Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

The relative importance of Lewy- and Alzheimer-type pathologies to dementia in Parkinson s disease remains unclear. We have examined the combined associations of a-synuclein, tau and amyloid-b accumulation in 56 pathologically confirmed Parkinson s disease cases, 29 of whom had developed dementia. Cortical and subcortical amyloid-b scores were obtained, while tau and a-synuclein pathologies were rated according to the respective Braak stages. Additionally, cortical Lewy body and Lewy neurite scores were determined and Lewy body densities were generated using morphometry. Non-parametric statistics, together with regression models, receiver-operating characteristic curves and survival analyses were applied