Stages and course of the disease

Alzheimer’s disease gets worse slowly. Brain changes can happen years before signs and symptoms start. They include the buildup of plaques and tangles in the brain. Alzheimer's usually starts with mild symptoms. They get worse over time.

There are 3 basic stages of Alzheimer’s disease. People go through these stages at different speeds.

Preclinical Alzheimer’s disease

A person may not have symptoms in preclinical Alzheimer's disease. But changes that can’t be seen have started. These include changes in the brain, blood, and spinal fluid. Biomarkers can be found when these changes happen. Biomarkers can show if someone is at risk for a disease or has a disease. If they have a disease, a biomarker can show if it is getting worse.

Right now, there are not many ways to find biomarkers in Alzheimer’s disease. Someone can have a biomarker for Alzheimer’s, but never get it.

Mild cognitive impairment (MCI)

Mild cognitive impairment is also called MCI. It is when people with MCI show signs and symptoms of brain changes, like memory problems. These changes can be different for everyone.

Not everyone with MCI will develop Alzheimer’s. Sometimes, like when a medication causes brain changes, MCI can be reversed. People with MCI are more likely to get Alzheimer’s dementia than people who don’t have it.

Alzheimer’s dementia

The last stage is Alzheimer’s dementia. There are 3 stages: mild, moderate, and severe. People go through the stages at different speeds.

Mild Alzheimer’s dementia is the earliest stage. At this stage, people can do the things they usually do every day. But they may start to forget words, names, and where they put things. They may also have trouble with planning or organizing things. Family and friends may notice the person forgetting things.
Moderate Alzheimer’s dementia is usually the longest stage. It can last many years. At this stage, symptoms show more. People with Alzheimer’s may have a hard time doing things they do every day.

They may also forget basic information, like:
- Their address
- Their phone number
- What day it is
- Where they are
- How to dress
- How to control their bathroom habits
- Events that happened to them earlier in life
People can usually still remember major things. But they may confuse words. They may also become frustrated or mad easily. This can make them act differently than they usually do.

They may also have changes in mood. People with Alzheimer’s may:
- Not want to be in public
- Change their sleeping habits
- Wander and get lost
- Act differently. They may get suspicious, start believing things that aren’t real, or have urges they can’t control.
Severe Alzheimer’s dementia is the last stage of the disease. Symptoms become much more serious. At this stage, people may:
- Not know where they are
- Have trouble talking or listening
- Not be able to control how they move
- Change the way they act
People in this stage cannot always remember what just happened or where they are. They may not be able to walk, sit, or swallow. They might not be able to talk or understand a conversation.

People in this stage need constant help for everyday things like eating or getting dressed. People can easily get infections, such as pneumonia.

Alzheimer’s disease is a progressive condition. It usually starts off with mild symptoms which get worse over time. Changes in the brain may happen for many years before any symptoms are noticed. These include the buildup of amyloid plaques and tau tangles in the brain.

Alzheimer’s disease progresses differently in each person. There are 3 basic stages of Alzheimer’s disease.

Preclinical Alzheimer’s disease

No symptoms are obvious in preclinical Alzheimer’s disease, but changes in the brain, blood, and cerebrospinal fluid have already started. These changes may appear as Alzheimer’s biomarkers. Biomarkers are biological factors that can show if someone is at risk for a disease, has a disease, and whether or not a disease is progressing.

But right now, there are not that many ways to measure biomarkers in Alzheimer’s disease. Even if someone has a biomarker for Alzheimer’s, it does not necessarily mean they will progress to , and at present there is no way to stop them from doing so.other stages, and at present there is no way to stop them from doing so.

Mild cognitive impairment (MCI)

In mild cognitive impairment, or MCI, people with Alzheimer’s may show symptoms of mental decline such as memory problems. Not all changes in the brain are the same for people with MCI, and not all people with MCI develop Alzheimer’s.

In some cases, like when a medication causes mental changes, a person can get rid of MCI. But people who have MCI are more likely to develop Alzheimer’s dementia than people who don’t experience it.

Alzheimer’s dementia

The last stage of the disease, Alzheimer’s dementia, has three stages: mild, moderate, and severe. People move through these stages at different speeds.

