Sleep-Wake Disorders Practice Questions

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

Somnambulism. ### 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.

Q: A middle-aged man complains of lack of sleep during the night. Which of the following can be used to determine the duration he is truly asleep or awake?

Actigraphy. **Explanation:** **Actigraphy** is the correct answer because it is a non-invasive method used to monitor human rest/activity cycles. It involves wearing a small, watch-like device (actigraph) on the wrist that contains an accelerometer to record movement. In sleep medicine, specialized algorithms translate these movement patterns into data regarding sleep latency, total sleep time, and wakefulness after sleep onset. It is particularly useful for assessing insomnia and circadian rhythm disorders over several days or weeks in a natural home environment. **Analysis of Incorrect Options:** * **Barograph:** An instrument used in meteorology to continuously record atmospheric pressure. It has no application in monitoring human sleep. * **Kymograph:** A device used to record temporal variations in physiological processes (like muscle contractions or blood pressure) on a rotating drum. While historically significant in physiology labs, it is not used for sleep duration monitoring. * **Plethysmography:** A technique used to measure changes in volume within an organ or the whole body (e.g., lung volumes or blood flow in limbs). While "Penile Plethysmography" can be used to monitor erections during REM sleep, it does not determine the overall duration of being awake or asleep. **Clinical Pearls for NEET-PG:** * **Gold Standard:** Polysomnography (PSG) remains the gold standard for diagnosing most sleep disorders (like OSA), but **Actigraphy** is preferred for long-term longitudinal monitoring of sleep-wake patterns. * **Sleep Hygiene:** The first-line management for primary insomnia. * **Drug of Choice:** Melatonin agonists (Ramelteon) or Z-drugs (Zolpidem) are commonly used for short-term pharmacological management of insomnia.

Q: The hypocretin system plays a critical role in which of the following disorders?

Narcolepsy. **Explanation:** **Correct Option: D. Narcolepsy** Hypocretin (also known as **orexin**) is a neuropeptide produced in the lateral hypothalamus that regulates wakefulness and arousal. The pathophysiology of **Narcolepsy Type 1** (narcolepsy with cataplexy) is primarily characterized by the selective autoimmune destruction of these hypocretin-producing neurons. This deficiency leads to an inability to maintain stable wakefulness and the intrusion of REM sleep phenomena into wakefulness (e.g., cataplexy, sleep paralysis). Diagnosis is often confirmed by low levels of Hypocretin-1 in the cerebrospinal fluid (CSF). **Incorrect Options:** * **A. Insomnia:** While orexin receptor antagonists (e.g., Suvorexant) are used to treat insomnia by blocking wakefulness, the primary etiology of insomnia is not a dysfunction of the hypocretin system itself, but rather hyperarousal. * **B. Depression:** Depression is primarily linked to the monoamine hypothesis (deficits in Serotonin, Norepinephrine, and Dopamine). While sleep disturbances occur in depression, hypocretin is not the core neurobiological driver. * **C. Obsessive-compulsive disorder (OCD):** OCD is associated with dysregulation in the Cortico-Striato-Thalamo-Cortical (CSTC) circuits and serotonin imbalance, with no established link to the hypocretin system. **High-Yield Clinical Pearls for NEET-PG:** * **Narcolepsy Tetrad:** Excessive daytime sleepiness, Cataplexy (sudden loss of muscle tone triggered by emotion), Sleep paralysis, and Hypnagogic/Hypnopompic hallucinations. * **HLA Association:** Strong association with **HLA-DQB1*0602**. * **Treatment:** Modafinil is the first-line treatment for daytime sleepiness; Sodium Oxybate is used for cataplexy. * **CSF Findings:** Hypocretin-1 levels **<110 pg/mL** are diagnostic for Narcolepsy Type 1.

Q: Which of the following is NOT a symptom of narcolepsy?

Catalepsy. **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 orexin (hypocretin)-producing neurons in the hypothalamus. **Why Catalepsy is the correct answer:** **Catalepsy** is a state of muscular rigidity and fixed posture regardless of external stimuli, often associated with schizophrenia (catatonia), Parkinsonism, or epilepsy. It is frequently confused with **Cataplexy**, but they are distinct clinical entities. Catalepsy involves "waxy flexibility," whereas narcolepsy involves sudden loss of muscle tone. **Analysis of Incorrect Options (Symptoms of Narcolepsy):** * **Daytime Sleepiness:** This is the most common and often the first symptom. Patients experience "sleep attacks" that can occur at any time, even during active tasks. * **Cataplexy:** This is the pathognomonic sign of Narcolepsy Type 1. It involves a sudden, bilateral loss of muscle tone triggered by strong emotions (laughter, surprise, or anger) while the patient remains conscious. * **Hypnagogic Hallucinations:** These are vivid, often frightening sensory experiences that occur at the transition from wakefulness to sleep. (Note: *Hypnopompic* hallucinations occur upon awakening). **High-Yield Clinical Pearls for NEET-PG:** * **The Tetrad of Narcolepsy:** 1. Excessive Daytime Sleepiness, 2. Cataplexy, 3. Sleep Paralysis, 4. Hypnagogic Hallucinations. * **Sleep Architecture:** Narcolepsy is characterized by **shortened REM latency** (Sleep-Onset REM periods or SOREMPs). * **Diagnosis:** Gold standard is the **Multiple Sleep Latency Test (MSLT)** showing a mean sleep latency <8 minutes. * **Treatment:** Modafinil/Armodafinil (first-line for sleepiness); Sodium Oxybate (effective for both sleepiness and cataplexy).

