Family history of dementia: dementia with lewy bodies and dementia in Parkinson's disease.

Parkinson's disease with dementia (PD-D) and dementia with Lewy bodies (DLB) may result from the same neurodegenerative process with different temporal and spatial courses. The authors report an association between DLB and family history of dementia in a comparison study between patients with a clinicopathological diagnosis of PD-D and DLB. Findings suggest that positive family history for dementia is associated with DLB with a yet unknown mechanism.