I have had eleven T.I.A.'s ovr the last eight years. My neurologist is great and has ruled out dozens of causes, so I thought I would try investigating some possible causes myself. Has anyone heard of a link between multiple concussions over the years and TIA's, or another subject is a link between long term (25 years) use of Premarin and TIA's. I really want to figure this out and try to stop them.