Dementia

Dementia is a broad category of brain diseases that cause a long-term and often gradual decrease in the ability to think and remember that is severe enough to affect daily functioning. Other common symptoms include emotional problems, difficulties with language, and a decrease in motivation.
The most common type of dementia is Alzheimer's disease, which makes up 50% to 70% of cases. Other common types include vascular dementia (25%), dementia with Lewy bodies (15%), and frontotemporal dementia. Less common causes include normal pressure hydrocephalus, Parkinson's disease dementia, syphilis, HIV, and Creutzfeldt–Jakob disease. More than one type of dementia may exist in the same person.
Alzheimer's disease (AD), also referred to simply as Alzheimer's, is a chronic neurodegenerative disease that usually starts slowly and gradually worsens over time. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, not managing self-care, and behavioural issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years.