What Are the 3 Stages of Alzheimer’s Dementia?

From Mild Cognitive Impairment to Alzheimer’s Dementia

Alzheimer’s disease (AD) is the most common dementia type in people over 65. It's a progressive disease that impairs your cognitive ability and interferes with your ability to function. Common symptoms include:

  • Memory loss
  • Inability to problem-solve
  • Lack of judgment

While no two cases of Alzheimer's follow the same path, the progression of AD generally falls into three primary stages based on signs and symptoms.

This article looks at the three stages of Alzheimer's disease recognized by the National Institutes of Health (NIH), how they interfere with activities of daily living (ADL), and what stage 3 of Alzheimer's is like depending on the severity of dementia.

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

Stages and Activities of Daily Living

Alzheimer's staging involves activities of daily living and how much the disease interferes with them.

ADLs are the routines you go through every day, such as:

  • Eating
  • Dressing
  • Bathing/showering
  • Hygiene and grooming (e.g., brushing your teeth and hair)

As AD progresses through the stages, ADLs become more and more difficult.

Differing Definitions

There are multiple definitions of Different healthcare practitioners and organizations use different criteria for Alzheimer's stages. Some may identify five or seven different stages. The NIH recognizes three stages, with the final stage divided into three severity levels.

Stage 1: Preclinical Alzheimer's

In stage 1, your brain may have begun to change. For example, imaging studies may reveal changes in nerve cells and the build-up of amyloid-ß (beta), an abnormal protein that forms masses in the brain called plaques.

During this stage, you may have no symptoms or symptoms that are too mild to notice. Your ADLs remain unimpaired. Stage 1 can last for many years or even decades.

This stage is most often diagnosed in research studies, not in clinical practice.

Stage 2: Mild Cognitive Impairment

Stage 2 is called mild cognitive impairment (MCI). It's defined as:

  • More memory problems than are normal for your age
  • Symptoms still don't have a significant impact on ADL

Symptoms of MCI are usually mild and involve problems in cognition—brain-based abilities required to learn, form and retrieve memories, problem-solve, and pay attention.

The first symptoms of Alzheimer’s vary from person to person. You may experience:

  • Memory loss
  • Difficulty recalling known words
  • Vision problems
  • Impaired reasoning or judgment 

These problems may lead to behaviors such as:

  • Wandering and getting lost
  • Forgetting to pay bills
  • Missing appointments
  • Losing things
  • Repeatedly asking the same questions

Most people are diagnosed during this stage. Symptoms necessary for a diagnosis of MCI include:

  • Concern about a change in cognition (compared to your previous level of function)
  • Impairment of one or more cognitive functions, such as problem-solving or memory, that's greater than expected for your age and education level
  • Ability to perform ADLs, although they may have started becoming more difficult

Stage 3: Alzheimer’s Dementia

Not everyone with MCI will go on to develop the third and most severe stage of Alzheimer’s disease—Alzheimer’s dementia. This stage involves problems with the brain, including:

  • Loss of normal neuron (brain cell) connections
  • Death of nerve cells due to amyloid plaques and other factors

Alzheimer's dementia is classified by its severity.

Mild Dementia

In mild Alzheimer’s dementia, symptoms are severe enough to interfere with ADLs. They include:

  • Worsening memory loss, when compared to MCI
  • Poor judgment
  • Making bad decisions
  • Declines in motivation and spontaneity
  • Taking longer than normal to perform daily tasks

This leads to problems and behaviors such as:

  • Repeating the same questions or stories over and over
  • Having difficulty balancing the checkbook, managing money, and/or paying bills
  • Getting lost in familiar places
  • Wandering away from home
  • Losing things and finding them in very odd places (such as the cell phone in the refrigerator)

Mood and Personality Changes

During mild dementia, other people may start noticing changes in mood and personality, especially increasing anxiety and aggression.

Moderate Dementia

The hallmark sign of moderate Alzheimer’s dementia is that supervision becomes increasingly necessary. Symptoms interfere more with ADLs and involve:

  • Worsening memory loss and confusion
  • An inability to learn anything new
  • Worsening language problems (reading, writing, remembering words)
  • Trouble calculating numbers
  • Problems thinking logically
  • Heightened problems with focus
  • Declining attention span
  • Trouble organizing thoughts
  • An inability to cope with stress or new situations

In addition, the following symptoms are notable in the moderate Alzheimer's dementia stage:

  • Difficulty with multi-step tasks (such as following a recipe)
  • Trouble recognizing people (including close friends and family members)
  • Symptoms of paranoia (severe fear), delusions (believing things that are untrue), and hallucinations (seeing things that aren't there)
  • Angry outbursts
  • Impulsive behavior
  • Inappropriate language
  • Restlessness, anxiety, and agitation
  • Wandering/getting lost in familiar places (such as a person’s own neighborhood)
  • Impulsive behavior such as undressing at inappropriate times or places or using vulgar language
  • Inappropriate outbursts of anger
  • Repetitive movements or muscle twitches

Severe Dementia

People with severe Alzheimer’s dementia are completely dependent on others for care and require 24/7 supervision. Symptoms from the moderate stage grow worse.

Additional symptoms may be:

  • Trouble eating and swallowing
  • Weight loss
  • Inability to communicate
  • Skin infections
  • Loss of bowel and bladder control
  • Constant sleeping or being bedridden
  • Inability to walk
  • Seizures

Eventually, the body shuts down and death occurs.

New Understanding

Alzheimer's didn't used to be diagnosable until memory loss and other symptoms became apparent. Now, studies have found changes in the brain may start 20 or even 30 years before the first symptoms begin.

With the early stages better recognized, people are getting an earlier diagnosis. That means they can start treatments and preventive measures that may stave off symptoms and the progression to later stages.

The NIH has funded research aimed at even earlier detection of preclinical Alzheimer's disease. 


Alzheimer's disease involves three stages: preclinical disease, mild cognitive impairment, and dementia. The dementia stage is divided into mild, moderate, and severe categories.

As the disease advances, symptoms of memory loss and other cognitive declines become more apparent and more likely to impair activities of daily living. The people who progress to the final stage need around-the-clock care and supervision.

With advances in diagnosis, treatment, and prevention, fewer people advance to the dementia stage.

A Word From Verywell

When you or a loved one is diagnosed with Alzheimer's disease, it can be frightening. It's normal to go through a grieving process as you adjust to living with the disease.

Rest assured, though, that treatments are always improving. Fewer people are now progressing out of the earlier stages and into dementia. And future research is likely to improve the situation even more.

1 Source
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institutes of Health, National Institute on Aging. Alzheimer's disease fact sheet.

Additional Reading

By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.