Q: A person laughs at a joke, then suddenly loses the tone of all muscles. What is the diagnosis?

Cataplexy. ### Explanation **Correct Answer: A. Cataplexy** **Why it is correct:** Cataplexy is a pathognomonic feature of **Narcolepsy Type 1**. It is defined as a sudden, brief loss of voluntary muscle tone (bilateral) while the patient remains fully conscious. Crucially, these episodes are triggered by **strong emotions**, most commonly laughter, surprise, or anger. Physiologically, it represents an intrusion of REM sleep muscle atonia into wakefulness, often due to a deficiency of the neurotransmitter **Hypocretin (Orexin)** in the hypothalamus. **Why the other options are incorrect:** * **B. Catalepsy:** This is a state of "waxy flexibility" or rigid body posture often seen in **Catatonia** or schizophrenia. Unlike cataplexy, there is no sudden loss of tone; instead, the patient maintains a position in which they are placed. * **C. Sleep attack:** This refers to the sudden, irresistible urge to sleep during the day. While it is a core symptom of narcolepsy, it involves a loss of consciousness (falling asleep), whereas cataplexy involves only a loss of muscle tone with preserved consciousness. * **D. Sleep paralysis:** This is the inability to move or speak while falling asleep (hypnagogic) or waking up (hypnopompic). While common in narcolepsy, it is not triggered by emotional stimuli like laughter. **High-Yield Clinical Pearls for NEET-PG:** * **Narcolepsy Tetrad:** 1. Excessive Daytime Sleepiness (EDS), 2. Cataplexy, 3. Sleep Paralysis, 4. Hypnagogic/Hypnopompic hallucinations. * **Gold Standard Diagnosis:** Polysomnography followed by **Multiple Sleep Latency Test (MSLT)** showing mean sleep latency <8 mins and ≥2 Sleep Onset REM periods (SOREMPs). * **Treatment:** Modafinil (first-line for EDS); **Sodium Oxybate** (highly effective for cataplexy).

Q: Bruxism is:

Grinding of teeth during sleep. **Explanation:** **Bruxism** is defined as the involuntary grinding, gnashing, or clenching of teeth. When it occurs during sleep, it is classified as a **Sleep-Related Movement Disorder** (ICSD-3). It typically occurs during NREM Stage N1 and N2 sleep. Clinically, it can lead to dental attrition, hypertrophy of the masseter muscle, and temporomandibular joint (TMJ) pain. **Analysis of Options:** * **Option A (Walking during sleep):** This refers to **Somnambulism**. It is a parasomnia that occurs during Stage N3 (Slow Wave Sleep). * **Option B (Nocturnal enuresis):** This is involuntary voiding of urine during sleep in a child old enough to have bladder control (usually >5 years). It also typically occurs during N3 sleep. * **Option D (Sleep apnea):** This is a sleep-related breathing disorder characterized by repetitive pauses in breathing during sleep due to airway obstruction (Obstructive) or lack of respiratory effort (Central). **High-Yield Clinical Pearls for NEET-PG:** * **Treatment:** The primary management for sleep bruxism involves **stress reduction** and the use of **mouth guards (occlusal splints)** to prevent dental damage. In severe cases, Benzodiazepines or Botox injections into the masseter may be considered. * **Associated Factors:** It is often associated with stress, anxiety, and certain substances (SSRIs, stimulants, or alcohol). * **Stages of Sleep:** Remember that most Parasomnias (Sleepwalking, Sleep Terrors) occur in **N3**, while Nightmares occur during **REM** sleep. Bruxism is unique as it is most frequent in **Light NREM (N1/N2)**.

Q: What is the treatment of choice in Sleep Apnea Syndrome?

