Basic Concepts of Polysomnography
1. What is the primary diagnostic tool used to evaluate
sleep disorders?
A. Pulse oximetry
B. Polysomnography (PSG)
C. Arterial blood gas (ABG) analysis
D. Capnography
Answer: B.
Explanation: Polysomnography (PSG) is the gold standard for diagnosing sleep disorders by monitoring multiple physiological parameters.
2. Which of the following is NOT a standard parameter
measured during polysomnography?
A. Electroencephalogram (EEG)
B. Electromyogram (EMG)
C. Forced expiratory volume (FEV1)
D. Electrooculogram (EOG)
Answer: C.
Explanation: FEV1 is a pulmonary function test (PFT) parameter, not typically measured during PSG.
3. Which sleep disorder is characterized by repeated
episodes of upper airway obstruction during sleep?
A. Narcolepsy
B. Obstructive sleep apnea (OSA)
C. Central sleep apnea (CSA)
D. Restless leg syndrome
Answer: B.
Explanation: OSA occurs due to upper airway collapse, leading to intermittent breathing pauses during sleep.
4. Which sleep stage is characterized by rapid eye
movement (REM), vivid dreams, and muscle atonia?
A. Stage 1
B. Stage 2
C. Stage 3
D. REM sleep
Answer: D.
Explanation: REM sleep is associated with dreaming, rapid eye movements, and muscle paralysis (except for breathing muscles).
5. Which brain activity pattern is most dominant during
deep (slow-wave) sleep?
A. Alpha waves
B. Beta waves
C. Delta waves
D. Theta waves
Answer: C.
Explanation: Delta waves are prominent during stage 3 sleep, which is essential for physical restoration.
Sleep Apnea and Respiratory Events
6. What is the apnea-hypopnea index (AHI) used for?
A. To assess lung volumes
B. To measure oxygen saturation levels
C. To determine sleep disorder severity
D. To monitor CO2 retention
Answer: C.
Explanation: AHI quantifies the severity of sleep apnea by measuring the number of apnea and hypopnea events per hour.
7. What AHI value is considered diagnostic of moderate
obstructive sleep apnea (OSA)?
A. 5-14 events/hour
B. 15-29 events/hour
C. 30-49 events/hour
D. >50 events/hour
Answer: B.
Explanation: Moderate OSA is diagnosed when AHI is between 15 and 29 events per hour.
8. Which event is defined as a complete cessation of
airflow for at least 10 seconds?
A. Hypopnea
B. Apnea
C. RERA (Respiratory Effort-Related Arousal)
D. Snoring
Answer: B.
Explanation: Apnea is a complete airflow cessation lasting at least 10 seconds.
9. Which of the following is a characteristic feature of
central sleep apnea (CSA)?
A. Airflow cessation with persistent respiratory effort
B. Absence of both airflow and respiratory effort
C. Airflow cessation due to airway obstruction
D. Increased snoring
Answer: B.
Explanation: CSA is caused by impaired brain signaling, leading to no airflow and no respiratory effort.
10. What is the main physiological consequence of
untreated obstructive sleep apnea (OSA)?
A. Increased tidal volume
B. Chronic hypoxemia and cardiovascular disease
C. Decreased respiratory rate
D. Hyperventilation
Answer: B.
Explanation: OSA leads to chronic oxygen desaturation, hypertension, and increased cardiovascular risk.
Polysomnography Interpretation and Therapy
11. What device is commonly used to treat obstructive
sleep apnea (OSA)?
A. Nasal cannula
B. Incentive spirometer
C. Nebulizer
D. CPAP (Continuous Positive Airway Pressure)
Answer: D.
Explanation: CPAP maintains airway patency and prevents airway collapse in OSA patients.
12. Which component of a polysomnogram detects airflow?
A. Thermistor or nasal pressure transducer
B. Electroencephalogram (EEG)
C. Pulse oximeter
D. Electrocardiogram (ECG)
Answer: A.
Explanation: Nasal thermistors and pressure transducers measure airflow fluctuations during sleep.
13. Which of the following is NOT a common symptom of
sleep apnea?
A. Loud snoring
B. Daytime sleepiness
C. Morning headaches
D. Hyperactivity
Answer: D.
Explanation: Sleep apnea is associated with fatigue, not hyperactivity.
14. Which oxygen desaturation level is commonly used to
define a hypopnea event?
A. ≥2% decrease
B. ≥3% decrease
C. ≥4% decrease
D. ≥5% decrease
Answer: C.
Explanation: A ≥4% oxygen desaturation from baseline is used to classify a hypopnea event.
15. What term describes the transition from wakefulness
to sleep?
