The Three Stages of Alzheimer's Disease

Medically Reviewed By William C. Lloyd III, MD, FACS
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A diagnosis of Alzheimer’s disease might come after a person develops a habit of losing the house keys or getting lost. But changes in the hippocampus, the part of the brain essential to forming memories, begin years before any symptoms appear. Once they emerge, the incurable disease advances through three stages.

Each person may progress through Alzheimer’s stages at different speeds or experience symptoms in different ways. By understanding its typical course, you can be prepared for the road ahead and focus on living well with the disease.

Early Stage: Mild Alzheimer’s Disease

People are often diagnosed at this stage, as memory loss and other thinking problems become apparent. The person may notice his or her own memory lapses, such as forgetting familiar words. Or family and friends may notice changes, such as trouble handling money or paying bills.

Common difficulties in this stage include:

  • Forgetting material that one has just read
  • Forgetting common words or names
  • Losing or misplacing valuable objects
  • Repeating questions
  • Taking longer to complete normal daily tasks
  • Trouble planning or organizing
  • Wandering and getting lost

Middle Stage: Moderate Alzheimer’s Disease

In this stage, damage occurs in areas of the brain controlling language, reasoning, sensory processing, and conscious thought. This stage can last for many years while a person gradually loses abilities that allow him or her to live independently.

During this stage, other people may begin to notice symptoms. They may include:

  • Changes in sleep patterns, such as sleeping during the day and becoming restless at night
  • Confusion about where they are or what day it is
  • Forgetting past events or personal history
  • Forgetting personal details, such as home address or telephone number
  • Increased risk of wandering and getting lost
  • Moodiness or withdrawal, especially in social or mentally challenging situations
  • Needing help choosing appropriate clothing for the season or occasion
  • Not recognizing family and friends
  • Personality and behavior changes, such as paranoia and delusions, impulsive behavior, or compulsive, repetitive behavior like hand-wringing

Late Stage: Severe Alzheimer’s Disease

Basic abilities diminish in the final stage. A person can no longer carry on a conversation or respond to his or her environment. He or she will gradually lose the ability to walk.

Special concerns for a person with late stage Alzheimer’s include:

  • Inability to communicate pain
  • Difficulty eating and drinking
  • Increasing personality changes
  • Vulnerability to infections, especially pneumonia

A person will likely need around-the-clock help to address extensive care needs. But loved ones can provide care by spending time with a person in the last stage of the disease.

Diagnosing Alzheimer’s Disease

Researchers are looking for ways to find Alzheimer’s in its earliest stage, before symptoms appear. Studies suggest early detection through brain scans or blood and spinal fluid tests may be possible, but more research is needed before these tests become common practice.

Until there is a single diagnostic test, doctors use a combination of methods and tools to determine if a person has “possible” or “probable” Alzheimer’s dementia. A “possible” diagnosis is given if there may be another cause for the dementia. If no other cause can be found, the diagnosis is “probable” Alzheimer’s dementia.

To make a diagnosis, doctors may:

  • Ask for a medical history, including past medical problems, changes in health or abilities, and medical conditions affecting other family members, especially Alzheimer’s disease and other dementias
  • Carry out a physical exam with standard diagnostic tests, such as taking blood and urine samples
  • Conduct tests of memory, problem solving, attention, counting, and language
  • Perform brain scans, such as CT (computed tomography), MRI (magnetic resonance imaging), or PET (positron emission tomography)

In some cases, a brain autopsy after death can be performed to provide a positive diagnosis.

When to Have a Dialogue With Your Doctor

If you or a loved one are concerned about Alzheimer’s, talk with your doctor. Symptoms of dementia are linked to many other conditions besides Alzheimer’s, including anemia, diabetes, and heart and lung problems. Sharing key details with your doctor can help him or her determine the cause and best course of treatment.

If the diagnosis is Alzheimer’s, your doctor will do more than offer treatment. He or she can be a valuable resource for answering questions and finding support services for you.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Aug 23
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Alzheimer’s Disease Fact Sheet. National Institute on Aging.
  2. Alzheimer’s Disease Treatments. National Institutes of Health.
  3. Late-Stage Caregiving. Alzheimer’s Association.
  4. Stages of Alzheimer’s. Alzheimer’s Association.
  5. Tests for Alzheimer’s Disease and Dementia. Alzheimer’s Association.