Sleep-Wake Disorders Practice Questions

Q: Bruxism most commonly occurs during which phase of sleep?

NREM Stage II. **Explanation:** **Sleep Bruxism** is a sleep-related movement disorder characterized by the involuntary grinding or clenching of teeth. **Why NREM Stage II is correct:** While bruxism can occur in any stage of sleep, it is most frequently observed during **NREM Stage II (Light Sleep)**. Statistically, about 80% of bruxism episodes occur during NREM sleep, with the vast majority clustered in Stage II. These episodes are often associated with "micro-arousals"—brief shifts in sleep depth where the sympathetic nervous system activity increases, leading to rhythmic masticatory muscle activity (RMMA). **Analysis of Incorrect Options:** * **REM Sleep (A):** Although bruxism can occur during REM, it is less common. REM-related bruxism is often associated with more severe clinical symptoms and may be linked to obstructive sleep apnea. * **NREM Stage I (B):** This is a transitional phase of very light sleep. While grinding can occur here, the frequency is significantly lower than in Stage II. * **NREM Stage III (D):** Also known as Slow Wave Sleep (SWS) or deep sleep. Parasomnias like sleepwalking (somnambulism) and night terrors typically occur here, but bruxism is less frequent in this stage compared to Stage II. **High-Yield Clinical Pearls for NEET-PG:** * **Treatment of Choice:** The first-line management is usually **stress reduction** and **dental guards (occlusal splints)** to prevent tooth wear. * **Pharmacotherapy:** If severe, **Benzodiazepines** (like Clonazepam) or muscle relaxants may be used short-term. * **Association:** Bruxism is frequently associated with stress, anxiety, and other sleep disorders like Obstructive Sleep Apnea (OSA). * **Key Distinction:** Do not confuse bruxism (Stage II) with **Sleep Terrors/Somnambulism**, which are classic **Stage III (N3)** phenomena.

Q: Kleine-Levin syndrome is characterized by which of the following?

Hypersomnia. **Explanation:** **Kleine-Levin Syndrome (KLS)**, often referred to as "Sleeping Beauty Syndrome," is a rare, relapsing-remitting neurological disorder primarily affecting adolescent males. 1. **Why Hypersomnia is Correct:** The hallmark of KLS is **recurrent episodes of severe hypersomnia**, where patients may sleep for 15 to 21 hours a day. During these episodes, patients are difficult to arouse and exhibit cognitive disturbances (like derealization), irritability, and compulsive behaviors. 2. **Why Other Options are Incorrect:** * **Insomnia:** This is the inability to sleep. KLS is characterized by the polar opposite—excessive sleep duration. * **Depression & Anxiety:** While patients may experience mood changes or "flat affect" during an episode, these are secondary symptoms or part of the post-episode recovery phase. They are not the defining diagnostic criteria for the syndrome itself. 3. **Clinical Pearls for NEET-PG:** * **The Classic Triad:** Hypersomnia, Hyperphagia (compulsive overeating), and Hypersexuality (disinhibition). * **Demographics:** Most common in adolescent males (Male:Female ratio is approx. 3:1). * **Course:** Episodes typically last days to weeks and recur several times a year. Between episodes, patients usually have normal sleep and mood. * **Management:** * *Acute episodes:* Supportive care. * *Prophylaxis:* **Lithium** is the most effective treatment for reducing the frequency and severity of episodes. Carbamazepine or Valproate are second-line options. * **Differential Diagnosis:** Must be distinguished from Kluver-Bucy Syndrome (which involves temporal lobe damage and lacks the periodic sleep episodes).

Q: Narcolepsy is characterized by excessive daytime sleepiness?

