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ABOHNS Sleep Medicine study materials
ABOHNS Sleep Medicine study resources

ABOHNS Sleep Medicine practice questions

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Question 1Normal Sleep and Sleep-Wake Regulation

In a healthy adult, which sleep stage occupies the greatest proportion of total sleep time?

  1. Stage N3
  2. REM sleep
  3. Stage N1
  4. Stage N2 Correct answer.

Explanation

Stage N2 is the most abundant sleep stage in healthy adults, typically making up roughly 45-55% of total sleep time. N3 and REM each occupy smaller fractions, and N1 is brief.

Question 2Normal Sleep and Sleep-Wake Regulation

Which EEG rhythm characterizes quiet wakefulness with eyes closed over the occipital region?

  1. Beta rhythm
  2. Alpha rhythm Correct answer.
  3. Theta rhythm
  4. Delta rhythm

Explanation

Alpha activity (8-13 Hz) appears over posterior/occipital regions during relaxed wakefulness with eyes closed and attenuates with eye opening. Other rhythms dominate in different states or regions.

Question 3Normal Sleep and Sleep-Wake Regulation

A person's core body temperature minimum typically occurs at what point relative to habitual sleep?

  1. At the midpoint of the sleep episode
  2. Shortly after habitual wake time
  3. In the early morning, a few hours before habitual wake time Correct answer.
  4. In the late evening before sleep onset

Explanation

The circadian core temperature nadir normally occurs in the early morning hours, roughly 2-3 hours before habitual awakening. This nadir anchors the circadian phase and is used as a phase marker.

Question 4Normal Sleep and Sleep-Wake Regulation

Which neurotransmitter system is most strongly associated with promoting wakefulness through the ascending arousal system?

  1. Melatonin
  2. Adenosine
  3. Orexin/hypocretin Correct answer.
  4. GABA

Explanation

Orexin (hypocretin) neurons in the lateral hypothalamus stabilize wakefulness and arousal; loss of orexin neurons causes narcolepsy with cataplexy. The other substances generally promote sleep or sleep pressure.

Question 5Normal Sleep and Sleep-Wake Regulation

Approximately what proportion of a normal adult's night is spent in REM sleep?

  1. 5%
  2. 60-70%
  3. 20-25% Correct answer.
  4. 40-50%

Explanation

REM sleep typically constitutes about 20-25% of total sleep time in healthy adults. It is higher in infants and declines across the lifespan.

Question 6Normal Sleep and Sleep-Wake Regulation

During a normal night, REM sleep periods are typically distributed in which pattern?

  1. Absent until the final hour of sleep
  2. Concentrated in the first third of the night
  3. Concentrated in the latter part of the night Correct answer.
  4. Evenly distributed across the night

Explanation

REM periods lengthen across successive sleep cycles, so REM is concentrated in the second half of the night, while slow-wave sleep predominates early. This distribution matters clinically because late-night awakenings disproportionately reduce REM.

Question 7Normal Sleep and Sleep-Wake Regulation

A researcher wants to measure circadian phase using salivary melatonin in dim light. Which marker is most appropriate?

  1. Sleep onset latency
  2. Total sleep time
  3. Dim light melatonin onset (DLMO) Correct answer.
  4. Peak cortisol immediately after awakening

Explanation

DLMO is a validated phase marker reflecting the rise of melatonin in the evening under dim light, used to estimate circadian phase. Cortisol awakening response and sleep measures are influenced by many factors and are not direct phase markers.

Question 8Normal Sleep and Sleep-Wake Regulation

A 25-year-old reports difficulty falling asleep until 2-3 AM and difficulty waking for an 8 AM job, with improvement on free days. This pattern most suggests which circadian disorder?

  1. Irregular sleep-wake rhythm disorder
  2. Advanced sleep-wake phase disorder
  3. Delayed sleep-wake phase disorder Correct answer.
  4. Non-24-hour sleep-wake rhythm disorder

Explanation

Delayed sleep-wake phase disorder features a habitual sleep-wake timing that is delayed relative to social demands, with difficulty initiating sleep at the desired time and improvement when allowed to follow the delayed schedule. Advanced phase disorder shows the opposite (early sleep and wake).