Continuous positive pressure ventilation.. **Explanation:** **Sleep Apnea Syndrome (SAS)**, specifically Obstructive Sleep Apnea (OSA), is characterized by repetitive episodes of partial or complete upper airway obstruction during sleep. This leads to hypoxia, hypercapnia, and frequent micro-arousals, resulting in excessive daytime sleepiness. **Why Option A is correct:** **Continuous Positive Airway Pressure (CPAP)** is the gold standard and treatment of choice for OSA. It acts as a "pneumatic splint," providing a constant stream of pressurized air that keeps the upper airway patent throughout the respiratory cycle, preventing collapse and normalizing sleep architecture. **Why the other options are incorrect:** * **Sedatives (B):** These are strictly **contraindicated**. Sedatives (like Benzodiazepines) decrease upper airway muscle tone and suppress the arousal response to hypoxia, significantly worsening the apnea and increasing the risk of respiratory failure. * **Antidepressants (C):** While some (like Protriptyline) were historically used to reduce REM sleep (where apnea is worst), they are not first-line and are far less effective than CPAP. * **Antiepileptics (D):** These have no established role in the primary treatment of sleep apnea. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Overnight **Polysomnography** (PSG). * **Severity Marker:** Apnea-Hypopnea Index (AHI). AHI >5 with symptoms or AHI >15 regardless of symptoms confirms the diagnosis. * **Classic Triad:** Loud snoring, witnessed apneas, and excessive daytime sleepiness. * **Associated Risks:** Hypertension (most common), Right-sided heart failure (Cor Pulmonale), and increased risk of motor vehicle accidents. * **Surgical Option:** Uvulopalatopharyngoplasty (UPPP) may be considered if CPAP fails or in cases of anatomical obstruction.

Q: A 7-year-old girl is reported by the parents as waking up in the night screaming, and she sits up in bed frightened. She does not respond to questions and after 2 or 3 minutes she goes back to sleep. She has no memory of these events the following morning. Which of the following is the most likely diagnosis?

Sleep terrors. ***Sleep terrors*** - **Sleep terrors** are characterized by abrupt awakenings, intense fear and screaming, autonomic arousal, and unresponsiveness, typically occurring during **NREM sleep** in the first third of the night. - The child will have **no memory** of the event the next morning, which is a key diagnostic feature, and they often return to sleep quickly afterward. *Nightmare* - **Nightmares** occur during **REM sleep**, usually in the latter half of the night, and the individual can often recall vivid and frightening details upon waking. - Unlike sleep terrors, individuals experiencing nightmares are typically **responsive to comfort** and fully alert after waking. *Narcolepsy* - **Narcolepsy** is a chronic neurological condition characterized by overwhelming daytime sleepiness and irresistible urges to sleep, often accompanied by **cataplexy**. - It does not involve nocturnal screaming episodes or unresponsiveness followed by a quick return to sleep with no memory. *Nocturnal seizures* - **Nocturnal seizures** can cause nocturnal awakenings with confusion or unusual behaviors, but they often involve **stereotyped movements**, sometimes with motor manifestations or post-ictal confusion that lasts longer than a few minutes. - While there might be no memory of the event, the screaming and frightened demeanor without typical seizure activity make sleep terrors a more likely diagnosis.

Question 1

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

Accepted Answer

Somnambulism

Answer

Nightmares

Answer

Narcolepsy

Answer

Sleep apnea

Question 2

A middle-aged man complains of lack of sleep during the night. Which of the following can be used to determine the duration he is truly asleep or awake?

Accepted Answer

Actigraphy

Answer

Barograph

Answer

Kymograph

Answer

Plethysmography

Question 3

Cataplexy refers to:

Accepted Answer

Sudden weakness or loss of muscle tone without loss of consciousness, often elicited by emotion

Answer

Hallucinations at sleep onset (hypnagogic hallucinations) or upon awakening

Answer

Muscle paralysis upon awakening

Answer

Muscle paralysis after sleeping

Question 4

The hypocretin system plays a critical role in which of the following disorders?

Accepted Answer

Narcolepsy

Answer

Insomnia

Answer

Depression

Answer

Obsessive-compulsive disorder

Question 5

Which of the following is NOT a symptom of narcolepsy?

Accepted Answer

Catalepsy

Answer

Cataplexy

Answer

Daytime sleepiness

Answer

Hypnagogic hallucinations

Question 6

A 25-year-old man presents with a long-standing complaint of excessive daytime sleepiness, leading to multiple instances of falling asleep at work. He has no significant past medical history and is not on any sedative medications. Physical examination reveals a normal neurological assessment. Which of the following symptoms might he also complain about?

Accepted Answer

Automatic behaviors

Answer

Excessive snoring

Answer

Restless sleep

Answer

Paresthesia

Question 7

A person laughs at a joke, then suddenly loses the tone of all muscles. What is the diagnosis?

Accepted Answer

Cataplexy

Answer

Catalepsy

Answer

Sleep attack

Answer

Sleep paralysis

Question 8

Bruxism is:

Accepted Answer

Grinding of teeth during sleep

Answer

Walking during sleep

Answer

Nocturnal enuresis

Answer

Sleep apnea

Question 9

What is the treatment of choice in Sleep Apnea Syndrome?

Accepted Answer

Continuous positive pressure ventilation.

Answer

Sedatives.

Answer

Antidepressants.

Answer

Antiepileptics.

Question 10

A 7-year-old girl is reported by the parents as waking up in the night screaming, and she sits up in bed frightened. She does not respond to questions and after 2 or 3 minutes she goes back to sleep. She has no memory of these events the following morning. Which of the following is the most likely diagnosis?

Accepted Answer

Sleep terrors

Answer

Nightmare

Answer

Narcolepsy

Answer

Nocturnal seizures

Sleep-Wake Disorders — MCQs

Sleep-Wake Disorders — MCQs

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