Sleep-Wake Disorders — MCQs

Sleep-Wake Disorders Indian Medical PG Practice Questions and MCQs

Question 21: Which of the following is true about narcolepsy?

A. Sudden onset of sleep
B. Presents in the second decade of life
C. Cataplexy
D. All of the above (Correct Answer)

Explanation: **Explanation:** Narcolepsy is a chronic neurological disorder characterized by the brain's inability to regulate sleep-wake cycles normally. It is primarily caused by the loss of **hypocretin (orexin)-producing neurons** in the hypothalamus. * **Sudden onset of sleep (Sleep Attacks):** Patients experience an irresistible urge to sleep during the day, often occurring at inappropriate times (e.g., while eating or talking). These "sleep attacks" typically lead into REM sleep almost immediately. * **Presents in the second decade:** The peak age of onset is typically during adolescence or young adulthood (around ages 15–25). * **Cataplexy:** This is the pathognomonic feature of Narcolepsy Type 1. It involves a sudden, temporary loss of muscle tone triggered by strong emotions like laughter, surprise, or anger, while consciousness remains preserved. Since all three features are characteristic of the disorder, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Tetrad of Narcolepsy:** 1. Excessive Daytime Sleepiness (EDS), 2. Cataplexy, 3. Sleep Paralysis, and 4. Hypnagogic/Hypnopompic hallucinations. 2. **Diagnosis:** Gold standard is the **Multiple Sleep Latency Test (MSLT)**, showing a mean sleep latency of <8 minutes and ≥2 Sleep Onset REM Periods (SOREMPs). 3. **CSF Findings:** Low levels of **Hypocretin-1** (Orexin-A). 4. **Treatment:** * For Daytime Sleepiness: **Modafinil** (First-line) or Armodafinil. * For Cataplexy: **Sodium Oxybate** (highly effective) or SSRIs/SNRIs (to suppress REM).

Question 22: Which investigation is used to diagnose sleep disturbances?

A. Polysomnography (Correct Answer)
B. Oximetry
C. Echocardiography
D. Orthography

Explanation: **Explanation:** **Polysomnography (PSG)** is the gold standard diagnostic test for sleep disorders. It is a comprehensive, multi-parametric study performed overnight in a sleep laboratory. It simultaneously monitors various physiological parameters, including brain activity (EEG), eye movements (EOG), muscle activity (EMG), heart rhythm (ECG), and respiratory functions. By integrating these data points, clinicians can identify sleep architecture (NREM/REM cycles), sleep latency, and specific disturbances like apnea or periodic limb movements. **Analysis of Incorrect Options:** * **Oximetry:** While pulse oximetry measures oxygen saturation and is used to screen for Obstructive Sleep Apnea (OSA), it cannot diagnose sleep architecture or other primary sleep disorders (like Narcolepsy or Insomnia) on its own. * **Echocardiography:** This is an ultrasound of the heart used to evaluate cardiac structure and function. While it may be used to check for complications of chronic OSA (like pulmonary hypertension), it is not a tool for diagnosing sleep disturbances. * **Orthography:** This refers to the conventional spelling system of a language and is entirely unrelated to medical diagnostics. **High-Yield Clinical Pearls for NEET-PG:** * **Multiple Sleep Latency Test (MSLT):** The gold standard for diagnosing **Narcolepsy** (shows decreased mean sleep latency and sleep-onset REM periods). * **Actigraphy:** A wearable device used to assess sleep-wake patterns over several days, often used for Circadian Rhythm Disorders. * **Sleep Hygiene:** The first-line management for Primary Insomnia. * **EEG Findings:** Remember that **Delta waves** are characteristic of Stage N3 (Deep Sleep), while **Sleep Spindles and K-complexes** define Stage N2.

Question 23: Pavor nocturnus is seen in which phase of the sleep cycle?

