Distribution and Load of Amyloid-β Pathology in Parkinson Disease and Dementia with Lewy Bodies

Parkinson disease (PD), Parkinson disease with dementia (PDD), and Dementia with Lewy bodies (DLB) differ clinically with regard to the presence and timing of dementia. In this postmortem study, we evaluated whether the burden and distribution pattern of amyloid-beta (A beta) pathology differs among these disease entities. We assessed A beta phases and neuritic plaque scores in 133 patients fulfilling clinical diagnostic criteria for PD, PDD, and DLB, and determined the presence and load of Ab pathology in 5 cortical and 4 subcortical regions in a subset of patients (n = 89) using a multispectral imaging system. A beta phases and neuritic plaque scores were higher in DLB versus PDD (both p<0.001) and in PDD vs PD patients (p = 0.020 and 0.022, respectively ). A beta pathology was more often observed in the entorhinal cortex, amygdala and putamen in DLB versus PDD patients; A beta load was higher in both cortical and subcortical regions. PDD patients had more frequent A beta pathology in temporal cortex and higher A beta load in cortical regions and striatum versus PD patients. Our findings suggest that the load and extent of A beta pathology may contribute to cognitive dysfunction in PDD and the early-stage severe dementia in DLB.