Mild Alzheimer’s dementia is the earliest stage. At this stage, people may carry out their daily routines normally, but may start to forget words, names, and the location of objects. They may also have trouble with planning or organizing. Family and friends may begin to notice the person having difficulty with memory.
Moderate Alzheimer’s dementia is usually the longest stage and can last many years. At this stage, symptoms become more obvious. People with moderate Alzheimer’s may have a hard time doing everyday things.

They may also forget basic information, like:
- Their address and phone number
- What day it is
- Where they are
- How to dress
- How to control their bladder and bowels
- Events that happened to them earlier in life
People can usually remember major details, but they may confuse words, become easily frustrated or angry, or act out of character.

They may also have changes in mood. People with Alzheimer’s may:
- Start to withdraw from social situations
- Have changes in their sleeping habits
- Wander and become lost
- Experience changes in personality or behavior like becoming suspicious, delusional, or engaging in compulsive behaviors
Severe Alzheimer’s disease is the last stage of the disease, and symptoms become serious. At this stage, people:
- May not be aware of where they are
- May not be able to respond to their environment
- Have difficulty communicating or controlling their movement
- May have major changes in their personality because of memory and changes in thought processes
People in this stage are often not able to remember recent experiences, where they are, or how to walk, sit, or swallow. Communication becomes very hard. Constant help may be needed to help with daily activities and personal care. People in this stage are very vulnerable to infections, such as pneumonia.

Alzheimer’s disease is a progressive condition which typically starts off causing milder symptoms and then progresses over time to more severe symptoms. Even before symptoms are noticed, changes in the brain occur, such as the buildup of amyloid plaques and tau tangles. These changes can begin years before there are any symptoms.

How quickly Alzheimer’s disease progresses can vary from person to person, but there are 3 general stages once symptoms are noticed: preclinical Alzheimer’s disease, mild cognitive impairment (MCI), and Alzheimer’s dementia.

Alzheimer’s disease progresses differently in each person. There are 3 basic stages of Alzheimer’s disease:

Preclinical Alzheimer’s

In preclinical Alzheimer’s disease, no symptoms are present. Changes in the brain, blood, and cerebrospinal fluid have already begun. These changes are known as biomarkers because they can indicate that a person may have Alzheimer’s or is at a high risk of developing it. However, not all people with these changes develop MCI or dementia. Unfortunately, there are currently limited ways to measure these changes.

Mild cognitive impairment (MCI)

Mild cognitive impairment, or MCI, is characterized by symptoms of cognitive decline, such as memory problems. Not all people with MCI have the same cognitive changes, and not all people with MCI develop Alzheimer’s.

In some cases, like when a medication causes cognitive changes, MCI can be reversed. However, people who have MCI are more likely to develop Alzheimer’s dementia than people who don’t experience it.

Alzheimer’s dementia

Dementia due to Alzheimer’s is the last stage of the disease. Alzheimer’s dementia has 3 stages: mild Alzheimer’s disease, moderate Alzheimer’s disease, and severe Alzheimer’s disease. People progress through these stages at different rates.

Mild Alzheimer’s disease is the earliest stage. At this stage, people may carry out their daily routines normally, but may be starting to forget words, names, and the location of objects. They may also have trouble with planning or organizing. Family and friends may begin to notice the person experiencing difficulty with memory.
Moderate Alzheimer’s disease is usually the longest stage and can last many years. At this stage, symptoms have become more obvious and people may have difficulty performing everyday tasks. They can also forget basic information, like their address and phone number, what day it is, where they are, how to dress, how to control their bladder and bowels, and events that happened to them earlier in life.

Generally, people can still remember major details, but they can become easily frustrated or angry, confuse words, or act out of character. They may also become moody and start to withdraw from social situations, experience changes in their sleeping habits, wander and become lost, and undergo personality or behavior changes like becoming suspicious, delusional, or engage in compulsive behaviors.
Severe Alzheimer’s disease is the last stage of the disease, and symptoms become serious. At this stage, people may:
- Not be aware of or able to respond to their environment
- Have difficulty communicating
- Have trouble controlling their movement
- Experience memory loss and changes in thought processes, which can alter the personality of people in this stage
Constant assistance may be necessary to help with daily activities and personal care, since people in this stage are often not able to remember recent experiences, where they are, or how to walk, sit, or swallow. Communication becomes especially difficult. People in this stage are very vulnerable to infections, such as pneumonia.

NEXT: Signs and symptoms

References: 1. Stages of Alzheimer's. Alzheimer's Association. 2. Alzheimer's Facts 2021