Sleep and Wakefulness — MCQs
Child wakes up at night sweating and terrified, does not remember the episode - diagnosis?
A 42-year-old female executive is referred to the sleep clinic with jaw pain. She complains that after she arrives home at night around 10 pm she frequently drinks 3-4 gin and tonics to help quiet her mind.’ She wakes up the next morning around 3am to read the international stock market news, at which point she states her teeth ache an unbearable amount. A study is performed on the patient and it is noted that she grinds her teeth and mutters during roughly half of her sleep. Which of the following would you expect to see on her EEG and at which stage of sleep would you expect her jaw pain to be caused?
During polysomnography, which stage of sleep is represented by the marked areas when observing the following wave patterns? EOG (Electrooculography) EEG (Electroencephalography) EMG (Electromyography)
In narcolepsy, the polysomnographic recording typically shows which of the following patterns?
A polysomnography is performed on a patient. Based on the provided EEG, EOG, and EMG findings, which stage of sleep is indicated? (Image: img-182.jpeg)
What do motor evoked potentials primarily assess?
Berger waves (alpha waves) of EEG have a rhythm of how many Hz?
Alpha wave on EEG represents -
The blood levels of hormones are elevated during exercise and sleep as shown. Which hormone would exhibit this diurnal pattern?
Which wave is seen in the given EEG recording?
Sleep and Wakefulness Indian Medical PG Practice Questions and MCQs
Question 1: Child wakes up at night sweating and terrified, does not remember the episode - diagnosis?
- A. Narcolepsy
- B. Nightmares
- C. Night terrors (Correct Answer)
- D. Somnambulism
Explanation: ***Night terrors*** - **Night terrors** are characterized by partial arousals from **deep non-REM sleep** (typically N3 stage), often accompanied by loud screams, thrashing, and autonomic symptoms like sweating and tachycardia. - The child is very difficult to awaken or comfort during an episode and, crucially, has **no memory of the event** upon waking, which differentiates it from nightmares. *Narcolepsy* - **Narcolepsy** is a chronic neurological condition characterized by overwhelming daytime **sleepiness** and sudden attacks of sleep. - It often involves **cataplexy** (sudden loss of muscle tone triggered by strong emotions) and **hypnagogic/hypnopompic hallucinations**, which are not described. *Nightmares* - **Nightmares** are vivid, frightening dreams that occur during **REM sleep** and typically result in full awakening and the ability to **recall the dream content**. - While they cause fear and distress, episodes do not usually involve the terrified unresponsiveness or lack of recall seen in night terrors. *Somnambulism* - **Somnambulism** (sleepwalking) occurs during **deep non-REM sleep**, and affected individuals may perform complex actions while partially aroused. - While there is amnesia for the event, prominent features like **sweating and intense terror** are not typical components of sleepwalking.
Question 2: A 42-year-old female executive is referred to the sleep clinic with jaw pain. She complains that after she arrives home at night around 10 pm she frequently drinks 3-4 gin and tonics to help quiet her mind.’ She wakes up the next morning around 3am to read the international stock market news, at which point she states her teeth ache an unbearable amount. A study is performed on the patient and it is noted that she grinds her teeth and mutters during roughly half of her sleep. Which of the following would you expect to see on her EEG and at which stage of sleep would you expect her jaw pain to be caused?
