Parasomnia NREM parasomnia 2016-12-14T11:55:11Z A parasomnia that occurs during non-rapid eye movement (NREM) sleep. NREM parasomnias typically occur within a few hours after the onset of sleep. Episodes can last from a few minutes to as long as 30-40 minutes and are characterized by amnesia for the event. Disturbance in NREM Non-rapid eye movement parasomnia NREM parasomnia