Pages in Dementia brain tour How does the brain work? How do brain cells work? What is dementia? What is Alzheimer's disease? You are here: What is vascular dementia? What is dementia with Lewy bodies? What is frontotemporal dementia? 5. What is vascular dementia? Vascular dementia is the second most common type of dementia although it can also occur it combination with Alzheimer's disease in a condition called mixed dementia. Previous section 4. What is Alzheimer's disease? Next section 6. What is dementia with Lewy bodies?