Duhaime's Law Dictionary Parasomnia Definition: Sudden unexplained arousal from sleep, sometimes combined with sleep-walking or hand gestures or other bizarre activities. Related Terms: Automatism, Narcolepsy In R v Luedecke, Justice David Doherty of the Court of Appeal for Ontario adopted these words from medical expert evidence:"Parasomnia involves a sudden unexplained arousal from sleep. Persons may carry out various physical activities while in a parasomniac state. Usually those activities are not complex, and may include hand gestures, talking, or walking. More rarely, an individual in a parasomniac state engages in complex physical activity that can include eating, sexual acts, or driving a vehicle. Physical activities performed by a person in a parasomniac state are often bizarre but can appear purposive. Parasomniacs are seldom violent."REFERENCES:R. v. Luedecke, 2008 ONCA 716 Categories & Topics: Duhaime & Naysmith Medical-Legal Dictionary Always looking up definitions? Save time with our search provider (modern browsers only) If you find an error or omission in Duhaime's Law Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!