Dementia with Lewy bodies (DLB) is the third most common cause of dementia.
Lewy bodies are tiny round clumps of protein that builds up inside brain cells. They stop brain cells from working properly, causing dementia symptoms such as memory loss.
They can cause other problems too, such as hallucinations (seeing things that are not there), slowed movements and changes with sleep behaviour causing people to move around in their sleep or talk in their sleep.
People with DLB often have big differences between their good days and their bad days. On bad days they may be more confused and less alert.