Parasomnia disorders

**Definition:** Parasomnias are problematic behavioural or physiological events that occur while falling asleep, during sleep, or upon arousal from sleep. Parasomnias may occur during non-rapid eye movement sleep (NREM), rapid eye movement sleep (REM), or during transitions to and from sleep. They encompass abnormal sleep related complex movements, behaviours, emotions, perceptions, dreams, and autonomic nervous system activity.