"So if the plaques are that different and RCT is out then what mechanism would one surmise that 208 could be responsible for if it can increase mental cognition in the elderly"

Did you even glance at the paper I previously linked to? Also, see the CTAD and AAIC posters on the Resverlogix website and the abstracts for the upcoming AD/PD 2019 conference.

https://www.cell.com/cell-metabolism/fulltext/S1550-4131(14)00009-6

https://www.resverlogix.com/science-and-programs/publications#rvx-posters

https://agoracom.com/ir/Resverlogix/forums/discussion/topics/722420-ad-pd-2019-march-26-31-2019/messages/2220710#message