A. Sleep inertia
B. Sleep onset
C. REM rebound
D. Sleep fragmentation
Answer: B.
Explanation: Sleep onset marks the transition from wakefulness to sleep, typically into stage 1 sleep.
16. Which of the following conditions is associated with
REM sleep behavior disorder?
A. Uncontrolled limb movements during REM sleep
B. Excessive daytime sleepiness
C. Sleepwalking
D. Narcolepsy
Answer: A.
Explanation: REM Sleep Behavior Disorder (RBD) is a parasomnia where individuals act out vivid dreams due to a lack of muscle atonia (paralysis) during REM sleep. Normally, muscles are temporarily paralyzed during REM sleep, preventing physical movement. However, in RBD, this paralysis is lost, leading to uncontrolled limb movements, punching, kicking, or even vocalizing during dreams.
17. A patient with obesity, excessive daytime sleepiness,
and chronic hypoventilation may have:
A. Narcolepsy
B. Obesity hypoventilation syndrome (OHS)
C. Central sleep apnea
D. Restless leg syndrome
Answer: B.
Explanation: Obesity Hypoventilation Syndrome (OHS) is a disorder seen in obese individuals where there is chronic hypoventilation (reduced breathing efficiency) leading to elevated carbon dioxide (CO₂) levels and low oxygen levels (hypoxemia), especially during sleep. It is strongly associated with excessive daytime sleepiness, loud snoring, and obstructive sleep apnea (OSA).
Advanced Concepts in Sleep Studies
18. Which sleep disorder is characterized by excessive
daytime sleepiness and sudden muscle weakness triggered by emotions?
A. Obstructive sleep apnea (OSA)
B. Insomnia
C. Central sleep apnea (CSA)
D. Narcolepsy with cataplexy
Answer: D.
Explanation: Narcolepsy with cataplexy involves sudden loss of muscle tone due to emotional triggers, often with REM sleep abnormalities.
19. What is the gold standard method for diagnosing
narcolepsy?
A. Overnight polysomnography (PSG)
B. Multiple Sleep Latency Test (MSLT)
C. Actigraphy
D. Home sleep apnea test (HSAT)
Answer: B.
Explanation: MSLT measures sleep latency (time to fall asleep) and identifies REM sleep-onset periods, key indicators of narcolepsy.
20. Which sleep-related breathing disorder is most
commonly associated with obesity?
A. Obesity hypoventilation syndrome (OHS)
B. Narcolepsy
C. Restless legs syndrome (RLS)
D. Periodic limb movement disorder (PLMD)
Answer: A.
Explanation: OHS, also called Pickwickian syndrome, is associated with chronic hypoventilation and obesity, often coexisting with OSA.
21. What condition is characterized by uncontrollable leg
movements at rest, often worsening at night?
A. Central sleep apnea
B. REM sleep behavior disorder
C. Restless legs syndrome (RLS)
D. Sleepwalking
Answer: C.
Explanation: RLS causes an urge to move the legs and is relieved by movement, often linked to iron deficiency.
22. Which test is used to assess circadian rhythm
disorders?
A. Multiple Sleep Latency Test (MSLT)
B. Home sleep apnea test (HSAT)
C. Actigraphy
D. Epworth Sleepiness Scale (ESS)
Answer: C.
Explanation: Actigraphy records sleep-wake patterns using a wrist-worn device, useful for evaluating circadian rhythm disorders.
23. Which of the following is a key finding in REM sleep
behavior disorder (RBD)?
A. Excessive daytime sleepiness
B. Sleep paralysis
C. Lack of muscle atonia in REM sleep
D. Frequent awakenings during Stage 3 sleep
Answer: C.
Explanation: RBD is characterized by abnormal muscle activity during REM sleep, leading to acting out dreams.
24. Which type of apnea occurs due to a lack of
respiratory effort from the brainstem?
A. Obstructive sleep apnea
B. Central sleep apnea
C. Complex sleep apnea
D. Cheyne-Stokes respiration
Answer: B.
Explanation: Central sleep apnea (CSA) is caused by impaired brain signaling, leading to pauses in breathing without airway obstruction.
25. What is the most common first-line treatment for
central sleep apnea?
A. CPAP therapy
B. Tracheostomy
C. Oxygen therapy
D. Bilevel Positive Airway Pressure (BiPAP) therapy
Answer: D.
Explanation: BiPAP therapy provides higher inspiratory pressure to support breathing, making it the preferred treatment for CSA.
26. What is the role of the Epworth Sleepiness Scale
(ESS) in sleep studies?
