Alzheimer’s disease is a progressive neurocognitive disorder that becomes worse over time. It involves a gradual loss of memory, as well as changes in behavior, thinking, and language skills.

Alzheimer’s disease is the most common form of dementia. It affects over 6 million people in the United States.

Although every person with Alzheimer’s experiences the disease differently, it is possible to divide its typical progression into a series of stages. However, identifying a stage is less important than ensuring a person has a good quality of life and that their needs are met.

In this article, find out roughly how people can expect Alzheimer’s disease to progress.

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Looking at Alzheimer’s disease in stages can provide a clearer idea of the possible changes that could affect someone following their diagnosis.

The stages can only be a rough guide, and experts have proposed many different “staging” systems over the years.

Some people think of the disease as having seven stages, while others refer to just three: early, middle, and late. The symptoms that occur and when they appear will vary from person to person.

In this article, we discuss Alzheimer’s disease in five stages:

  • Stage 1: preclinical Alzheimer’s disease
  • Stage 2: mild cognitive impairment due to Alzheimer’s disease
  • Stage 3: mild dementia due to Alzheimer’s disease
  • Stage 4: moderate dementia due to Alzheimer’s disease
  • Stage 5: severe dementia due to Alzheimer’s disease

Dementia describes a set of symptoms that affect memory, thinking, problem-solving, or language. In someone with dementia, these symptoms are severe enough to affect daily life.

Early-onset Alzheimer’s disease affects people who are under 65 years. Learn more here.

The changes that occur with Alzheimer’s may begin several years before diagnosis. This is known as the preclinical stage of Alzheimer’s disease.

During this stage, the individual will not have any noticeable symptoms, but imaging technologies can spot deposits of a protein called amyloid-beta.

In people with Alzheimer’s disease, this protein clumps together and forms plaques. These protein clumps may block cell-to-cell signaling and activate immune system cells that trigger inflammation and destroy disabled cells.

Scientists are working on ways to use biomarkers to identify Alzheimer’s at an earlier stage. That could help doctors make early diagnoses, which might lead to more effective treatment and better outcomes.

Genetic testing can help predict who might develop Alzheimer’s, and experts are looking into suitable ways to use these techniques.

Mild cognitive impairment (MCI) often occurs before the more severe decline of dementia. Some 12–18% of people aged 60 years or older have MCI, but not all will develop dementia. According to the National Institute on Aging, around 10–20% of people over the age of 65 with MCI will develop dementia within any 1-year period.

A person with MCI may notice subtle changes in their thinking and ability to remember things. They may have a sense of “brain fog” and find it hard to recollect recent events. These issues are not severe enough to cause problems with day-to-day life or usual activities, but loved ones may start to notice changes.

Many people become more forgetful with age or take longer to think of a word or remember a name. However, significant challenges with these tasks could be a sign of MCI.

Symptoms of MCI include:

  • forgetting appointments, conversations, or recent events more often than before
  • having difficulty making judgments
  • having difficulty carrying out tasks that involve several steps
  • getting confused about time, people, and places
  • neglecting self-care tasks, such as washing and eating
  • engaging in risky behavior
  • having depression
  • having a sense of “brain fog.

As of yet, there is no drug treatment for MCI, but some lifestyle choices may help manage it. Suggestions include:

  • following a daily routine
  • learning a new skill
  • spending time with friends and family
  • getting enough sleep
  • limiting alcohol consumption
  • seeking help for health conditions such as high blood pressure or depression

Get some tips on improving sleep.

The mild dementia stage is the point at which doctors typically diagnose Alzheimer’s disease. If people use a three-stage description of Alzheimer’s disease, this will be the early stage.

Problems with memory and thinking may become more noticeable to friends and family and also begin to affect daily life.

Symptoms of mild dementia due to Alzheimer’s disease include:

  • having difficulty remembering newly learned information
  • asking the same question repeatedly
  • having trouble solving problems and completing tasks
  • exhibiting reduced motivation to complete tasks
  • experiencing a lapse in judgment
  • becoming withdrawn or uncharacteristically irritable or angry
  • having difficulty finding the correct words to describe an object or idea
  • getting lost or misplacing items

When a person has moderate dementia due to Alzheimer’s disease, they become increasingly confused and forgetful. They may need help with daily tasks and with looking after themselves. This is the longest stage and often lasts around 2–4 years.