Question 9Normal Sleep and Sleep-Wake Regulation

Which homeostatic factor is thought to accumulate during prolonged wakefulness and increase sleep pressure?

  1. Acetylcholine
  2. Orexin
  3. Histamine
  4. Adenosine Correct answer.

Explanation

Adenosine accumulates in the brain during wakefulness and rises with sleep deprivation, contributing to homeostatic sleep pressure; caffeine antagonizes adenosine receptors. The other transmitters are arousal-promoting rather than sleep-pressure signals.

Question 10Normal Sleep and Sleep-Wake Regulation

During polysomnography, which EEG feature marks the transition into stage N2 sleep?

  1. Sawtooth waves with rapid eye movements
  2. Alpha attenuation with slow rolling eye movements
  3. Sleep spindles and K-complexes Correct answer.
  4. Continuous high-amplitude delta waves

Explanation

Stage N2 is defined by the appearance of sleep spindles and/or K-complexes against a mixed-frequency background. Alpha attenuation with slow eye movements marks N1, and delta waves mark N3.

Question 11Normal Sleep and Sleep-Wake Regulation

In a standard hypnogram of a healthy young adult, which sequence best describes the first sleep cycle after sleep onset?

  1. N3 to N2 to REM to N1
  2. N2 to REM to N3 to N1
  3. N1 to N2 to N3 to REM Correct answer.
  4. REM to N1 to N2 to N3

Explanation

Sleep normally progresses from N1 into N2 and then into N3 before the first REM period, and the first cycle tends to have the most slow-wave sleep. Subsequent cycles have less N3 and longer REM.

Question 12Normal Sleep and Sleep-Wake Regulation

A blind individual without light perception reports a sleep schedule that drifts progressively later each day. This most likely reflects which condition?

  1. Insufficient sleep syndrome
  2. Non-24-hour sleep-wake rhythm disorder Correct answer.
  3. Shift work disorder
  4. Delayed sleep-wake phase disorder

Explanation

In the absence of light entrainment, the endogenous circadian period (often slightly longer than 24 hours) causes a progressive drift in sleep timing, producing non-24-hour sleep-wake rhythm disorder. Delayed phase disorder is a stable delay, not a daily drift.

Question 13Normal Sleep and Sleep-Wake Regulation

Which statement best describes the interaction of homeostatic and circadian processes in the two-process model of sleep regulation?

  1. Circadian alerting signal and sleep pressure interact to shape sleep timing and depth Correct answer.
  2. Sleep propensity is determined solely by time awake
  3. Circadian rhythm is a direct product of accumulated adenosine
  4. REM sleep is regulated independently of both processes

Explanation

The two-process model posits that homeostatic sleep pressure (Process S) and circadian timing (Process C) interact to determine sleep propensity and timing. The circadian alerting signal opposes rising sleep pressure to maintain wakefulness across the day.

Question 14Normal Sleep and Sleep-Wake Regulation

Which finding on polysomnography is most characteristic of REM sleep?

  1. Vertex sharp waves with alpha activity
  2. High chin EMG tone with slow eye movements
  3. Low chin EMG tone with rapid eye movements Correct answer.
  4. Sleep spindles with K-complexes

Explanation

REM sleep is defined by low-amplitude mixed-frequency EEG, rapid eye movements, and atonia reflected in low chin EMG tone. Spindles and K-complexes mark N2, and slow eye movements accompany N1.

Question 15Normal Sleep and Sleep-Wake Regulation

A patient's dim light melatonin onset occurs several hours later than normal, consistent with a delayed circadian phase. Which timing of bright light exposure would most appropriately advance the phase?

  1. Bright light at the circadian temperature minimum
  2. Bright light in the early morning after habitual wake Correct answer.
  3. Bright light in the late evening before bed
  4. Bright light in the middle of the night

Explanation

Light exposure in the morning (after the temperature minimum) produces a phase advance, whereas evening light before the minimum delays the rhythm. Timing relative to the circadian phase, not the clock alone, determines the direction of shift.

Question 16Normal Sleep and Sleep-Wake Regulation

Which EEG pattern is expected during stage N3 sleep?

  1. Alpha rhythm with eye closure
  2. Beta activity with muscle artifact
  3. Low-voltage mixed-frequency activity with sawtooth waves
  4. Slow waves of 0.5-2 Hz occupying a substantial portion of the epoch Correct answer.

