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ABPN Sleep Medicine study materials
ABPN Sleep Medicine study resources

ABPN Sleep Medicine practice questions

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Question 1Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which EEG frequency band characterizes the majority of stage N2 sleep in a healthy adult?

  1. Alpha activity (8-13 Hz)
  2. Beta activity (13-30 Hz)
  3. Theta activity (4-7 Hz) Correct answer.
  4. Delta activity (0.5-2 Hz)

Explanation

Stage N2 is dominated by theta-range background frequencies punctuated by sleep spindles and K-complexes. Delta activity defines N3, alpha defines relaxed wakefulness with eyes closed, and beta reflects active wakefulness.

Question 2Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Sleep spindles are generated primarily through interactions between which structures?

  1. Thalamic reticular nucleus and thalamocortical relay neurons Correct answer.
  2. Suprachiasmatic nucleus and pineal gland
  3. Basal forebrain cholinergic neurons and cortex
  4. Locus coeruleus and dorsal raphe

Explanation

Spindles arise from rhythmic inhibition of thalamocortical relay cells by GABAergic neurons of the thalamic reticular nucleus, producing 11-16 Hz bursts. The other pairings describe circadian or arousal systems rather than spindle generators.

Question 3Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

K-complexes are best described as which of the following?

  1. Sustained rhythmic 8-13 Hz activity over occipital regions
  2. Runs of 2-6 Hz sawtooth waves occurring in REM sleep
  3. High-amplitude biphasic waves with an initial negative deflection followed by a positive component Correct answer.
  4. Brief bursts of 11-16 Hz activity lasting 0.5-1.5 seconds

Explanation

A K-complex is a well-delineated negative sharp wave immediately followed by a positive component lasting at least 0.5 seconds. It is a defining feature of N2 sleep and may be evoked by stimuli.

Question 4Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which neurotransmitter is released by neurons of the ventrolateral preoptic area to promote sleep?

  1. Histamine
  2. GABA Correct answer.
  3. Orexin (hypocretin)
  4. Acetylcholine

Explanation

VLPO neurons are GABAergic (often co-releasing galanin) and inhibit wake-promoting arousal nuclei. Orexin and histamine promote wakefulness, and acetylcholine supports cortical activation.

Question 5Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

According to the reciprocal interaction (flip-flop) model of sleep-wake control, what stabilizes the switch between sleep and wake states?

  1. Direct inhibition of the SCN by the thalamus
  2. Independent oscillation of cortical neurons without subcortical input
  3. Continuous cholinergic tone from the pedunculopontine nucleus
  4. Mutual inhibition between VLPO and arousal nuclei reinforced by orexin Correct answer.

Explanation

The flip-flop model proposes mutually inhibitory VLPO and arousal populations, with orexin stabilizing the wake state and preventing unwanted transitions. Loss of orexin destabilizes the switch, as seen in narcolepsy.

Question 6Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

The suprachiasmatic nucleus generates circadian rhythmicity primarily because its neurons exhibit which property?

  1. Random firing that is entrained by cerebrospinal fluid glucose
  2. Intrinsic molecular transcriptional-translational feedback loops Correct answer.
  3. Dependence on circulating melatonin for rhythm generation
  4. Light-evoked depolarization independent of retinal input

Explanation

SCN neurons contain cell-autonomous clock gene feedback loops (e.g., CLOCK/BMAL1 and PER/CRY) that generate near-24-hour rhythms even without external input. Light entrains but does not generate the rhythm, and melatonin is an output rather than a driver.

Question 7Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which retinal cell type is most important for transmitting photic information to the suprachiasmatic nucleus for circadian entrainment?

  1. Horizontal cells
  2. Cones
  3. Rods
  4. Melanopsin-containing intrinsically photosensitive retinal ganglion cells Correct answer.

Explanation

ipRGCs containing melanopsin project via the retinohypothalamic tract to the SCN and mediate non-image-forming light responses such as entrainment. Rods and cones contribute to image formation and can modulate but are not the primary conduit.

Question 8Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

A traveler flies from New York to Tokyo and experiences circadian misalignment. Which direction of travel generally produces a phase advance requiring the fewest days to adapt?

  1. Northward travel
  2. Eastward travel
  3. Westward travel Correct answer.
  4. Adaptation time is identical in all directions

Explanation

The human circadian period is slightly longer than 24 hours, so phase delays are easier to achieve than phase advances. Westward travel requires delays and typically adapts faster than eastward travel, which requires advances.

Question 9Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Light exposure in the early biological night typically produces which effect on circadian phase?

  1. Phase advance
  2. No phase effect
  3. Permanent arrhythmicity
  4. Phase delay Correct answer.

Explanation

Light before the core body temperature minimum (early biological night) delays the clock, whereas light after the temperature minimum advances it. This phase response curve underlies light therapy timing.

Question 10Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

In normally entrained humans, core body temperature reaches its minimum at approximately what circadian phase?

