My daughter has experienced "spells" intermittently for 10years+/-. Initially she would feel suddenly unbalanced, dizzy,hot all over, and see "stars or spots", and weakness in her legs. In the last few years, the "spells " can occur several times a month, not apparently assoc with menstrual cycle, meals, or activity. Today, she had stepped out of the shower and was drying off and the symptoms came on aggressively and included total loss of vision lasting approx. 15secs. Additionally, she says her mouth is full of saliva. I have witnessed previous episodes, she does not break out in a sweat, her heart rate/BP/ and blood glucose have been WNL. But she looks Distressed...can't really explain it any better. The episodes pass quickly without intervention of food/sugar/fluid.