The 3 Stages of Alzheimer’s Disease

The three stages of Alzheimer's disease refer to the period of time beginning when symptoms become apparent. For many years, this was considered to be the start of the disease.

stages of Alzheimer's

People in the mild stage of Alzheimer’s still are able to have coherent conversations, but they may have trouble finding the right words or remembering names.

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Because Alzheimer’s disease continues to get worse over time, it’s often thought of as unfolding in stages. This can be helpful, but it’s important to understand that when it comes to the stages of Alzheimer’s, the symptoms and rate of progression can vary from person to person.

There are different systems for staging Alzheimer’s disease. Many experts categorize it as mild (early-stage), moderate (middle-stage), and severe (late-stage). These stages refer to the period of time beginning when symptoms become apparent. For many years, this was considered to be the start of the disease.

It is now known that the disease process actually begins before the diagnosis can be made. To reflect the deeper understanding of Alzheimer’s disease and to prepare for future advancements in diagnosis and treatment, the National Institute on Aging and the Alzheimer’s Association describe three distinct stages of Alzheimer’s disease. These are:

  • Preclinical: In this stage, brain changes have begun but symptoms are not evident. People in this stage have “biomarkers” of Alzheimer’s disease, such as buildup of beta-amyloid in the brain, which can be detected with new, experimental tests. Currently, this stage is used only in the context of a research study, and the diagnostic parameters are still being evaluated. It is not yet clear what proportion of people who have the biomarkers end up with clinical symptoms of the disease, and over what period of time.
  • MCI due to Alzheimer’s: The MCI stage is marked by noticeable memory problems that can be measured. But they don’t compromise a person’s independence. People with MCI may or may not develop Alzheimer’s dementia. For now, the identification of people as having MCI due to Alzheimer’s also is largely for research purposes.
  • Alzheimer’s Dementia: This refers to the stage of the disease when symptoms are evident and causing problems. It is the Alzheimer’s dementia stage that is divided into mild, moderate, and severe, as described below.

Mild (Early-Stage)

In general, people in the early stage of Alzheimer’s have memory problems that make it more difficult to absorb new information. They may lose or misplace objects. Planning and organizing become difficult. It becomes increasingly more difficult to perform daily activities, such as shopping, cooking, or keeping appointments.

People in the mild stage of Alzheimer’s still are able to have coherent conversations, but they may have trouble finding the right words or remembering names.

Moderate (Middle-Stage)

In the moderate stage of Alzheimer’s, the memory loss worsens, and it is more obvious to others. But highly learned information (such as the person’s birthday) and procedural memory (how to brush the teeth) are usually retained. In this stage, the names and identities of family members or close friends may become confused.

In the moderate stage, the person with Alzheimer’s is not able to manage money at all. Before this happens, it is important that arrangements be made regarding the handling of finances. This is especially important because cognitively impaired older adults can become victims of financial fraud schemes. Problem solving and judgment are generally impaired to the point where the person may not be able to handle a household emergency or make a decision about a stranger at the door.

Also, in this stage, judgment about how to respond socially declines. It’s not uncommon for people to act inappropriately in social situations, using coarse language or telling crude jokes. The enjoyment of social events and outings does not necessarily diminish. However, people with Alzheimer’s may avoid social situations because of embarrassment about their condition and their inability to process new and complex information.

In the moderate stage, the person continues to be able to read and understand what they are reading, and comprehend what people say to them. But the ability to formulate coherent sentences and to name objects deteriorates. As it becomes more difficult to retrieve desired words, speech may become vague and imprecise. And as the ability to produce spontaneous sentences diminishes, the person may resort to repeating commonly used phrases over and over in a conversation.

Severe (Late-Stage)

In the severe stage of Alzheimer’s, long-term memories will gradually fade, along with highly learned information and activities. The person may still recognize people who are always around, or with whom they’ve had a longstanding relationship, but will not be able to verbalize the people’s names or any other information about them.

In the severe stage, when many aspects of memory function are impaired and the person needs help with most activities of daily living, language comprehension and expression are both severely diminished. However, a person in the severe stage still may be able to recognize his or her name and respond when addressed directly. The ability to produce coherent sentences will vary from person to person—at this stage, some people with Alzheimer’s do not speak at all.

In the severe stage, problem solving and judgment are significantly impaired, and even simple decisions—such as what to eat and wear—must be supervised.

To learn more about AD, purchase Alzheimer’s Disease at

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Lynne Christensen

Lynne Christensen is executive editor of the Cleveland Clinic Arthritis Advisor newsletter. After completing her undergraduate degree from New York University, Christensen earned a master’s degree in biological studies from … Read More

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