A. To measure oxygen desaturation
B. To quantify excessive daytime sleepiness
C. To diagnose sleep apnea severity
D. To assess leg movements during sleep
Answer: B.
Explanation: The ESS is a subjective questionnaire that assesses daytime sleepiness, commonly used in sleep disorder screening.
27. What is the term for brief, partial awakenings caused
by increased respiratory effort during sleep?
A. Apnea
B. Hypopnea
C. Respiratory Effort-Related Arousals (RERA)
D. Cataplexy
Answer: C.
Explanation: RERA events cause sleep fragmentation without meeting the criteria for apnea or hypopnea.
28. Which imaging modality is most useful for diagnosing
upper airway structural abnormalities in sleep apnea?
A. Chest X-ray
B. MRI
C. CT scan
D. Lateral neck X-ray
Answer: D.
Explanation: Lateral neck X-rays help assess upper airway narrowing and enlarged soft tissues that contribute to OSA.
A. Pulse oximetry
B. Polysomnography (PSG)
C. Arterial blood gas (ABG) analysis
D. Capnography
Answer: B.
Explanation: Polysomnography (PSG) is the gold standard for diagnosing sleep disorders by monitoring multiple physiological parameters.
A. Electroencephalogram (EEG)
B. Electromyogram (EMG)
C. Forced expiratory volume (FEV1)
D. Electrooculogram (EOG)
Answer: C.
Explanation: FEV1 is a pulmonary function test (PFT) parameter, not typically measured during PSG.
A. Narcolepsy
B. Obstructive sleep apnea (OSA)
C. Central sleep apnea (CSA)
D. Restless leg syndrome
Answer: B.
Explanation: OSA occurs due to upper airway collapse, leading to intermittent breathing pauses during sleep.
A. Stage 1
B. Stage 2
C. Stage 3
D. REM sleep
Answer: D.
Explanation: REM sleep is associated with dreaming, rapid eye movements, and muscle paralysis (except for breathing muscles).
A. Alpha waves
B. Beta waves
C. Delta waves
D. Theta waves
Answer: C.
Explanation: Delta waves are prominent during stage 3 sleep, which is essential for physical restoration.
A. To assess lung volumes
B. To measure oxygen saturation levels
C. To determine sleep disorder severity
D. To monitor CO2 retention
Answer: C.
Explanation: AHI quantifies the severity of sleep apnea by measuring the number of apnea and hypopnea events per hour.
A. 5-14 events/hour
B. 15-29 events/hour
C. 30-49 events/hour
D. >50 events/hour
Answer: B.
Explanation: Moderate OSA is diagnosed when AHI is between 15 and 29 events per hour.
A. Hypopnea
B. Apnea
C. RERA (Respiratory Effort-Related Arousal)
D. Snoring
Answer: B.
Explanation: Apnea is a complete airflow cessation lasting at least 10 seconds.
A. Airflow cessation with persistent respiratory effort
B. Absence of both airflow and respiratory effort
C. Airflow cessation due to airway obstruction
D. Increased snoring
Answer: B.
Explanation: CSA is caused by impaired brain signaling, leading to no airflow and no respiratory effort.
A. Increased tidal volume
B. Chronic hypoxemia and cardiovascular disease
C. Decreased respiratory rate
D. Hyperventilation
Answer: B.
Explanation: OSA leads to chronic oxygen desaturation, hypertension, and increased cardiovascular risk.
A. Nasal cannula
B. Incentive spirometer
C. Nebulizer
D. CPAP (Continuous Positive Airway Pressure)
Answer: D.
Explanation: CPAP maintains airway patency and prevents airway collapse in OSA patients.
A. Thermistor or nasal pressure transducer
B. Electroencephalogram (EEG)
C. Pulse oximeter
D. Electrocardiogram (ECG)
Answer: A.
Explanation: Nasal thermistors and pressure transducers measure airflow fluctuations during sleep.
A. Loud snoring
B. Daytime sleepiness
C. Morning headaches
D. Hyperactivity
Answer: D.
Explanation: Sleep apnea is associated with fatigue, not hyperactivity.
A. ≥2% decrease
B. ≥3% decrease
C. ≥4% decrease
D. ≥5% decrease
Answer: C.
Explanation: A ≥4% oxygen desaturation from baseline is used to classify a hypopnea event.
A. Sleep inertia
B. Sleep onset
C. REM rebound
D. Sleep fragmentation
Answer: B.
Explanation: Sleep onset marks the transition from wakefulness to sleep, typically into stage 1 sleep.
A. Uncontrolled limb movements during REM sleep
B. Excessive daytime sleepiness
C. Sleepwalking
D. Narcolepsy
Answer: A.
