Alzheimer's stages: How the disease progresses

Alzheimer's disease can last more than a decade. See what types of behaviors are common in each of the stages as the disease progresses.

By Mayo Clinic Staff

Alzheimer's disease typically develops slowly and gradually gets worse over the course of several years. It eventually affects most areas of your brain, including those important in memory, thinking, judgment, language, problem-solving, personality and movement.

There are five stages associated with Alzheimer's disease: preclinical Alzheimer's disease, mild cognitive impairment, mild dementia due to Alzheimer's, moderate dementia due to Alzheimer's and severe dementia due to Alzheimer's. Dementia describes a group of symptoms affecting intellectual and social abilities severely enough to interfere with daily functioning.

These stages can help you and your family understand what to expect and plan for the future. It's important to realize that Alzheimer's stages are rough guides based on averages and generalizations. The disease is a continuous process. Your experience with Alzheimer's, the symptoms you develop and when they appear may vary.

Preclinical Alzheimer's disease

Alzheimer's disease begins long before any symptoms become apparent. This stage is called preclinical Alzheimer's disease. You won't notice symptoms during this stage, nor will those around you. This stage of Alzheimer's can last for years, possibly even decades.

Although you won't notice any changes, new imaging technologies can now identify deposits of a substance called amyloid beta that have been associated with Alzheimer's disease. The ability to identify these early deposits may be especially important as new treatments are developed for Alzheimer's disease.

Mild cognitive impairment (MCI) due to Alzheimer's disease

People with mild cognitive impairment have mild changes in their memory and thinking ability. These changes aren't significant enough to affect work or relationships yet. People with MCI may have memory lapses when it comes to information that is usually easily remembered, such as conversations, recent events or appointments. People with MCI may also have trouble judging the amount of time needed for a task, or they may have difficulty correctly judging the number or sequence of steps needed to complete a task. The ability to make sound decisions can become harder for people with MCI.

Not everyone with mild cognitive impairment has Alzheimer's disease. In some cases, MCI is due to depression or a temporary medical complication. The same procedures used to identify preclinical Alzheimer's disease can help determine whether MCI is due to Alzheimer's disease or something else.

Mild dementia due to Alzheimer's disease

Alzheimer's disease is often diagnosed in the mild dementia stage, when it becomes clear to family and doctors that a person is having significant trouble with memory and thinking.

In the mild Alzheimer's stage, people may experience:

  • Memory loss for recent events. Individuals may have an especially hard time remembering newly learned information and repeatedly ask the same question.
  • Difficulty with problem-solving, complex tasks and sound judgments. Planning a family event or balancing a checkbook may become overwhelming. Many people experience lapses in judgment, such as when making financial decisions.
  • Changes in personality. People may become subdued or withdrawn — especially in socially challenging situations — or show uncharacteristic irritability or anger. Decreased attention span and reduced motivation to complete tasks also are common.
  • Difficulty organizing and expressing thoughts. Finding the right words to describe objects or clearly express ideas becomes increasingly challenging.
  • Getting lost or misplacing belongings. Individuals have increasing trouble finding their way around, even in familiar places. It's also common to lose or misplace things, including valuable items.
Jan. 04, 2013 See more In-depth