Progression of Alzheimer's Disease

Alzheimer's disease is a progressive, degenerative disease that destroys vital brain cells. As each area of the brain is affected, certain functions or abilities can be lost. The losses affect the individual's ability to think, to remember, to understand and to make decisions. In addition to affecting a person's mental abilities, Alzheimer's disease affects moods and emotions. Along with loss of abilities, changes in behaviour occur. Gradually, independence disappears.

Approach to care

It is important to remember that the approach to care can enhance the individual's quality of life. The Alzheimer Society developed the Guidelines for Care to ensure that people with Alzheimer's disease receive the special type of care that reflects the unique nature of the disease.

A person-centred approach to care recognizes that each individual deserves to be treated with dignity and respect. By understanding the person's personality, life experiences, support systems and ways of coping, the individual's physical, social, emotional and spiritual needs can be met.

Although the person loses many abilities as the disease progresses, it is helpful to focus on the abilities that do remain, such as the senses of touch and hearing, and the ability to respond to emotion.

Duration of the disease

The progression of Alzheimer's disease varies from person to person and can span three to 20 years (the average length of the disease is between eight and 12 years1). The progression can be described as a series of stages, providing a guide to the pattern of the disease, which can help when making care decisions.

One staging system explains the disease in three stages: early, middle and late. Another staging system, often used by medical professionals, is the Global Deterioration Scale (also called the Reisberg Scale2). This scale divides the disease into seven stages.

Which ever staging system is used, or if none is used, it's important to remember that the disease affects each person differently. The order in which the symptoms appear and the length of each stage will vary from person to person. There is no clear line when one stage ends and another begins. In many cases, stages will overlap. Some people experience many of the symptoms in each stage, while others experience only a few. There may be fluctuations from day to day with a person appearing more confused one day, for example, and less so another.