My boyfriend has T1 diabetes and has had a few seizures -- the first sign I've seen that his blood sugar is going low at night is being woken up by twitching. When I try to get some sugar to him, he's usually very confused and unable to control his movements. He gets less and less responsive until his eyes get wide, and he stares off into the distance. Then he looks terrified: like there's something off in the distance that is shaking him to his core -- a couple times he let out the worst kind of horrified sound/moan -- then he goes totally blank. That's when I know I have only a couple seconds to catch him and try to reduce the damage on his way down and while it's happening...

... His diabetes is better under control now and he hasn't had one in over a year, thankfully.