Explanation

Stage N3 is defined by slow-wave activity in the delta range (0.5-2 Hz) of sufficient amplitude occupying a substantial fraction of the epoch. This stage predominates in early sleep cycles and in children.

Question 17Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which recording channel is used to stage sleep by identifying K-complexes and sleep spindles?

  1. Electroencephalogram (EEG) Correct answer.
  2. Electrooculogram (EOG)
  3. Electrocardiogram (ECG)
  4. Electromyogram (EMG)

Explanation

Sleep staging depends on cortical EEG features such as K-complexes, sleep spindles, and slow waves. EOG and EMG support staging by documenting eye movements and muscle tone but do not define these waveforms.

Question 18Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

During polysomnography, chin EMG tone is typically lowest in which sleep stage?

  1. Stage N3
  2. Stage N2
  3. Wakefulness
  4. REM sleep Correct answer.

Explanation

REM sleep is characterized by skeletal muscle atonia, reflected in the lowest chin EMG amplitude of the night. NREM stages and wakefulness retain higher tonic muscle activity.

Question 19Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which parameter defines a hypopnea under the AASM recommended scoring rule?

  1. A 50% or greater drop in airflow lasting at least 30 seconds
  2. A 30% or greater drop in airflow with 3% desaturation or an arousal Correct answer.
  3. Any visible airflow reduction accompanied by snoring
  4. A 10% airflow drop with no desaturation or arousal

Explanation

The recommended AASM rule requires a 30% or greater reduction in nasal pressure airflow lasting at least 10 seconds, with a 3% oxygen desaturation or an arousal. The alternative rule uses a 4% desaturation threshold.

Question 20Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

A respiratory event is scored as an apnea when airflow reduction meets which criterion?

  1. A 50% reduction for at least 10 seconds
  2. A 30% reduction with arousal
  3. Any reduction lasting 5 seconds
  4. A 90% or greater reduction for at least 10 seconds Correct answer.

Explanation

An apnea requires a 90% or greater drop in airflow lasting at least 10 seconds (or a complete cessation). Lesser reductions that meet desaturation or arousal criteria are scored as hypopneas.

Question 21Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

The apnea-hypopnea index (AHI) is calculated by dividing the total number of apneas and hypopneas by which value?

  1. Number of arousals
  2. Total recording time in hours
  3. Total sleep time in hours Correct answer.
  4. Number of sleep cycles

Explanation

AHI uses total sleep time as the denominator, expressed per hour of sleep. Using total recording time instead yields the respiratory event index used in home testing where sleep time is not measured.

Question 22Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which oxygen desaturation threshold is used in the AASM recommended hypopnea scoring rule?

  1. 3% Correct answer.
  2. 4%
  3. 2%
  4. 5%

Explanation

The recommended rule uses a 3% desaturation or an arousal to accompany a 30% airflow reduction. The acceptable alternative rule uses a 4% desaturation without requiring arousal.

Question 23Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which finding on a polysomnogram is required to score an arousal during REM sleep?

  1. An increase in chin EMG lasting at least 1 second together with an EEG frequency shift Correct answer.
  2. A single K-complex without any frequency change
  3. A drop in heart rate of 10 beats per minute
  4. A slow eye movement lasting 2 seconds

Explanation

In REM, an arousal requires an abrupt EEG frequency shift plus a concurrent increase in chin EMG lasting at least 1 second. In NREM, the EMG increase is not required unless the arousal occurs during REM.

Question 24Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which EEG pattern characterizes stage N1 sleep?

  1. Continuous delta waves occupying more than 20% of the epoch
  2. Sleep spindles occurring every 2 seconds
  3. Alpha rhythm occupying more than 50% of the epoch
  4. Low-amplitude mixed-frequency activity with vertex sharp waves Correct answer.

Explanation

Stage N1 is defined by low-amplitude mixed-frequency EEG, often with vertex sharp waves and slow eye movements. Alpha attenuation to less than 50% of the epoch marks the transition from wake to N1.

Question 25Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Stage N3 sleep is scored when slow waves occupy at least what percentage of an epoch?

