Dementia is a progressive loss of cognitive function, marked by memory problems, trouble communicating, impaired judgment, and confused thinking. Dementia most often occurs around age 65 and older 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, and their personalities may change.| Psychology Today
Memory is the faculty by which the brain encodes, stores, and retrieves information. It is a record of experience that guides future action.| Psychology Today
Cognition refers, quite simply, to thinking. There are the obvious applications of conscious reasoning—doing taxes, playing chess, deconstructing Macbeth—but thought takes many subtler forms, such as interpreting sensory input, guiding physical actions, and empathizing with others.| Psychology Today