- A. Alpha waves, N2
- B. Beta waves, N3
- C. Delta waves, N3
- D. Sleep spindles, N2 (Correct Answer)
Explanation: ***Sleep spindles, N2*** - The patient's presentation of teeth grinding (**bruxism**) and muttering during sleep, along with jaw pain, is characteristic of **parasomnias**, which often occur during **stage N2 sleep**. - **Sleep spindles** and **K-complexes** are defining EEG features of **N2 sleep**, indicating that the sleep study would likely show these patterns. *Alpha waves, N2* - **Alpha waves** are characteristic of a **relaxed, awake state** or the early stages of falling asleep (N1), not N2 sleep. - While the patient has jaw pain, its cause is linked to sleep behaviors occurring in more advanced sleep stages than N1. *Beta waves, N3* - **Beta waves** are typically seen during **active wakefulness** and **REM sleep**, not deep N3 sleep. - **N3 sleep** (slow-wave sleep) is characterized by **delta waves**, not beta waves. *Delta waves, N3* - Although **delta waves** are indeed characteristic of **N3 sleep** (deep sleep), the patient's symptoms of teeth grinding and muttering are more commonly associated with **N2 sleep** or arousal disorders, not typically the deepest stage of sleep. - Bruxism and muttering are generally not prominent features of undisturbed N3 sleep.
Question 3: During polysomnography, which stage of sleep is represented by the marked areas when observing the following wave patterns? EOG (Electrooculography) EEG (Electroencephalography) EMG (Electromyography)
- A. REM sleep
- B. NREM I sleep (Correct Answer)
- C. NREM II sleep
- D. NREM III sleep
Explanation: ***NREM I sleep*** - This stage is characterized by a transition from wakefulness to sleep, identifiable by the appearance of **slow eye movements** in the EOG and a reduction in EEG frequency with the presence of **theta waves**. - The EMG shows a decrease in muscle tone but without the complete atonia seen in REM sleep. *REM sleep* - **Rapid eye movements** are characteristic in the EOG, and the EEG shows **low-amplitude, mixed-frequency waves** similar to wakefulness. - The EMG would display profound muscle atonia, which is not evident in the provided tracing. *NREM II sleep* - This stage is marked by the presence of **sleep spindles** and **K-complexes** in the EEG, which are absent in the marked area. - Eye movements are generally absent, and muscle activity continues to be low. *NREM III sleep* - This is the deepest stage of sleep, characterized by **high-amplitude, slow-delta waves** (20-50% of the epoch) in the EEG. - Eye movements are typically absent, and muscle tone is very low but not completely absent.
Question 4: In narcolepsy, the polysomnographic recording typically shows which of the following patterns?
- A. REM intrusion during inappropriate periods (Correct Answer)
- B. An absence of REM sleep in midcycle
- C. Extreme muscular relaxation
- D. Spike-and-wave EEG recording
Explanation: ***REM intrusion during inappropriate periods*** - In narcolepsy, the hallmark polysomnographic finding is **sleep-onset REM periods (SOREMPs)** - the occurrence of REM sleep within 15 minutes of sleep onset. - The **Multiple Sleep Latency Test (MSLT)** in narcolepsy typically shows **≥2 SOREMPs** along with a mean sleep latency of ≤8 minutes. - Clinically, this **REM sleep intrusion** manifests as **sudden, irresistible sleep attacks** during the day, **cataplexy** (sudden muscle weakness triggered by strong emotions), **sleep paralysis**, and **hypnagogic/hypnopompic hallucinations**. - These represent features of REM sleep (muscle atonia, dreams) occurring at inappropriate times. *An absence of REM sleep in midcycle* - This statement is incorrect as narcolepsy is characterized by an **abnormal presence and early onset of REM sleep**, not its absence. - Individuals with narcolepsy enter REM sleep much faster than normal (often within minutes rather than the typical 90 minutes). *Extreme muscular relaxation* - While **cataplexy** (present in Type 1 narcolepsy) involves sudden loss of muscle tone due to REM-related atonia during wakefulness, this is a clinical symptom rather than a continuous polysomnographic finding. - Polysomnography focuses on **sleep architecture** and the timing of **REM sleep onset**, not general muscle relaxation patterns. *Spike-and-wave EEG recording* - **Spike-and-wave patterns** on EEG are characteristic of **absence seizures** (a form of epilepsy), not narcolepsy. - Narcolepsy is a primary **sleep disorder** with distinct polysomnographic features related to **REM sleep dysregulation**, not epileptiform activity.
