Dementia is progressive loss of cognitive function, marked by memory problems, trouble communicating, impaired judgment, and confused thinking. It is caused by damage to brain cells and usually worsens over time. Dementia most often occurs during old age, but is a more severe form of decline than normal aging. People who develop dementia may lose the ability to regulate their emotions, especially anger; their personalities may even change. There are multiple stages of dementia, ranging from some minor difficulty functioning to severe impairment. In the most severe stage, people with dementia are completely dependent on the help of others for the basic activities of daily life, such as keeping themselves clean and fed. The most common form of dementia is Alzheimer's Disease, a fatal condition that affects more than 5 million Americans. There is currently no cure for most types of dementia, but certain treatments can help alleviate the symptoms temporarily.