Alzheimer's disease (AD) is the major cause of dementia and one of the leading causes of morbidity and mortality among the elderly. After Alzheimer's disease (AD) and vascular dementia, dementia with Lewy bodies (DLB) is one of the most common types of dementia. Because of the clinical heterogeneity and overlap with other neurodegenerative disorders, DLB can be difficult to diagnose. The descriptive point, where ratios are calculated for communities and populations in an attempt to explain phenotypic variances seen by identifying risk variables, to examine in epidemiological surveys on dementia. Dementia rates are increasing at an alarming rate in all parts of the world, and this is linked to population ageing.