My son, now 3, has suffered from night terrors since he was a baby. I remember them from when he was 6 months old--he thrashed in my arms, screamed, and had that 'possesed' look in his eyes. They were regular for a while, them went away for a while, then came back for a while, etc. They were definitely more common when he was overtired, esp. when dropping a nap in the day time. Sometimes he even had them at naps. After he dropped from 2 to 1 nap a day, the terrors went away for a long time, until now, at 3, as he is dropping from 1 to no naps.
They are very hard for us, very prolonged. His whole body is tense, like a rock, and shaking. He is crying, screaming things like, 'no!!' and 'mama!!' I go to him and sit with him. If I try touching him it makes it worse. It is so hard, though because he is so upset!
I have looked them up online and at one point I found a site that had people who as adults remembered their terrors. They described things like seeing their mother there, but she was deformed into a monster, or different in some way. One person described seeing only spiders everywhere. I think it is not always true that they don't remember. My DH had them when he was little and he remembers too. I think if you do wake up and come completely out of it, then they can remember. Anyway, I have a lot of sympathy both for the children that have these and the parents that have to go through them as well!
I also read about waking them up 20-30 mins prior but I don't think we tried it. I also read about wetting their feet and keeping them uncovered, but a wet wash cloth sounds more effective than trying to get them to the bathroom. Another person said it seemed to be related to having to pee. I think it might be more like anything can trigger if it's the right moment, like having to pee, needing a sip of water (we have experienced both of these which were relieved when he got what he needed), or a noise, or just nothing.
Anyway, I'm always curious about people's experiences.