A. NREM S1
B. NREM S2
C. NREM S3 (Correct Answer)
D. REM SLEEP

Explanation: **Explanation:** **Pavor nocturnus**, commonly known as **Sleep Terrors**, is a type of arousal parasomnia. The correct answer is **NREM S3** (Slow Wave Sleep) because these episodes typically occur during the first third of the night when deep, delta-wave sleep is most prevalent. During this phase, the brain is in a state of "partial arousal," where the body becomes physically active while the mind remains in a deep sleep state. **Analysis of Options:** * **NREM S1 & S2 (Options A & B):** These are light stages of sleep. While sleep spindles and K-complexes occur in S2, they are not the primary stages for arousal disorders like sleep terrors. * **REM Sleep (Option D):** This is the stage associated with **Nightmares**. Unlike sleep terrors, nightmares occur during the later half of the night, involve vivid dream recall, and the individual wakes up fully alert. In REM sleep, there is muscle atonia, preventing the physical thrashing seen in Pavor nocturnus. **Clinical Pearls for NEET-PG:** * **Amnesia:** A hallmark of Pavor nocturnus is that the patient has **no memory** of the event the next morning. * **Autonomic Overactivity:** Episodes are characterized by a piercing scream, tachycardia, tachypnea, and diaphoresis. * **Management:** Usually involves reassurance as children often outgrow it. If severe, low-dose **Benzodiazepines** (like Diazepam) are used because they suppress Stage 3 sleep. * **Differential:** Remember, **Somnambulism** (Sleepwalking) also occurs in NREM S3.

Question 24: What is the drug of choice for treating narcolepsy?

A. Modafinil (Correct Answer)
B. Sildenafil
C. Disulfiram
D. Dexmedetomidine

Explanation: **Explanation:** **Narcolepsy** is a chronic neurological disorder characterized by excessive daytime sleepiness (EDS), cataplexy, and REM-sleep abnormalities. The primary goal of treatment is to manage debilitating daytime drowsiness. **Why Modafinil is the Correct Answer:** **Modafinil** is the **first-line drug of choice** for treating excessive daytime sleepiness in narcolepsy. It is a non-amphetamine wake-promoting agent. Its exact mechanism is not fully understood, but it is believed to inhibit dopamine reuptake and increase levels of hypothalamic **orexin (hypocretin)** and histamine. It is preferred over traditional stimulants because it has a lower risk of addiction, fewer sympathomimetic side effects (like tachycardia), and a lower potential for rebound hypersomnia. **Analysis of Incorrect Options:** * **B. Sildenafil:** A PDE-5 inhibitor used primarily for erectile dysfunction and pulmonary arterial hypertension; it has no role in sleep disorders. * **C. Disulfiram:** An aldehyde dehydrogenase inhibitor used as an aversive therapy in alcohol dependence (causes the Disulfiram-ethanol reaction). * **D. Dexmedetomidine:** A highly selective alpha-2 adrenergic agonist used for sedation in intensive care settings and during anesthesia; it promotes sleep rather than wakefulness. **High-Yield Clinical Pearls for NEET-PG:** * **Cataplexy Treatment:** While Modafinil treats sleepiness, **Sodium Oxybate** is the drug of choice for cataplexy (sudden loss of muscle tone). * **Pathophysiology:** Narcolepsy Type 1 is associated with a deficiency of **Hypocretin (Orexin)** in the cerebrospinal fluid. * **Classic Tetrad:** 1. Excessive daytime sleepiness, 2. Cataplexy, 3. Sleep paralysis, 4. Hypnagogic/Hypnopompic hallucinations. * **Diagnosis:** Confirmed via Polysomnography followed by a **Multiple Sleep Latency Test (MSLT)** showing a mean sleep latency <8 minutes and ≥2 REM periods.

Question 25: About narcolepsy, all are true except?

