Neuropathology of dementia in a large cohort of patients with Parkinson's disease

All the three lesion types were more abundant in the demented PD group, compared to the non-demented PD group, but neocortical LB pathology was the most important substrate of dementia. A significant correlation was found between the severity of Aβ phases, NFT stages and cortical LB scores. In a subgroup of severely demented PD patients, cortical tau burden was much higher than in the rest of the group. Extensive cortical NFTs associate unavoidably with dementia. Some patients remain cognitively intact despite high cortical LB score. In conclusion, our data strongly support a combining, yet distinct role of neocortical LBs and tau deposits.