Fdr & Gbs?

I am currently reading Dr. Gareth Parry & Dr. Joel Stienberg’s new book simply entitled “Guillain Barre Syndrome” & they talk about whether or not FDR had GBS or polio. Apparently many of the world’s top neurologists on GBS have studied this issue & come to the conclusion that FDR probably did have polio, although I am not sure exactly why. They didn’t really elaborate much on the issue…