  1. 10%
  2. 20% Correct answer.
  3. 80%
  4. 50%

Explanation

Stage N3 requires slow waves of 0.5 to 2 Hz with peak-to-peak amplitude greater than 75 microvolts occupying 20% or more of the epoch. This threshold was lowered from the older 20% criterion for stage 3/4 distinction.

Question 26Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which feature is required to begin scoring stage N2 sleep?

  1. A chin EMG increase of 50%
  2. An alpha rhythm in more than 50% of the epoch
  3. A slow eye movement
  4. A K-complex or sleep spindle in the absence of an arousal Correct answer.

Explanation

Stage N2 begins with the appearance of a K-complex unassociated with arousal or a sleep spindle. Once N2 criteria are met, the stage continues until a transition to another stage occurs.

Question 27Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Rapid eye movements in REM sleep are best identified on which channel?

  1. ECG with R-R variability
  2. Central EEG with alpha rhythm
  3. Chin EMG with tonic activity
  4. Left and right EOG with out-of-phase deflections Correct answer.

Explanation

Rapid eye movements produce conjugate, out-of-phase deflections on left and right EOG channels. This out-of-phase pattern distinguishes eye movements from EEG artifact.

Question 28Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which criterion must be met to score REM sleep?

  1. High-amplitude delta waves and high chin EMG
  2. Low-amplitude mixed-frequency EEG, low chin EMG, and rapid eye movements Correct answer.
  3. Alpha rhythm and slow eye movements
  4. Sleep spindles and K-complexes with high chin EMG

Explanation

REM requires low-amplitude mixed-frequency EEG, the lowest chin EMG of the study, and rapid eye movements. Transitions into REM can occur without rapid eye movements if EEG and EMG criteria are met.

Question 29Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

A patient undergoes home sleep apnea testing with a type 3 device. Which parameter is typically NOT measured?

  1. Nasal airflow
  2. Oxygen saturation
  3. Respiratory effort
  4. Total sleep time Correct answer.

Explanation

Type 3 portable monitors measure airflow, effort, oximetry, and often position or heart rate but do not record EEG, so sleep time is not directly measured. This is why home studies report a respiratory event index rather than AHI.

Question 30Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which patient is the most appropriate candidate for home sleep apnea testing?

  1. A patient with chronic opioid use and nocturnal hypoventilation
  2. A patient with a high pretest probability of moderate to severe OSA and no significant comorbidity Correct answer.
  3. A patient with suspected narcolepsy
  4. A patient with severe heart failure and suspected central sleep apnea

Explanation

Home sleep apnea testing is appropriate for adults with a high pretest probability of moderate to severe OSA without significant cardiopulmonary or neurologic comorbidity. It is not appropriate when central apnea, hypoventilation, or another sleep disorder is suspected.

Question 31Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

A home sleep apnea test returns a negative result in a patient with a high clinical suspicion of OSA. What is the most appropriate next step?

  1. Reassure the patient that OSA is excluded
  2. Proceed to attended polysomnography Correct answer.
  3. Repeat the same home test immediately
  4. Start empiric CPAP without further testing

Explanation

A negative home study does not exclude OSA when pretest probability is high, and attended polysomnography is recommended for confirmation. Home devices underestimate events because they do not measure sleep time or arousals.

Question 32Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which measure does actigraphy primarily estimate?

  1. Respiratory effort
  2. Sleep-disordered breathing severity
  3. Arterial oxygen saturation
  4. Sleep-wake patterns over multiple days Correct answer.

Explanation

Actigraphy uses wrist movement to estimate sleep-wake patterns over extended periods, typically one to two weeks. It is useful for circadian rhythm disorders and insomnia but does not measure respiration or oxygenation.

Question 33Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Actigraphy is most useful in the evaluation of which condition?

  1. Nocturnal hypoventilation
  2. Circadian rhythm sleep-wake disorders Correct answer.
  3. Obstructive sleep apnea
  4. Central sleep apnea

Explanation

Actigraphy documents rest-activity patterns over days to weeks, making it well suited to circadian rhythm disorders such as delayed sleep phase syndrome. It cannot diagnose respiratory disorders.

Question 34Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which electrode placement is standard for the occipital EEG channels used in sleep staging?

