Rumors were that she suffered some kind of a stroke, back when she was seen wearing special coke-bottle thick glasses.
An Opthamologist stated the glasses were used to treat a kind of double-vision associated with head trauma.
http://www.foxnews.com/health/2014/05/16/ophthalmologist-weighs-in-on-clinton-glasses-spectacle/
Hillary had a stroke at the office and no one cared enough to catch her when she fell and slammed her head on the floor.