Question 5: A polysomnography is performed on a patient. Based on the provided EEG, EOG, and EMG findings, which stage of sleep is indicated? (Image: img-182.jpeg)
- A. NREM 1
- B. NREM 2 (Correct Answer)
- C. NREM 3
- D. REM
Explanation: ***NREM 2*** - This stage is characterized by the presence of **sleep spindles** (bursts of brain activity) and **K-complexes** (large, slow waves) on the EEG. - The EOG typically shows **no significant eye movement**, and the EMG registers **lower muscle tension** compared to wakefulness or NREM 1. *NREM 1* - This initial stage of sleep is marked by the appearance of **theta waves** on the EEG and a reduction in alpha wave activity. - The EOG often shows **slow, rolling eye movements**, and the EMG indicates slightly **reduced muscle tone** compared to the wake state. *NREM 3* - Often referred to as **deep sleep** or slow-wave sleep, this stage is characterized by a significant presence of **delta waves** (high amplitude, low frequency) on the EEG, comprising 20-50% of the epoch. - Eye movements are **minimal or absent** on EOG, and muscle tension on EMG is **lower** than in NREM 2 but still present. *REM* - This stage is distinguished by **rapid eye movements** (REMs) observed on the EOG and a characteristic **sawtooth pattern** or low-voltage, mixed-frequency activity on the EEG. - A key feature of REM sleep is **atonia** (paralysis of skeletal muscles), resulting in the **lowest muscle tone** on the EMG, often appearing as a flat line.
Question 6: What do motor evoked potentials primarily assess?
- A. Central motor pathways (Correct Answer)
- B. Both central and peripheral motor pathways
- C. Muscle regeneration
- D. Peripheral motor pathways
Explanation: ***Central motor pathways*** - **Motor evoked potentials (MEPs)** are generated by electrical or magnetic stimulation of the **motor cortex** and primarily assess the integrity of **central motor pathways**, specifically the **corticospinal tracts**. - MEPs are the **gold standard** for monitoring **upper motor neuron** function during neurosurgical and spinal procedures. - The technique is most sensitive to dysfunction in the **brain and spinal cord** (central nervous system), making this their primary clinical utility. *Peripheral motor pathways* - While MEPs do eventually activate peripheral motor neurons to produce muscle responses, they are **not the primary tool** for assessing peripheral pathways. - **Nerve conduction studies (NCS)** and **electromyography (EMG)** are direct and more specific measures for evaluating peripheral motor nerve function. *Both central and peripheral motor pathways* - Although MEPs provide information about the entire motor pathway from cortex to muscle, their **primary diagnostic strength and clinical application** is in detecting dysfunction within the **central nervous system**. - The latency and amplitude of MEPs are most sensitive to **conduction abnormalities along the corticospinal tract**, not peripheral nerves. *Muscle regeneration* - MEPs do **not assess muscle regeneration** or intrinsic muscle health. - **Electromyography (EMG)** with needle examination and **muscle biopsy** are the appropriate methods to evaluate muscle regeneration and myopathic processes.
Question 7: Berger waves (alpha waves) of EEG have a rhythm of how many Hz?
- A. 0-4 Hz
- B. 4-7 Hz
- C. 8-13 Hz (Correct Answer)
- D. 13-30 Hz
Explanation: ***8-13 Hz*** - **Berger waves**, also known as **alpha waves**, are defined by their frequency range of **8 to 13 Hz** in the electroencephalogram (EEG). - These waves are typically observed when a person is in a relaxed, awake state with their eyes closed. *0-4 Hz* - This frequency range corresponds to **delta waves**, which are characteristic of deep sleep and certain brain pathologies. - Delta waves are much slower and have higher amplitude compared to alpha waves. *4-7 Hz* - This frequency range is associated with **theta waves**, commonly seen during light sleep, drowsiness, and some meditative states. - Theta waves are slower than alpha waves and indicate a state of reduced alertness. *13-30 Hz* - This frequency range represents **beta waves**, which are associated with active thinking, problem-solving, and alertness with open eyes. - Beta waves are faster and typically have lower amplitude than alpha waves.
