It’s quite interesting that Senator Johnson’s ailment turns out to be a congenital aterioveinous malformation (AVM). Why is that interesting? Because I had the same situation.  A week before my 16th birthday, I was sitting around my house and got a headache… a fairly strong one. Then I lost all vision on my left side. A trip to the emergency room and a CAT scan later and I was diagnosed with an AVM. I went through a series of procedures and on my 16th birthday went under the knife to have the deformed blood vessels removed from the occipital (vision) lobe of my brain. Fortunately my only lasting effect was a small vision loss in the extreme lower left portion of my field of vision.
So next time you think I’m full of crap, maybe it’s because part of my brain has been removed 
Best wishes to Senator Johnson for a good recovery.
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