The changes in mental processes not only involve disturbances in memory but also in perception, the ability to learn, to solve problems and to think abstractly and make judgements. Senile dementia is simply dementia in the aging adult. This may be a consequence of Alzheimer's Disease but there may be other explanations, for example the effects of several small strokes. The duration of the disease is long, often five to ten years from diagnosis, and sufferers may spend the last five or more of those years under close care at home or in a nursing home. Individuals who are well looked after may survive physically even if they have a total loss of mental processes.
Death often results from other diseases - for example, heart disease, cancer, stroke or pneumonia.
The decrease in life expectancy associated with Alzheimer's Disease makes it the fourth or fifth leading cause of death. For unknown reasons women appear to be affected more than men. This is not due to their increased life expectancy. No statistics however can describe the gradual inevitable decline endured by the patient nor the stress and suffering experienced by the family and the carers. As people grow older, their memory becomes less good and they may worry that they have Alzheimer's Disease.