Naomi Feil, who developed Validation in the 1960's, didn't like how the word dementia described the people she was working with - "de" means "away from" and "mentia" or mentus mean "mind". Her clients were not away from their minds, they were away from our present day reality. They were in their own personal reality.
The word Alzheimer's is now used indiscriminately. Depending on who is using it, it can cover any person who has symptoms of dementia.
Dementia is not a diagnosis; it is a set of symptoms that are caused by many different illnesses.
Alzheimer's disease has two forms: early onset and late onset.
Early onset usually begins between 50 - 60 years of age, sometimes earlier and sometimes a bit later. But it does not begin in "old-old" age (around 80 years old.) People with early onset Alzheimer's disease get worse, it is a degenerative disease. Medication helps keep the symptoms at bay for a few years. Speech is affected and people lose the ability to form sentences early in the process. There is no known cure and there is no way to definitely diagnose this disease - even with all the progress that has been made in this field.
Late onset begins in "old-old" age (+/- 80 years old); people with late onset Alzheimer's do not always get worse. It is not necessarily a degenerative disease. Diagnosis is made by ruling out all other forms of dementia - it is a diagnosis of exclusion.
In Validation theory, physical losses (loss of brain cells, reduced eye sight and hearing, and other normal physical problems that naturally occur in old age), psychological losses (the loss of loved ones, loss of a "home" when the person moves out of their home, loss of job and feelings of usefulness) and social losses (loss of regard by society, loss of status, increasing isolation) overwhelm a person in old-old age. People who have flexible coping skills find a way of dealing with these challenges; people who do not have flexible coping skills struggle against this avalanche of losses. It is this struggle that we see in the final life stage - resolution versus vegetation, which is an increasing withdrawal from the "here and now", our reality and into their own, personal reality.
An 85 year old woman, living with her daughter and son in law, blames her daughter for stealing all her money and her home. The reality is that this woman sold her home unwillingly; she forgets where she put her checkbook and does not know how to use an ATM. She has short term memory loss and never really accepted her retirement as the head bookkeeper for a large company.