  1. F3-M2 and F4-M1
  2. O1-M2 and O2-M1 Correct answer.
  3. E1-M2 and E2-M1
  4. C3-M2 and C4-M1

Explanation

Occipital derivations O1-M2 and O2-M1 are used to detect alpha rhythm during wakefulness. Central channels (C3/C4) are used for spindles and K-complexes, and frontal channels for slow waves.

Question 35Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

What is the standard sampling rate and filter setting commonly recommended for EEG during polysomnography?

  1. 10 Hz sampling with a 0.1 Hz filter
  2. 1000 Hz sampling with no filter
  3. 200 Hz sampling with a 0.3 Hz low-frequency filter Correct answer.
  4. 50 Hz sampling with a 35 Hz filter

Explanation

AASM guidelines recommend EEG sampled at a minimum of 200 Hz with a low-frequency filter of 0.3 Hz and a high-frequency filter of 35 Hz. These settings preserve slow waves and spindles while limiting artifact.

Question 36Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

A 30-second epoch shows 12 seconds of slow waves meeting amplitude criteria, with the remainder showing low-amplitude mixed-frequency activity. How should the epoch be scored?

  1. Stage N1
  2. Stage N2
  3. Stage N3 Correct answer.
  4. REM

Explanation

Slow waves occupying 20% or more of a 30-second epoch (6 seconds) meet criteria for N3. Twelve seconds exceeds this threshold, so the epoch is scored as N3.

Question 37Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

A patient's polysomnogram shows an AHI of 18 events per hour with 12% of total sleep time below 90% oxygen saturation. How is the OSA severity classified?

  1. Severe
  2. Normal
  3. Mild
  4. Moderate Correct answer.

Explanation

An AHI between 15 and 30 events per hour defines moderate OSA. Mild OSA is 5 to 15, and severe OSA is greater than 30 events per hour.

Question 38Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which finding on a polysomnogram suggests a central rather than obstructive apnea?

  1. Progressive increase in effort before the event
  2. Snoring preceding the event
  3. Absent respiratory effort with absent airflow Correct answer.
  4. Continued respiratory effort with absent airflow

Explanation

Central apnea is characterized by absent airflow without respiratory effort, reflecting a lack of central respiratory drive. Obstructive apnea shows continued or increased effort against an occluded airway.

Question 39Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which parameter distinguishes a type 4 portable monitor from a type 3 device?

  1. Type 4 includes EEG and EOG
  2. Type 4 measures only one or two channels such as oximetry Correct answer.
  3. Type 4 requires attended technologist monitoring
  4. Type 4 measures respiratory effort and airflow

Explanation

Type 4 devices are limited-channel monitors, often measuring only oximetry or airflow, whereas type 3 devices include multiple channels. Neither type records EEG or requires attended monitoring.

Question 40Sleep Evaluation and Diagnostic Testing (Polysomnography, Home Sleep Apnea Testing, Actigraphy)

Which artifact on a polysomnogram most commonly mimics a slow wave on EEG?

  1. 60 Hz electrical interference
  2. Sweat artifact Correct answer.
  3. EKG artifact
  4. Muscle artifact

Explanation

Sweat artifact produces slow, high-amplitude wandering baseline deflections that can resemble delta waves. It is distinguished by its very low frequency and lack of correspondence to other sleep features.

Question 41Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

A 52-year-old man with a BMI of 34 kg/m² and witnessed apneas undergoes a diagnostic polysomnogram. Which apnea-hypopnea index threshold establishes the diagnosis of obstructive sleep apnea in an adult with compatible symptoms?

  1. At least 15 events per hour
  2. At least 5 events per hour Correct answer.
  3. At least 30 events per hour
  4. At least 10 events per hour

Explanation

OSA is diagnosed when the AHI is ≥5/hour with attributable symptoms or comorbidities, or when the AHI is ≥15/hour regardless of symptoms. The higher thresholds reflect severity grading rather than the diagnostic cutoff.

Question 42Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

Which finding on history most strongly suggests that a patient's excessive daytime sleepiness is due to obstructive sleep apnea rather than insufficient sleep alone?

  1. Sleepiness that improves on weekends
  2. A stable body weight over the past year
  3. Sleep-onset latency under 10 minutes
  4. Witnessed apneas reported by a bed partner Correct answer.

