Tags: Disease.
A night terror sleep terror or pavor nocturnus is a parasomnia disorder causing feelings of terror or dread and typically occurring in the first few hours of sleep during stage 3 or 4 non-rapid eye movement (NREM) sleep. Night terrors tend to happen during periods of arousal from delta sleep also known as slow-wave sleep. During the first half of a sleep cycle delta sleep occurs most often which indicates that people with more delta sleep activity are more prone to night terrors.