The Brave study includes measurements of amyloid in the brain and cerebro-spinal fluids over several years...as well as studies of cognition over the years. Brave is an unusually thorough study, being focused on whether Vascepa helps patients to avoid developing Alzhheimers disease or to ameliorate it, if it develops.
The University of Wisconsin medical school and the VA did this scientific study, which Amarin could not have afforded to do by itself.