Dementia is the loss of cognitive functioning thinking, remembering, and reasoning and behavior alabilities to such an extent that it interferes with a persons daily life and activities. These functions include memory, language skills, visual perception, problem solving, self-management, and the ability to focus and pay attention. Some people with dementia cannot control their emotions, and their personalities may change. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a persons functioning, to the most severe stage, when the person must depend completely on others for basic activities of living.