Alzheimer's disease typically progresses slowly in three general stages — mild (early stage), moderate (middle stage), and severe (late stage). Since Alzheimer's affects people in different ways, the timing and severity of dementia symptoms varies as each person progresses through the stages of Alzheimer's differently.
Overview of disease progression
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People with cognitive changes caused by Mild Cognitive Impairment (MCI) have an increased risk of developing Alzheimer's or another dementia. However, not all people with MCI develop Alzheimer's.
The symptoms of Alzheimer's disease worsen over time, although the rate at which the disease progresses varies. On average, a person with Alzheimer's lives four to eight years after diagnosis, but can live as long as 20 years, depending on other factors.
Changes in the brain related to Alzheimer's begin years before any signs of the disease. This time period, which can last for years, is referred to as preclinical Alzheimer's disease.
The stages below provide an overall idea of how abilities change once symptoms appear and should only be used as a general guide. (Dementia is a general term to describe the symptoms of mental decline that accompany Alzheimer’s and other brain diseases.)
The stages are separated into three categories: mild Alzheimer's disease, moderate Alzheimer's disease and severe Alzheimer's disease. Be aware that it may be difficult to place a person with Alzheimer's in a specific stage as stages may overlap.
Mild Alzheimer's disease (early stage)
In the early stage of Alzheimer's, a person may function independently. He or she may still drive, work and be part of social activities. Despite this, the person may feel as if he or she is having memory lapses, such as forgetting familiar words or the location of everyday objects.
Friends, family or others close to the individual begin to notice difficulties. During a detailed medical interview, doctors may be able to detect problems in memory or concentration. Common difficulties include:
- Problems coming up with the right word or name
- Trouble remembering names when introduced to new people
- Challenges performing tasks in social or work settings.
- Forgetting material that one has just read
- Losing or misplacing a valuable object
- Increasing trouble with planning or organizing
Although the onset of Alzheimer's disease cannot yet be stopped or reversed, an early diagnosis can allow a person the opportunity to live well with the disease for as long as possible and plan for the future.
Moderate Alzheimer's disease (middle stage)
Moderate Alzheimer's is typically the longest stage and can last for many years. As the disease progresses, the person with Alzheimer's will require a greater level of care.
During the moderate stage of Alzheimer’s, the dementia symptoms are more pronounced. A person may have greater difficulty performing tasks, such as paying bills, but they may still remember significant details about their life.
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You may notice the person with Alzheimer's confusing words, getting frustrated or angry, or acting in unexpected ways, such as refusing to bathe. Damage to nerve cells in the brain can make it difficult to express thoughts and perform routine tasks.
At this point, symptoms will be noticeable to others and may include:
Forgetfulness of events or about one's own personal history
Feeling moody or withdrawn, especially in socially or mentally challenging situations
Being unable to recall their own address or telephone number or the high school or college from which they graduated
Confusion about where they are or what day it is
The need for help choosing proper clothing for the season or the occasion
Trouble controlling bladder and bowels in some individuals
Changes in sleep patterns, such as sleeping during the day and becoming restless at night
An increased risk of wandering and becoming lost
Personality and behavioral changes, including suspiciousness and delusions or compulsive, repetitive behavior like hand-wringing or tissue shredding
Learn more: 10 Signs of Alzheimer's Disease, Diagnosis, Diagnosed with Alzheimer's, Types of Dementia,
Daily Care, Behaviors
Severe Alzheimer's disease (late stage)
In the final stage of this disease, dementia symptoms are severe. Individuals lose the ability to respond to their environment, to carry on a conversation and, eventually, to control movement. They may still say words or phrases, but communicating pain becomes difficult. As memory and cognitive skills continue to worsen, significant personality changes may take place and individuals need extensive help with daily activities.
At this stage, individuals may:
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Need round-the-clock assistance with daily activities and personal care
Lose awareness of recent experiences as well as of their surroundings
Experience changes in physical abilities, including the ability to walk, sit and, eventually, swallow
Have increasing difficulty communicating
Become vulnerable to infections, especially pneumonia
Learn more: Late-Stage Care