Dementia is a term used to describe a number of physical disorders of the brain arising from different causes. They all have in common a decline in mental function, especially memory.
Dementia affects daily activities and social relationships.
Dementia is usually progressive and irreversible. The disease typically begins with lapses in memory, mood swings and difficulty in finding the right words. As the disease progresses the patient suffers from permanent memory loss and impaired ability to learn, talk and cope with everyday activities. Concern about memory problems can be quite distressing for elderly people as they sometimes think they have Alzheimer's disease. Memory loss alone does not always indicate Alzheimer's disease or serious problems.