Excessive daytime sleepiness. **Explanation:** **Narcolepsy** is a chronic neurological disorder caused by the loss of orexin (hypocretin)-producing neurons in the hypothalamus, leading to an inability to regulate sleep-wake cycles. 1. **Why Option B is Correct:** **Excessive Daytime Sleepiness (EDS)** is the hallmark and usually the first symptom of narcolepsy. Patients experience "sleep attacks" where they fall asleep irresistibly during the day, regardless of the amount of sleep they had the previous night. 2. **Why Other Options are Incorrect:** * **Option A:** In narcolepsy, there is **decreased REM sleep latency**. Patients often enter REM sleep within 15 minutes of falling asleep (Sleep Onset REM Periods - SOREMPs), whereas normal REM latency is about 90 minutes. * **Option C:** While patients have EDS, their **total 24-hour sleep time** is usually normal or only slightly increased. Their sleep is fragmented and inefficient, rather than prolonged. * **Option D:** The **sleep architecture is highly abnormal**, characterized by sleep fragmentation and the intrusion of REM sleep components into wakefulness (e.g., cataplexy, sleep paralysis). **High-Yield Clinical Pearls for NEET-PG:** * **The Tetrad of Narcolepsy:** 1. Excessive Daytime Sleepiness, 2. Cataplexy (sudden loss of muscle tone triggered by emotions), 3. Sleep Paralysis, 4. Hypnagogic/Hypnopompic hallucinations. * **Pathophysiology:** Deficiency of **Hypocretin (Orexin)** in the CSF. * **Diagnosis:** Multiple Sleep Latency Test (MSLT) showing mean sleep latency <8 minutes and ≥2 SOREMPs. * **Treatment:** Modafinil/Armodafinil (first-line for EDS); Sodium Oxybate (for cataplexy and sleep fragmentation).

Q: All of the following are NREM sleep disorders except?

Nightmares. ### Explanation The correct answer is **Nightmares**. Sleep disorders are primarily classified based on the stage of sleep in which they occur: **NREM (Non-Rapid Eye Movement)** or **REM (Rapid Eye Movement)**. **1. Why Nightmares are the Correct Answer:** Nightmares are a **REM sleep parasomnia**. They typically occur during the later half of the night when REM periods are longer and more intense. Characteristics include vivid, frightening dreams from which the individual awakens fully alert with detailed recall of the dream content. Because muscle atonia is present during REM, there is usually no physical movement or screaming. **2. Analysis of NREM Disorders (Incorrect Options):** * **Somnambulism (Sleepwalking):** Occurs during Stage N3 (Deep/Slow-wave sleep). The individual is difficult to arouse and has no memory of the event. * **Pavor Nocturnus (Sleep Terrors):** Occurs during Stage N3. Characterized by sudden arousal, intense fear, autonomic hyperactivity (tachycardia, sweating), and screaming. Unlike nightmares, there is **no recall** of a dream. * **Somniloquy (Sleep Talking):** Can occur in both NREM and REM, but it is classically associated with NREM stages. **3. NEET-PG High-Yield Pearls:** * **Stage of Occurrence:** NREM parasomnias (Sleepwalking/Terrors) occur in the **first third** of the night (Stage N3). REM parasomnias (Nightmares) occur in the **last third**. * **Memory:** NREM disorders are characterized by **amnesia** for the episode; REM disorders (Nightmares) have **vivid recall**. * **Treatment:** For severe Sleepwalking or Sleep Terrors, **Benzodiazepines** (like Diazepam) are used because they suppress Stage N3 sleep. * **REM Sleep Behavior Disorder (RBD):** A condition where the normal muscle atonia of REM is lost, leading to "acting out" dreams; it is a strong predictor of future neurodegenerative diseases like Parkinson’s.

Question 1

Bruxism most commonly occurs during which phase of sleep?

Accepted Answer

NREM Stage II

Answer

REM sleep

Answer

NREM Stage I

Answer

NREM Stage III

Question 2

Kleine-Levin syndrome is characterized by which of the following?

Accepted Answer

Hypersomnia

Answer

Insomnia

Answer

Depression

Answer

Anxiety

Question 3

A person hears voices before falling asleep, with a history of falls and daytime sleep attacks. What is the probable diagnosis?

Accepted Answer

Narcolepsy

Answer

Schizophrenia

Answer

Delusion

Answer

Insomnia

Question 4

Narcolepsy is characterized by excessive daytime sleepiness?

Accepted Answer

Excessive daytime sleepiness

Answer

Increased REM sleep latency

Answer

Increased total sleep time

Answer

Normal sleep architecture

Question 5

All of the following are NREM sleep disorders except?

Accepted Answer

Nightmares

Answer

Somnambulism

Answer

Pavor nocturnus

Answer

Somniloquy

Sleep-Wake Disorders — MCQs

Sleep-Wake Disorders — MCQs

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