Question: what are the four main types of dementia?
Answer: Alzheimer's Disease. This is the most common type of dementia. ... 
Lewy Body Dementia (or Dementia with Lewy Bodies). Lewy Body Dementia is another very common, yet frequently misdiagnosed, or undiagnosed type of dementia. ... 
Vascular Dementia. ... 
Fronto Temporal Dementia.