A. Associated with cataplexy
B. Equal in male and female
C. NREM (Correct Answer)
D. Hypnogogic hallucinations

Explanation: **Explanation:** Narcolepsy is a chronic neurological disorder characterized by the brain's inability to regulate sleep-wake cycles normally. The hallmark of narcolepsy is the **intrusion of REM (Rapid Eye Movement) sleep** into wakefulness. **Why Option C is the correct (False) statement:** In narcolepsy, patients typically enter **REM sleep directly** or within minutes of falling asleep (Sleep Onset REM Periods - SOREMPs). Normal sleep begins with NREM stages; however, narcoleptics bypass these stages. Therefore, narcolepsy is a disorder of **REM sleep**, not NREM sleep. **Analysis of other options:** * **Option A (Cataplexy):** This is a pathognomonic feature of Narcolepsy Type 1. It involves a sudden, temporary loss of muscle tone triggered by strong emotions (laughter, anger). It represents the intrusion of REM-associated muscle atonia into the waking state. * **Option B (Gender Distribution):** Epidemiological studies show that narcolepsy affects **males and females approximately equally**, with a slight, non-significant male preponderance in some studies. * **Option D (Hypnagogic Hallucinations):** These are vivid, often frightening sensory experiences occurring at the **onset of sleep**. Along with hypnopompic hallucinations (upon awakening) and sleep paralysis, they form the classic tetrad of narcolepsy. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Tetrad:** Excessive Daytime Sleepiness (EDS), Cataplexy, Sleep Paralysis, and Hypnagogic hallucinations. 2. **Etiology:** Strongly associated with the loss of **orexin (hypocretin)-producing neurons** in the lateral hypothalamus. 3. **Genetics:** Over 90% of patients with Narcolepsy Type 1 carry the **HLA-DQB1*0602** allele. 4. **Diagnosis:** Confirmed via Polysomnography followed by a **Multiple Sleep Latency Test (MSLT)** showing a mean sleep latency <8 minutes and ≥2 SOREMPs. 5. **Treatment:** Modafinil/Armodafinil (first-line for EDS); Sodium Oxybate (effective for cataplexy).

Question 26: Which of the following clinical findings is seen in parasomnia?

A. Nocturnal enuresis
B. Night terror
C. Nightmare
D. All of the above (Correct Answer)

Explanation: **Explanation:** Parasomnias are a category of sleep disorders characterized by **abnormal behavioral, experiential, or physiological events** occurring in association with sleep, specific sleep stages, or sleep-wake transitions. Unlike dyssomnias (which affect the quality, timing, or amount of sleep), parasomnias represent "things that go bump in the night." * **Night Terrors (Sleep Terrors):** These occur during **NREM Stage 3 (Slow Wave Sleep)**. The patient typically experiences intense autonomic arousal (tachycardia, sweating) and screaming but has **no memory** of the event (amnesia) upon waking. * **Nightmares:** These occur during **REM sleep**. Unlike night terrors, the patient awakens fully, is alert, and can **vividly recall** the frightening dream. * **Nocturnal Enuresis:** Involuntary voiding of urine during sleep (after age 5) is considered a parasomnia, typically occurring during the first third of the night in NREM sleep. Since all three conditions involve abnormal behaviors or experiences during sleep, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **NREM Parasomnias:** Include Sleepwalking (Somnambulism) and Sleep Terrors. They occur in the first third of the night. * **REM Parasomnias:** Include Nightmares and REM Sleep Behavior Disorder (RBD). RBD is strongly associated with future **alpha-synucleinopathies** (e.g., Parkinson’s disease). * **Drug of Choice:** Low-dose **Benzodiazepines** (like Diazepam or Clonazepam) are often used to treat severe sleep terrors or somnambulism as they suppress Stage 3 and REM sleep. * **Age Factor:** Most childhood parasomnias are physiological and tend to resolve spontaneously with CNS maturation.

Question 27: Somnambulism is:

A. REM sleep disorder
B. Midway between sleeping and walking
C. Type of automatism
D. NREM sleep disorder (Correct Answer)

