Alzheimer's disease affects people in different ways, making it difficult for medical professionals to predict how an individual's disease will progress. People diagnosed with Alzheimer's disease may live from 2 to 20 years after the onset of memory loss. The disease may shorten one's life expectancy, but given appropriate care and medical attention, patients often survive for many years at home or in a nursing home. It is common for patients in terminal stage Alzheimer's to lose weight, and to have difficulty swallowing, controlling bladder and bowels, walking and speaking. They may curl into a fetal position. Alzheimer's victims often succumb to a series of repeated infections such as bladder infections or pneumonia.

Some experts classify the disease by stage (early, middle and late). But specific behaviors and how long they last vary greatly, even within each stage of the disease. However, symptoms seem to progress in a recognizable pattern and these stages provide a framework for understanding the disease. It is important to remember they are not uniform in every patient and the stages often overlap.