Relationship between Parkinson disease with dementia and dementia with Lewy bodies.

Parkinson disease (PD) and dementia with Lewy bodies (DLB) are considered Lewy body diseases (LBDs). To clarify the relation between PD with dementia (PDD) and DLB, 30 patients with LBD were divided into pathological subtypes according to the consensus guidelines for DLB. Patients with PDD showed neocortical and limbic type of LBD as well as patients with DLB. Dementia had not been noted in 2 patients with neocortical type. Our results indicate that PDD and DLB share a common pathological substrate and that the pathological subtypes of LBD show considerable overlap in clinical manifestations.