  1. At the midpoint of the sleep episode
  2. At habitual bedtime
  3. About 2 hours before habitual wake time Correct answer.
  4. About 6 hours after habitual wake time

Explanation

The core temperature minimum occurs in the latter part of the habitual sleep episode, roughly 2 hours before awakening. It serves as a practical marker of circadian phase for timing light and melatonin.

Question 11Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which statement best describes the typical distribution of REM sleep across a full night of sleep in a healthy young adult?

  1. REM is concentrated in the first third of the night
  2. REM periods lengthen progressively, predominating in the final third Correct answer.
  3. REM is absent until the fourth sleep cycle
  4. REM occurs in equal amounts in every sleep cycle

Explanation

REM sleep episodes are short early in the night and lengthen across successive cycles, so most REM occurs in the last third. Slow-wave sleep shows the opposite pattern, predominating early.

Question 12Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

In a healthy adult, the first episode of REM sleep usually occurs after approximately how long following sleep onset?

  1. 5-10 minutes
  2. 150-180 minutes
  3. 20-30 minutes
  4. 60-90 minutes Correct answer.

Explanation

Normal sleep architecture progresses N1, N2, N3, then REM, with the first REM period typically appearing about 60-90 minutes after sleep onset. Earlier REM onset (sleep-onset REM) suggests pathology such as narcolepsy or severe sleep deprivation.

Question 13Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which change in sleep architecture is most characteristic of normal aging in older adults?

  1. Increased number and duration of awakenings after sleep onset Correct answer.
  2. Increased percentage of slow-wave sleep
  3. Earlier first REM period with markedly prolonged REM
  4. Longer total sleep time

Explanation

Aging is associated with more fragmented sleep, including increased awakenings and wake after sleep onset, along with reduced slow-wave sleep. Total sleep time tends to decline modestly rather than increase.

Question 14Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

At what age does the EEG pattern of sleep begin to show recognizable sleep spindles in typically developing infants?

  1. At birth
  2. Around 2-3 months Correct answer.
  3. After 3 years
  4. Around 6-12 months

Explanation

Sleep spindles generally emerge around 2-3 months of age as thalamocortical circuits mature, allowing N2-like features to be scored. Neonatal EEG lacks well-formed spindles.

Question 15Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which feature distinguishes REM sleep from NREM sleep on polysomnography?

  1. Vertex sharp waves in the central derivations
  2. Presence of sleep spindles
  3. Low chin EMG tone with rapid eye movements and mixed-frequency EEG Correct answer.
  4. High-amplitude delta waves occupying most of the epoch

Explanation

REM is defined by low-amplitude mixed-frequency EEG, episodic rapid eye movements, and atonia reflected in low chin EMG. Spindles, delta waves, and vertex sharp waves are NREM features.

Question 16Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

A patient's polysomnogram shows an epoch with low-amplitude mixed-frequency EEG, no rapid eye movements, and chin EMG tone that is higher than in REM but lower than wakefulness. Which stage is most likely?

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

Explanation

N1 is characterized by low-amplitude mixed-frequency EEG, slow eye movements, and EMG tone below wake but above REM, without spindles or K-complexes. Absence of spindles/K-complexes argues against N2, and absent REMs with preserved tone argues against stage R.

Question 17Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which of the following best explains why the circadian system can be entrained to a 24-hour day despite an intrinsic period slightly longer than 24 hours?

  1. The SCN gradually loses rhythmicity after birth
  2. Melatonin directly resets the SCN each morning
  3. Daily phase shifts from light exposure reset the clock Correct answer.
  4. Sleep pressure overrides circadian timing nightly

Explanation

Because the free-running period is slightly longer than 24 hours, daily light-induced phase advances keep the clock aligned with the solar day. Melatonin can influence timing but is not the primary daily resetting signal in sighted individuals.

Question 18Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Two-process model predictions: after a night of total sleep deprivation, which combination best describes the expected changes?

  1. Increased homeostatic sleep pressure with continued circadian modulation of alertness Correct answer.
  2. Decreased homeostatic pressure with loss of circadian variation
  3. Unchanged homeostatic pressure with increased circadian amplitude
  4. Reduced slow-wave sleep on the recovery night

Explanation

The two-process model holds that wakefulness builds homeostatic sleep pressure (Process S) while circadian Process C modulates alertness. Deprivation raises Process S, and recovery sleep shows increased slow-wave activity.

Question 19Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

Which best describes the normal pattern of melatonin secretion in an entrained individual?

  1. Constant throughout the 24-hour day
  2. Peaking at the core body temperature minimum
  3. High during the day and low at night
  4. Low during the day and rising in the evening before habitual bedtime Correct answer.

Explanation

Melatonin is suppressed by light and rises in the evening under SCN control, with dim-light melatonin onset typically occurring a couple of hours before habitual bedtime. Levels are low during the day and are not constant.