Explanation

Witnessed apneas are a specific nocturnal symptom of OSA, indicating recurrent upper airway obstruction during sleep. Weekend improvement and short sleep latency are nonspecific and also occur with chronic sleep restriction.

Question 43Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

Which nocturnal symptom pattern is most characteristic of obstructive sleep apnea in an adult?

  1. Restless legs relieved by movement
  2. Sleep attacks with cataplexy
  3. Loud habitual snoring with witnessed breathing pauses Correct answer.
  4. Early morning awakening with depressed mood

Explanation

Loud snoring interrupted by witnessed apneas or gasping arousals is the hallmark nocturnal presentation of OSA. The other options describe narcolepsy, mood disorders, and restless legs syndrome respectively.

Question 44Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

A 45-year-old woman has an AHI of 22 events per hour on polysomnography and no reported daytime symptoms. How is her OSA severity classified?

  1. Moderate OSA Correct answer.
  2. Mild OSA
  3. Severe OSA
  4. Not classifiable without symptoms

Explanation

Severity is graded by AHI: 5 to <15 is mild, 15 to <30 is moderate, and ≥30 is severe. An AHI of 22 falls in the moderate range, and severity grading does not require symptoms.

Question 45Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

Which anthropometric feature is most strongly associated with obstructive sleep apnea in adults?

  1. Increased lower limb length
  2. Decreased waist-to-hip ratio
  3. Increased neck circumference Correct answer.
  4. Increased standing height

Explanation

A large neck circumference reflects peripharyngeal fat deposition that narrows the upper airway and is a recognized OSA risk factor. The other measurements are not established predictors of pharyngeal collapsibility.

Question 46Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

Which condition is most commonly associated with central sleep apnea rather than obstructive sleep apnea?

  1. Tonsillar hypertrophy
  2. Congestive heart failure Correct answer.
  3. Nasal septal deviation
  4. Retrognathia

Explanation

Central sleep apnea, particularly Cheyne-Stokes respiration, is strongly linked to congestive heart failure through prolonged circulation time and altered chemosensitivity. The other options are anatomic causes of upper airway obstruction.

Question 47Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

What does the respiratory disturbance index (RDI) include that the apnea-hypopnea index (AHI) does not?

  1. Hypopneas scored with a 4% desaturation
  2. Respiratory effort-related arousals Correct answer.
  3. Obstructive apneas
  4. Central apneas

Explanation

The RDI adds respiratory effort-related arousals to the apneas and hypopneas counted in the AHI. Central and obstructive apneas and hypopneas are components of the AHI itself.

Question 48Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

Which daytime consequence is most directly attributable to obstructive sleep apnea in adults?

  1. Nocturnal enuresis in adulthood
  2. Excessive daytime sleepiness with impaired vigilance Correct answer.
  3. Progressive cognitive decline over decades
  4. Chronic productive cough

Explanation

Recurrent arousals and sleep fragmentation in OSA produce excessive daytime sleepiness and reduced vigilance, which raise accident risk. The other options are not the principal daytime consequence of OSA.

Question 49Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

A 60-year-old man with resistant hypertension and an AHI of 18/hour has failed a trial of mandibular advancement and prefers a device-based therapy. Which treatment is the first-line therapy for moderate-to-severe OSA in adults?

  1. Positive airway pressure therapy Correct answer.
  2. Positional therapy alone
  3. Uvulopalatopharyngoplasty
  4. Oral theophylline

Explanation

Positive airway pressure is first-line for moderate-to-severe OSA because it reliably eliminates obstructive events and improves symptoms. Surgery, pharmacotherapy, and positional therapy are reserved for selected or refractory cases.

Question 50Sleep-Disordered Breathing in Adults: Obstructive Sleep Apnea

A patient on CPAP at a fixed pressure of 12 cm H2O reports persistent sleepiness and the device download shows a residual AHI of 14/hour with frequent large leaks. What is the most appropriate next step?

  1. Add a hypnotic to improve adherence
  2. Discontinue CPAP and start an oral appliance
  3. Address mask fit and leak before reassessing pressure Correct answer.
  4. Increase the fixed pressure to 16 cm H2O

Explanation

Persistent events in the setting of large leaks usually reflect inadequate pressure delivery from leak rather than insufficient pressure. Correcting the interface and leak is the logical first step before retitration.