history of head injury, clinical depression, and high blood pressure are also linked to the disease.
What are the early signs of Alzheimer’s Disease?

Early symptoms of Alzheimer’s are often dismissed as “signs of aging” and can include short-term memory loss, loss of attentiveness, problems with planning, apathy, and depression. The signs become more noticeable when word fluency, fine motor skills, and short-term recall start to become affected.
What are the stages of Alzheimer’s Disease?
The course of Alzheimer’s can differ from one person to the next but tend to occur in the following 7 stages:
- Stage 1: Largely asymptomatic with changes only detected on a PET scan
- Stage 2: Very mild changes that don’t affect daily functioning
- Stage 3: Mild decline with more noticeable changes in memory and cognition
- Stage 4: Moderate decline that may affect a person’s ability to drive or manage their finances
- Stage 5: Moderately severe decline characterized by the loss of independence
- Stage 6: Severe declines that require assistive care
- Stage 7: Very severe decline marked by the lack of physical control and the need for around-the-clock care
Learn More: What to Know About Telehealth for Alzheimer’s Disease
How fast does Alzheimer’s develop?

It can vary. Some people may have mild cognitive problems for many years before Alzheimer’s is officially diagnosed. After the diagnosis, the progression of the disease—from stage 1 to stage 7—can range anywhere from four to eight years on average. Some people have lived for far longer.
Can Alzheimer’s be cured?

Not at present. However, there are treatments that may improve symptoms in some people. These include cholinesterase inhibitors like Aricept (donepezil), Razadyne (galantamine), and Exelon (rivastigmine) that may improve communication between nerve cells. Memantine (marketed under the brand name Namenda and others) may help reduce calcium build-up and the formation of plaques.

Learn More: How Alzheimer's Disease Is Treated
Can Alzheimer’s kill you?

Alzheimer’s disease is the sixth-leading cause of death in the United States. The progressive destruction of nerve connections in the brain can disrupt vital functions like swallowing. The majority of Alzheimer's deaths are due to aspiration pneumonia when food or liquid enters the windpipe and causes damage or infection in the lungs leading to pneumonia.