somnambulism /somnam″byəliz′əm/ [L, somnus, sleep, ambulare, to walk] , 1. a condition occurring during stage 3 or 4 of nonrapid eye movement sleep that is characterized by complex motor activity, usually culminating in leaving the bed and walking about. The person has no recall of the episode on awakening. The episodes, which usually last from several minutes to half an hour or longer, are seen primarily in children, are more common in boys than in girls, and are more likely to occur if the individual is fatigued or under stress or has taken a sedative or hypnotic medication at bedtime. Seizure disorders, central nervous system infections, and trauma may be predisposing factors, but the condition is more commonly related to anxiety. In adults, the condition is less common and is classified as a dissociative reaction. Also called noctambulation, sleepwalking, somnambulance. 2. a hypnotic state in which the person has full possession of the senses but no recollection of the episode. See also fugue.