Explanation: **Explanation:** **Somnambulism (Sleepwalking)** is a parasomnia characterized by complex motor behaviors initiated during sleep. The correct answer is **D (NREM sleep disorder)** because somnambulism occurs during **Stage N3 (Slow Wave Sleep)** of Non-Rapid Eye Movement (NREM) sleep, typically during the first third of the night. * **Why Option D is Correct:** During NREM Stage 3, the brain is in a state of deep sleep, but the body maintains muscle tone. In somnambulism, there is a partial arousal where the motor systems are activated while the cortical regions responsible for conscious awareness remain "asleep." * **Why Option A is Incorrect:** REM sleep is characterized by muscle atonia (paralysis). Disorders involving movement during REM (like REM Sleep Behavior Disorder) are distinct and usually involve acting out vivid dreams, occurring later in the night. * **Why Option B is Incorrect:** While it may appear as a "midway" state, this is a layperson’s description and not a medical classification. * **Why Option C is Incorrect:** Automatism refers to involuntary behaviors performed without conscious intent (often seen in epilepsy or dissociative states). While sleepwalking involves automatic movements, it is specifically classified as a sleep disorder (parasomnia), not a primary automatism. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Occurs in the first 1/3rd of the night (NREM). * **Memory:** There is typically **complete amnesia** for the episode. * **Management:** The primary goal is safety and injury prevention. Pharmacotherapy (Benzodiazepines like Diazepam) is used only if episodes are frequent or dangerous. * **Associated Disorders:** Other NREM parasomnias include **Sleep Terrors** (Pavor Nocturnus) and Confusional Arousals.

Question 28: Which of the following is NOT true about narcolepsy?

A. Sleep attacks
B. Long duration (>3 hours) of sleep (Correct Answer)
C. Cataplexy
D. Presents in the second decade

Explanation: **Explanation** Narcolepsy is a chronic neurological disorder characterized by the brain's inability to regulate sleep-wake cycles normally, primarily due to the loss of **hypocretin (orexin)** producing neurons in the hypothalamus. **Why Option B is the Correct Answer:** Narcolepsy is characterized by **short, refreshing naps**. A typical sleep attack lasts anywhere from a few minutes to **20–30 minutes**. Patients usually wake up feeling refreshed but may fall asleep again a few hours later. Therefore, a "long duration (>3 hours) of sleep" is inconsistent with the clinical presentation of narcoleptic sleep attacks. **Analysis of Other Options:** * **A. Sleep attacks:** These are sudden, irresistible urges to sleep that can occur at any time (e.g., while eating or talking). This is the hallmark of the disease. * **C. Cataplexy:** This is a sudden, temporary loss of muscle tone triggered by strong emotions (laughter, anger). It is the most specific symptom of Narcolepsy Type 1. * **D. Presents in the second decade:** The peak age of onset for narcolepsy is bimodal, but it most commonly first manifests during **adolescence (the second decade)**, typically between ages 15 and 25. **High-Yield Clinical Pearls for NEET-PG:** * **The Tetrad of Narcolepsy:** 1. Excessive Daytime Sleepiness (EDS), 2. Cataplexy, 3. Sleep Paralysis, 4. Hypnagogic/Hypnopompic hallucinations. * **Pathophysiology:** Deficiency of **Hypocretin (Orexin)** in the CSF. * **Sleep Architecture:** Characterized by **Sleep-Onset REM (SOREM)**; patients enter REM sleep within 15 minutes of sleep onset. * **Diagnosis:** Gold standard is the **Multiple Sleep Latency Test (MSLT)** showing mean sleep latency <8 minutes and ≥2 SOREMs. * **Treatment:** **Modafinil** is the first-line treatment for daytime sleepiness; **Sodium Oxybate** is used for cataplexy.

Question 29: Which of the following is a component of good sleep hygiene?

A. Arise at the same time daily (Correct Answer)
B. Eat larger meals near bedtime
C. Take daytime naps as needed
D. Exercise in the evening

