Meaning of parasomnia: Because episodes occur during sleep or its transitions, the person experiencing a parasomnia often has no memory of it afterward.

Definition of parasomnia

Parasomnia is a category of sleep disorders involving abnormal movements, behaviors, emotions, or perceptions that occur while falling asleep, during sleep itself, or while waking. Rather than disrupting the ability to fall or stay asleep, a parasomnia produces an unusual event during sleep, and the person affected frequently has little or no memory of the episode afterward.

Common examples of parasomnia include sleepwalking, sleep talking, night terrors, nightmares severe enough to cause distress, and rapid eye movement sleep behavior disorder, in which a person physically acts out dream content. Bedwetting occurring during sleep is also classified as a parasomnia in some frameworks.

Parasomnias are distinguished from sleep related breathing disorders, such as sleep apnea, which involve abnormal breathing patterns during sleep rather than the abnormal behaviors or perceptions that define a parasomnia, though the two categories are sometimes grouped together informally despite describing different underlying problems.

Used in a sentence

The sleep study was ordered to evaluate a parasomnia involving frequent sleepwalking episodes.

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Good to know

Sleep apnea is sometimes grouped informally with parasomnias, though it is classified separately as a sleep related breathing disorder rather than as a parasomnia, which describes abnormal behavior during sleep.

Word origin

Where “parasomnia” comes from

Formed from Greek para-, meaning beside or abnormal, and Latin somnus, meaning sleep, combined with the suffix -ia.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.