Night terrors are sleep disturbances in which children may suddenly bolt upright in bed, crying, screaming, moaning, mumbling, and thrashing about with their eyes wide open, but without being truly awake. Because they are caught in a sort of a twilight zone between being asleep and being awake, they are unaware of your presence and are not likely to respond to anything you say or do. In fact, researchers think of night terrors as mysterious glitches in the usually smooth transitions we make each night between sleep stages. As many as 15 percent of children have night terrors at some point, typically beginning in the toddler and preschool years and continuing up to age 7 or even adolescence. An episode can last anywhere from two to 40 minutes, and when it's over your child falls back to sleep abruptly with no memory of the incident. Parents often feel helpless since the child is not aware of their presence during an episode.