Non-rapid eye movement (NREM) sleep arousal disorders refer to the repeated episodes of incomplete awakening from sleep that include behaviors such as sleepwalking and sleep terrors. These episodes usually happen during the first third of the night and people will be confused and disoriented if awakened during an episode. People with this condition have no memory of their dreams or sleep behavior in the morning.
NREM sleep arousal disorders occur most commonly in childhood and happen less often with advancing age. Isolated or infrequent NREM sleep arousal disorders are common, with 10 to 30 percent of children having had at least one episode of sleepwalking; 2 to 3 percent of children sleepwalk often. The prevalence of sleepwalking episodes among adults is in the range of 1 to 7 percent, but far fewer adults have episodes on a regular basis. Sleepwalking occurs more often in females during childhood and more often in males during adulthood.