Dementia with Lewy bodies (DLB) is the currently preferred term for a variety of clinical diagnoses that have risen to prominence during the last decade (McKeith et al., 1996). These include diffuse Lewy body disease, dementia associated with cortical Lewy bodies, the Lewy body variant of Alzheimer's disease (AD) (Hansen et al., 1990), senile dementia of the Lewy body type, and Lewy body dementia. Initially thought to be uncommon, DLB is now recognized as the second most common pathologic cause of dementia, accounting for up to 20% of all elderly cases reaching autopsy.