WBR0925

Author	[[PageAuthor::Twinkle Singh, M.B.B.S. [1] (Reviewed by Serge Korjian and Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::A 6-year-old boy is brought to the pediatrics clinic by his concerned mother. She explains that her son often wakes up during the night screaming and continues to cries inconsolably. However, in the morning he appears to be normal and doesn’t remember anything regarding the incident the previous night. The physician suggests a sleep study to further evaluate the child's condition. Which of the following wave forms are most likely to be observed directly prior to this patient's episodes?]]
Answer A	AnswerA::Theta waves
Answer A Explanation	AnswerAExp::Theta waves occur mostly during stage 1 NREM sleep.
Answer B	AnswerB::Beta waves
Answer B Explanation	[[AnswerBExp::Beta waves are characteristic of rapid eye movement (REM) sleep and are also demonstrated when a person is awake and alert. Nightmares occur during REM sleep which may present similar symptoms, but with a nightmare the child usually has memory of the dream.]]
Answer C	AnswerC::Sleep spindles and K-complexes
Answer C Explanation	AnswerCExp::Sleep spindles and K-complexes are characteristics of NREM stage 2. Bruxism occurs commonly during this stage.
Answer D	AnswerD::Delta waves
Answer D Explanation	AnswerDExp::Sleep terrors occur during delta sleep (stages 3 and 4 NREM sleep) characterized by delta waves.
Answer E	AnswerE::Alpha waves
Answer E Explanation	AnswerEExp::Alpha waves are found in EEG when a person is awake with closed eyes.
Right Answer	RightAnswer::D
Explanation	[[Explanation::Sleep terror is a type of parasomnia which is most likely to occur during stages 3 and 4 of non-rapid eye movement (NREM) sleep. NREM sleep is also known as delta sleep or slow wave sleep and is characterized by the highest amplitude and the lowest frequency waves among all sleep stages. The most common age group affected by sleep terrors is 4 to 12 years. Commonly, sleep terrors are associated with waking up in panic, inconsolable crying, autonomic arousal (tachycardia, sweating and hyperventilation), no memory of the episode, and no recollection of any nightmare. Reassurance is often recommended with improvement of sleep hygiene. Other parasomnias such as bed wetting and sleep walking also occur during the delta sleep stage. Educational Objective: Sleep terror is a type of parasomnia which is most likely to occur during stages 3 and 4 of non-REM sleep (delta waves stage). References: Ohayon MM, Guilleminault C, Priest RG. Night terrors, sleepwalking, and confusional arousals in the general population: their frequency and relationship to other sleep and mental disorders. J Clin Psychiatry. 1999;60(4):268-76.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Sleep, WBRKeyword::Sleep terrors, WBRKeyword::Sleep hygiene, WBRKeyword::REM, WBRKeyword::Non-REM, WBRKeyword::Rapid eye movement, WBRKeyword::Delta waves
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