Dementia with Lewy bodies (DLB) is being increasingly recognized as a common cause of progressive cognitive decline in the elderly, with hospital-based autopsy series demonstrating rates of between 7% and 25% of all cases of dementia, second only in frequency to Alzheimer's disease (AD). Although DLB has only recently been described, it is unlikely to be a newly occurring disease but one which has become identifiable as a result of advances in neuropathological techniques which make cortical Lewy bodies (LBs) easier to detect.