Again, what is causing the low blood flow to the brain? Why has my father remained completely clear-minded at 80, while his 82-year old brother is completely taken over by Alzheimers. His mind is almost completely gone. My father still writes articles for scholarly journals. Could it all be to hypoperfusion? And what does it mean for those of us who believe some dynamic, possibly weak tissue illness (EDS, and others) causes ME/CFS? Why has the connection been researched? Vasc Health Risk Manag. 2012;8:599-611. doi: 10.2147/VHRM.S34874. Epub 2012 Oct 23. Cerebral blood flow in Alzheimer's disease.