Overview
Parasomnias are defined as any undesirable physical events or experiences that occur during entry into sleep, within sleep, or during arousals from sleep. This includes a wide range of phenomenon encompassing abnormal sleep related movements, behaviours, emotions, dreaming, and physiological disturbances. Parasomnias may lead to significant sleep disturbances, physical injuries and other adverse medical or psychosocial effects. Moreover, parasomnias may affect not only the individual experiencing them, but also their bed partners and others around them.
The parasomnias can be divided into the following categories:
1. Disorders of arousal from non-rapid eye movement (NREM) sleep. Sometimes known as NREM parasomnias, this category includes confusional arousals, sleepwalking (somnambulism) and sleep terrors.
2. Parsomnias usually associated with rapid eye movement (REM) sleep. This includes REM sleep behaviour disorder, recurrent isolated sleep paralysis and nightmare disorder.
3. Other Parasomnias. This includes a variety of phenomena that do not readily fit into the above two categories. Recognized parasomnias in this category include sleep related dissociative disorder, sleep enuresis, sleep related groaning, exploding head syndrome, sleep related hallucinations, and sleep related eating disorder (see other)
