Dementia with Lewy bodies (DLB), also known as diffuse Lewy body disease, cortical Lewy body disease, and senile dementia of Lewy type, is a type of dementia accompanied by changes in sleep, behavior, cognition, movement, and automatic bodily functions. It is characterized by the presence of Lewy bodies, parts of alpha-synuclein and ubiquitin protein in neurons, detectable in "post mortem" brain histology.