Symptoms of moderate dementia due to Alzheimer’s disease include:

  • losing track of the location and forgetting the way, even in familiar places
  • wandering in search of surroundings that feel more familiar
  • failing to recall the day of the week or the season
  • confusing family members and close friends or mistaking strangers for family
  • forgetting personal information, such as their address
  • repeating favorite memories or making up stories to fill memory gaps
  • needing help deciding what to wear for the weather or season
  • needing assistance with bathing and grooming
  • occasionally losing control of the bladder or bowel
  • becoming unduly suspicious of friends and family
  • seeing or hearing things that are not there
  • becoming restless or agitated
  • having physical outbursts, which may be aggressive

As Alzheimer’s progresses, a person may start to feel more restless toward evening and have difficulty sleeping. This is sometimes called sundowner’s syndrome.

During this stage, physical and mental functioning continue to decline.

If a person has severe dementia during the later stages of Alzheimer’s disease, they might:

  • have difficulty communicating and using language coherently
  • think they are at an earlier stage of life
  • be unable to recognize familiar faces, possibly due to remembering the person’s appearance at a younger age
  • need assistance with personal care, eating, dressing, and using the bathroom
  • have a higher risk of falls
  • spend more time in bed or a chair
  • have difficulty swallowing
  • lose bowel and bladder control
  • experience delusions and hallucinations
  • show aggression, possibly toward caregivers, due to fear or confusion

A person with severe Alzheimer’s disease has a high chance of dying from pneumonia. Pneumonia is a common cause of death in people with Alzheimer’s because the loss of ability to swallow means that food and beverages can enter the lungs and cause infection.

Other common causes of death among people with Alzheimer’s disease include dehydration, malnutrition, and other infections.

Not everyone experiences the stages of Alzheimer’s in the same way. How it progresses will vary between individuals.

A person may not have all the symptoms listed above, and symptoms may come and go. The stages can also overlap.

Medications can slow progression for a while, and may help with memory symptoms and other cognitive changes.

Factors that can affect disease progression include:

  • age, as progression may be faster in those whose symptoms develop before the age of 65
  • genetic factors
  • physical health, as symptoms can progress more quickly in people with a heart condition, diabetes, recurrent infections, and those who have had several strokes
  • if the person experiences delirium

Keeping active, being involved in activities, and getting regular exercise may help the individual stay active and involved for longer.

Other lifestyle changes that may help slow disease progression include:

  • maintaining a healthy diet
  • getting enough sleep
  • taking all prescribed medications correctly
  • quitting smoking
  • limiting or avoiding alcohol consumption
  • having regular health checkups

If a person with Alzheimer’s disease experiences a sudden change in their abilities or behavior, they could have another health problem or an infection. It is vital to seek advice from a doctor as soon as possible.

Caring for someone with Alzheimer’s disease can be challenging. Here, find some tips that may help.

Alzheimer’s disease is currently the sixth leading cause of death in the U.S. Around 1 in every 3 people aged 65 years and older will die from Alzheimer’s or another type of dementia. It kills more people than breast cancer and prostate cancer together.

Life expectancy for individuals with Alzheimer’s disease varies depending on many factors. The average life expectancy for a person with Alzheimer’s is 4–8 years after diagnosis, but people can live with Alzheimer’s for 20 years or more.

Black Americans may face additional challenges when seeking help for dementia. Here, find out more.

Alzheimer’s disease is a type of dementia and a neurocognitive disorder that happens when physical changes take place in the brain. It is not a sign of aging, but it is more likely to appear as people get older. Not everyone will develop dementia with age.

It is important to remember that a person with Alzheimer’s is still the same person, even if their behavior changes. Many people with Alzheimer’s experience frustration as they find it harder to do the things they used to do or struggle to remember things they feel they should know.

The more informed family members and loved ones are about Alzheimer’s and how it affects an individual, the better they will be able to provide help and support.

There is currently no way to prevent or cure Alzheimer’s, but ongoing research is looking at ways to detect the disease earlier and stop or reverse its progression.