Explanation: **Explanation:** Sleep hygiene refers to a set of behavioral and environmental practices designed to promote better sleep quality and daytime alertness. It is the first-line non-pharmacological intervention for Insomnia. **Correct Option (A): Arise at the same time daily** The cornerstone of sleep hygiene is maintaining a consistent **circadian rhythm**. Waking up at the same time every day (including weekends) stabilizes the body’s internal clock and regulates the sleep-wake cycle. This ensures that the "sleep drive" (adenosine buildup) begins at a predictable time, making it easier to fall asleep the following night. **Why Incorrect Options are Wrong:** * **B. Eat larger meals near bedtime:** Heavy, spicy, or sugary meals late at night can cause gastrointestinal discomfort or acid reflux, which fragments sleep. A light snack is acceptable, but large meals should be avoided 2–3 hours before bed. * **C. Take daytime naps as needed:** Napping, especially late in the afternoon, reduces the "homeostatic sleep debt" required to initiate sleep at night, leading to difficulty falling asleep (increased sleep latency). * **D. Exercise in the evening:** While regular exercise improves sleep, vigorous physical activity within 3–4 hours of bedtime increases core body temperature and stimulates the sympathetic nervous system, both of which interfere with sleep onset. **High-Yield Clinical Pearls for NEET-PG:** * **Stimulus Control Therapy:** The bed should be used **only** for sleep and sex (no reading, eating, or watching TV). * **The 20-Minute Rule:** If unable to sleep within 20 minutes, the patient should leave the bedroom and perform a quiet activity in dim light until sleepy. * **Substances:** Avoid caffeine (6+ hours before bed), nicotine (stimulant), and alcohol (causes sleep fragmentation and worsens apnea). * **Environment:** The bedroom should be cool, dark, and quiet.

Question 30: Which of the following disorders is not typically associated with the REM stage of sleep?

A. Nightmares
B. Narcolepsy
C. Somnambulism (Correct Answer)
D. Sleep apnea

Explanation: ### Explanation The correct answer is **Somnambulism (Sleepwalking)**. **1. Why Somnambulism is the correct answer:** Somnambulism is a **NREM (Non-Rapid Eye Movement) Parasomnia**. It typically occurs during **Stage N3 (Slow Wave Sleep)**, which is the deepest stage of NREM sleep. Because it occurs during NREM, the patient usually has no memory of the event (amnestic) and lacks the muscle atonia (paralysis) characteristic of REM sleep, allowing them to perform complex motor activities like walking. **2. Analysis of Incorrect Options:** * **Nightmares (Option A):** These are **REM Parasomnias**. They occur during the later half of the night when REM density is highest. Unlike sleep terrors (NREM), patients can usually recall the vivid, frightening dream content upon waking. * **Narcolepsy (Option B):** This is characterized by the **intrusion of REM sleep** into wakefulness. Key features like cataplexy (sudden loss of muscle tone) and sleep paralysis are direct manifestations of REM-related muscle atonia occurring at inappropriate times. * **Sleep Apnea (Option C):** While it can occur in NREM, Obstructive Sleep Apnea (OSA) is typically **most severe during REM sleep**. This is because the generalized muscle atonia of REM further reduces upper airway muscle tone, leading to increased frequency and duration of apneic events. **3. NEET-PG High-Yield Pearls:** * **NREM Parasomnias (Stage N3):** Sleepwalking (Somnambulism), Sleep Terrors (Pavor Nocturnus), and Confusional Arousals. * **REM Parasomnias:** Nightmares and REM Sleep Behavior Disorder (RBD). * **RBD Clinical Link:** REM Sleep Behavior Disorder (acting out dreams due to loss of muscle atonia) is a strong predictor of future **Alpha-synucleinopathies** like Parkinson’s disease or Lewy Body Dementia. * **Drug of Choice:** Benzodiazepines (like Clonazepam) are often used for severe NREM parasomnias as they suppress Stage N3 sleep.

Practice by Chapter

Normal Sleep Physiology

Practice Questions

Insomnia Disorder

Practice Questions

Hypersomnolence Disorders

Practice Questions

Narcolepsy

Practice Questions

Breathing-Related Sleep Disorders

Practice Questions

Circadian Rhythm Sleep-Wake Disorders

Practice Questions

Parasomnias

Practice Questions

Sleep-Related Movement Disorders

Practice Questions

Sleep Disorders in Psychiatric Conditions

Practice Questions

Pharmacotherapy for Sleep Disorders

Practice Questions

Cognitive-Behavioral Therapy for Insomnia

Practice Questions

Sleep Hygiene and Other Non-pharmacological Approaches

Practice Questions

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