How are alzheimer's disease and dementia different?

See below: Alzheimer's disease is one of the diseases that cause dementia. Dementia is a syndrome that can be also caused by a stroke, dementia with lewy bodies, brain injury, normal pressure hydrocephalus and other conditions.

Square vs. Rectangle: Dementia is a term for a group of disorders that are characterized by degeneration of certain parts of the brain and cause problems with thinking, comprehension, language and various other cognitive abilities. Alzheimer's dementia is one kind of dementia. Just as all squares are rectangles, but the not all rectangles are squares, alzheimer's is a kind of dementia, but the reverse is not true.