There is a good deal of debate about the roll of protein plaques in Alzheimer's. I follow dementia research as best I can (I am not a scientist) but at least one attempt at fighting the plaques seemed to have accelerated the Alzheimer's. So there is a theory that some other mechanism is causing the brain damage associated with Alzheimer's and that the plaques are a defense mechanism. But dementia research is difficult, it is not a disease.
But back to the paper which is really about protein plaques. It is very interesting and I wish I had the background to better understand it.