Explanation: REM Sleep Behavior Disorder (RBD) is a parasomnia where individuals act out vivid dreams due to a lack of muscle atonia (paralysis) during REM sleep. Normally, muscles are temporarily paralyzed during REM sleep, preventing physical movement. However, in RBD, this paralysis is lost, leading to uncontrolled limb movements, punching, kicking, or even vocalizing during dreams.
A. Narcolepsy
B. Obesity hypoventilation syndrome (OHS)
C. Central sleep apnea
D. Restless leg syndrome
Answer: B.
Explanation: Obesity Hypoventilation Syndrome (OHS) is a disorder seen in obese individuals where there is chronic hypoventilation (reduced breathing efficiency) leading to elevated carbon dioxide (CO₂) levels and low oxygen levels (hypoxemia), especially during sleep. It is strongly associated with excessive daytime sleepiness, loud snoring, and obstructive sleep apnea (OSA).
A. Obstructive sleep apnea (OSA)
B. Insomnia
C. Central sleep apnea (CSA)
D. Narcolepsy with cataplexy
Answer: D.
Explanation: Narcolepsy with cataplexy involves sudden loss of muscle tone due to emotional triggers, often with REM sleep abnormalities.
A. Overnight polysomnography (PSG)
B. Multiple Sleep Latency Test (MSLT)
C. Actigraphy
D. Home sleep apnea test (HSAT)
Answer: B.
Explanation: MSLT measures sleep latency (time to fall asleep) and identifies REM sleep-onset periods, key indicators of narcolepsy.
A. Obesity hypoventilation syndrome (OHS)
B. Narcolepsy
C. Restless legs syndrome (RLS)
D. Periodic limb movement disorder (PLMD)
Answer: A.
Explanation: OHS, also called Pickwickian syndrome, is associated with chronic hypoventilation and obesity, often coexisting with OSA.
A. Central sleep apnea
B. REM sleep behavior disorder
C. Restless legs syndrome (RLS)
D. Sleepwalking
Answer: C.
Explanation: RLS causes an urge to move the legs and is relieved by movement, often linked to iron deficiency.
A. Multiple Sleep Latency Test (MSLT)
B. Home sleep apnea test (HSAT)
C. Actigraphy
D. Epworth Sleepiness Scale (ESS)
Answer: C.
Explanation: Actigraphy records sleep-wake patterns using a wrist-worn device, useful for evaluating circadian rhythm disorders.
A. Excessive daytime sleepiness
B. Sleep paralysis
C. Lack of muscle atonia in REM sleep
D. Frequent awakenings during Stage 3 sleep
Answer: C.
Explanation: RBD is characterized by abnormal muscle activity during REM sleep, leading to acting out dreams.
A. Obstructive sleep apnea
B. Central sleep apnea
C. Complex sleep apnea
D. Cheyne-Stokes respiration
Answer: B.
Explanation: Central sleep apnea (CSA) is caused by impaired brain signaling, leading to pauses in breathing without airway obstruction.
A. CPAP therapy
B. Tracheostomy
C. Oxygen therapy
D. Bilevel Positive Airway Pressure (BiPAP) therapy
Answer: D.
Explanation: BiPAP therapy provides higher inspiratory pressure to support breathing, making it the preferred treatment for CSA.
A. To measure oxygen desaturation
B. To quantify excessive daytime sleepiness
C. To diagnose sleep apnea severity
D. To assess leg movements during sleep
Answer: B.
Explanation: The ESS is a subjective questionnaire that assesses daytime sleepiness, commonly used in sleep disorder screening.
A. Apnea
B. Hypopnea
C. Respiratory Effort-Related Arousals (RERA)
D. Cataplexy
Answer: C.
Explanation: RERA events cause sleep fragmentation without meeting the criteria for apnea or hypopnea.
A. Chest X-ray
B. MRI
C. CT scan
D. Lateral neck X-ray
Answer: D.
Explanation: Lateral neck X-rays help assess upper airway narrowing and enlarged soft tissues that contribute to OSA.
29. What is the most common cause of non-respiratory-related insomnia?
A. Depression and anxiety
B. Obstructive sleep apnea
C. Periodic limb movement disorder
D. Narcolepsy
Answer: A.
Explanation: Psychological conditions, such as anxiety and depression, are major causes of chronic insomnia.
A. It is a continuous, rapid breathing pattern.
B. It involves gradual rises and falls in breathing effort.
C. It is caused by airway collapse.
D. It only occurs in REM sleep.
Answer: B.
Explanation: Cheyne-Stokes respiration is a cyclic breathing pattern with alternating deep and shallow breaths, often seen in heart failure patients.