What are the stages of Alzheimer's disease?

The following stages represent the general course the disease follows, but moving from one stage to another may not be perceptible due to the fact that the symptoms are on a gradual continuum of severity.

Pre-clinical/Pre-symptomatic Stage:

Physical conditions connected to Alzheimer’s disease exist in a person’s body long before symptoms are evident. These conditions are normally defined through the use of “biomarker” tests, like those searching for beta-amyloid and tau proteins in blood and cerebrospinal fluid, and specialized PET and MRI scans. Currently, this stage is only defined in research settings and clinical trials and is unlikely to be given as an official clinical diagnosis by a health professional.

Mild Cognitive Impairment (MCI) Due To Alzheimer’s Disease/Prodromal Stage:

Recently, scientists have identified a condition between normal age-related memory loss and dementia called mild cognitive impairment (MCI). Individuals with MCI have persistent memory problems (for example, difficulty remembering names and following conversations and marked forgetfulness) but are able to perform routine activities without more than usual assistance. MCI often leads to Alzheimer’s, but while all those who progress to some form of dementia go through a period of MCI, not all patients exhibiting MCI will develop Alzheimer’s disease. An official clinical diagnosis of MCI can be given by a health professional.

Dementia Due To Alzheimer’s Disease (Mild, Moderate, Severe Stages):

Mild (Stage 1)

Early in the illness, people with Alzheimer’s tend to lose energy and spontaneity, though often no one notices anything unusual. They exhibit minor memory loss and mood swings and are slow to learn and react. After a while they start to shy away from anything new and prefer the familiar. In this stage, Alzheimer’s patients can still perform basic tasks independently but may need assistance with more complicated activities. Speech and understanding become slower, and patients often lose their train of thought in midsentence. They may also get lost while traveling or forget to pay bills. As they become aware of this loss of control, they may become depressed, fearful, irritable, and restless.

Moderate (Stage 2)

Eventually, people with the illness begin to be disabled by it. Though the distant past may be recalled, recent events become difficult to remember. Advancing Alzheimer’s affects the ability to comprehend location, the day, and the time. Caregivers must give clear instructions and repeat them often. As Alzheimer’s patients’ minds continue to slip away, they may invent words and not recognize formerly familiar faces.

Severe (Stage 3)

During the final stage, patients become more and more unresponsive. Memory becomes so poor that no one is recognizable. Patients lose bowel and bladder control and eventually need constant care. They lose the ability to chew and swallow and become bedridden and vulnerable to pneumonia, infection, and other illnesses. Respiratory problems worsen, particularly when the patient becomes bedridden. This terminal stage eventually leads to coma and death.

Resources:

• Alzheimer's Toolkit (Information to Help You Understand and Manage Alzheimer's Disease)
• Expert Articles on Alzheimer's
• Questions and Answers about Alzheimer's