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Alzheimer’s Disease Stages

People can suffer from Alzheimer’s disease for over a decade, but the experience is not uniform over the years. Instead, the disease progresses, getting worse over time and evolving through stages. The progression of the disease can be categorized into different stages. There is no one way to categorize these stages, but the 5 stages below represent 5 generally accepted phases of Alzheimer’s disease.

 Preclinical Alzheimer’s disease

The preclinical phase of Alzheimer’s disease refers to the time before symptoms appear but when changes in the brain that are indicative of the disease are already taking place. Specifically, imaging studies can identify amyloid beta protein in the brain during the preclinical stage.

Mild cognitive impairment

Mild cognitive impairment, or MCI, represents the next stage of Alzheimer’s disease, where memory and thinking are affected. In this phase, though symptoms of the disease emerge, they are not pronounced enough to significantly impact interactions with people or work performance. Though a person undergoing mild cognitive impairment may begin having difficulties with decision making and judgment, the symptoms do not tend to catch the attention of others and may not even be particularly noticeable to the person experiencing them.

Mild dementia

It is during the mild dementia stage that an Alzheimer’s diagnosis is often made, which is often the result of other people in the patient’s life recognizing that the person is struggling with their thinking or memory. During the mild dementia stage, memory loss is experienced more significantly than in the MCI phase, often involving difficulty remembering details of recent events. Other things that occur during this stage are changes in personality, disorientation, difficulty organizing thoughts, and difficulty with problem solving.

Moderate dementia

Moderate dementia usually lasts longer than any other stage of Alzheimer’s disease.  The difficulties that the patient experienced during the mild dementia phase are exacerbated during moderate dementia, making the disease more frustrating for the patient. During this phase, the patient needs more care and monitoring, as the damage to the brain progresses, and thoughts and behaviors are more affected and other difficulties arise. Patients may have trouble sleeping, as well as controlling their bladder and bowels during this stage.

Severe dementia

When patients are in the severe dementia stage, they require full-time care because they are no longer able to appropriately respond to their environment. All of the previous symptoms get even worse during this stage, and physical abilities decline during this stage as well.


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