Question 8: Alpha wave on EEG represents -
- A. Awake and fully alert
- B. Awake with eyes open
- C. Awake with eyes closed with mind wandering (Correct Answer)
- D. Deep sleep
Explanation: ***Awake with eyes closed with mind wandering*** - **Alpha waves** are characteristic of a relaxed, wakeful state when the eyes are closed and the mind is not actively focusing on a task. - They typically have a frequency range of 8-13 Hz and are most prominent over the **occipital lobe**. *Awake and fully alert* - This state is primarily associated with **beta waves** (13-30 Hz) due to active mental engagement and processing. - Alpha waves tend to be attenuated or replaced by beta activity when an individual is fully alert and actively concentrating. *Awake with eyes open* - When a person's eyes are open while awake, **alpha waves** are usually suppressed or "blocked" by visual input and mental processing. - This is known as **alpha blocking** or desynchronization, and the EEG shifts towards lower amplitude, higher frequency beta waves. *Deep sleep* - **Deep sleep** (Stage N3, or slow-wave sleep) is characterized by high-amplitude, low-frequency **delta waves** (0.5-4 Hz). - Alpha waves are not a prominent feature of deep sleep; instead, they are suppressed.
Question 9: The blood levels of hormones are elevated during exercise and sleep as shown. Which hormone would exhibit this diurnal pattern?
- A. Growth hormone (Correct Answer)
- B. Insulin
- C. Cortisol
- D. Thyroid hormones
Explanation: ***Growth hormone*** - **Growth hormone (GH)** secretion is known to increase significantly during both **strenuous exercise** and **sleep**, particularly during deep sleep stages. - The elevated levels during exercise promote **lipolysis** and **glucose production**, while during sleep, it facilitates **tissue repair** and **growth**. *Insulin* - **Insulin** levels typically **decrease during exercise** to promote the utilization of fat as fuel and increase during sleep in response to reduced metabolic demand and preparation for morning. - Its primary role is to regulate blood glucose, and its secretion is mainly stimulated by **high blood glucose** rather than exercise or sleep directly in this pattern. *Cortisol* - **Cortisol** secretion follows a **circadian rhythm**, peaking in the early morning and gradually decreasing throughout the day, reaching its lowest point at night. - While exercise can acutely increase cortisol, its **sleep-related pattern** is the opposite of what is shown, typically decreasing during early sleep. *Thyroid* - **Thyroid hormones (T3 and T4)** maintain a relatively **stable level** throughout the day and night, with minor diurnal fluctuations. - Their primary function is to regulate **metabolism** and they do not exhibit sharp, distinct peaks in response to exercise or sleep in the manner depicted.
Question 10: Which wave is seen in the given EEG recording?
- A. Alpha waves
- B. Beta waves
- C. Epsilon wave
- D. Delta waves (Correct Answer)
Explanation: ***Delta waves*** - The highlighted EEG activity shows **large amplitude, low-frequency waves** (typically 0.5-4 Hz), which are characteristic of delta waves. - Delta waves are normally associated with **deep sleep** (NREM stage 3) or **pathological conditions** in awake adults, indicating significant brain dysfunction. *Alpha waves* - Alpha waves have a frequency range of **8-13 Hz** and typically appear when an individual is in a relaxed, awake state with eyes closed. - The waves in the image are much slower and higher in amplitude than typical alpha waves. *Beta waves* - Beta waves are characterized by a higher frequency range of **14-30 Hz** and are associated with active thinking, alertness, and concentration. - The observed activity is significantly slower and higher in amplitude than beta waves. *Epsilon wave* - The term "epsilon wave" is not a standard classification for EEG brain waves in the context of normal or common pathological activity, unlike alpha, beta, theta, and delta waves. - In cardiology, "epsilon wave" refers to a specific finding on an ECG in **Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)**, not an EEG.
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