Question 20Normal Sleep and Sleep-Wake Mechanisms (neurobiology, circadian rhythms, ontogeny)

A researcher observes that eliminating orexin neurons in an animal produces sudden transitions between wakefulness and REM-like sleep. This finding most directly supports which concept?

  1. Orexin stabilizes wakefulness and prevents inappropriate state transitions Correct answer.
  2. Orexin directly drives REM atonia
  3. Orexin is the primary generator of slow-wave sleep
  4. Orexin is required for circadian entrainment

Explanation

Orexin stabilizes the wake state within the flip-flop switch; its loss causes unstable transitions and sleep-onset REM, as in narcolepsy. It does not generate slow-wave sleep, drive atonia, or mediate photic entrainment.

Question 21Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A polysomnogram shows a 30-second epoch in which the EEG contains sleep spindles and K-complexes but no slow waves, with low chin EMG tone and no rapid eye movements. Which stage should be scored?

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

Explanation

Stage N2 is defined by the presence of sleep spindles or K-complexes in the absence of the slow-wave criteria for N3 and without REM features. Low chin tone alone does not make the epoch REM, and N1 lacks spindles and K-complexes.

Question 22Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which measure from a diagnostic polysomnogram is used to define obstructive sleep apnea severity for adults?

  1. Periodic limb movement index
  2. Oxygen desaturation index
  3. Arousal index
  4. Apnea-hypopnea index Correct answer.

Explanation

The apnea-hypopnea index (events per hour of sleep) is the standard metric for classifying obstructive sleep apnea severity as mild, moderate, or severe. The other indices describe different phenomena and are not used for OSA severity grading.

Question 23Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A multiple sleep latency test is being planned for a patient suspected of narcolepsy. Which instruction is essential for valid results?

  1. Schedule the test in the late evening to capture circadian lows
  2. Allow the patient to sleep freely between nap opportunities
  3. Perform the test immediately after a night of total sleep deprivation
  4. Discontinue caffeine and stimulants before testing and keep a sleep log for the prior one to two weeks Correct answer.

Explanation

The MSLT requires adequate prior sleep, a sleep diary, and discontinuation of stimulants and REM-suppressing medications so that results are not confounded. Testing follows an overnight polysomnogram and is performed in the morning at two-hour intervals.

Question 24Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which questionnaire is most appropriate for screening a patient for restless legs syndrome?

  1. Epworth Sleepiness Scale
  2. Insomnia Severity Index
  3. STOP-BANG questionnaire
  4. Cambridge-Hopkins RLS questionnaire Correct answer.

Explanation

The Cambridge-Hopkins questionnaire was designed to identify the four essential diagnostic criteria for restless legs syndrome. The other instruments screen for sleepiness, obstructive sleep apnea risk, and insomnia severity respectively.

Question 25Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

During a maintenance of wakefulness test, the patient is instructed to do which of the following?

  1. Walk on a treadmill while being monitored
  2. Complete a reaction-time task on a computer
  3. Remain awake while sitting quietly in a dimly lit room Correct answer.
  4. Fall asleep as quickly as possible in a dark room

Explanation

The MWT measures the ability to stay awake; the patient sits in a quiet, dimly lit room and is told to remain awake during each trial. The MSLT, by contrast, asks the patient to try to fall asleep.

Question 26Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which parameter is a standard measure of sleep fragmentation derived from polysomnography?

  1. Sleep efficiency
  2. Total sleep time
  3. Apnea-hypopnea index
  4. Arousal index Correct answer.

Explanation

The arousal index counts EEG arousals per hour of sleep and directly quantifies fragmentation. Total sleep time and sleep efficiency describe sleep quantity and continuity, while the apnea-hypopnea index quantifies respiratory events.

Question 27Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which finding on a diagnostic polysomnogram is a hallmark of REM sleep?

  1. Sawtooth waves with rapid eye movements and low chin EMG tone Correct answer.
  2. High-amplitude slow waves occupying most of the epoch
  3. Sleep spindles occurring in the first sleep cycle
  4. Vertex sharp waves appearing at sleep onset

Explanation

REM sleep is characterized by low-amplitude mixed-frequency EEG, rapid eye movements, low chin EMG tone, and sometimes sawtooth waves. Spindles define N2, slow waves define N3, and vertex sharp waves are typical of N1.

Question 28Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient reports excessive daytime sleepiness and the clinician wants a simple, validated self-report measure of general daytime sleep propensity over recent weeks. Which instrument is best suited?

  1. Morningness-Eveningness Questionnaire
  2. Pittsburgh Sleep Quality Index
  3. Epworth Sleepiness Scale Correct answer.
  4. Stanford Sleepiness Scale

Explanation

The Epworth Sleepiness Scale asks about the likelihood of dozing in eight situations and is the standard measure of general daytime sleep propensity. The Stanford scale captures momentary sleepiness, the PSQI assesses sleep quality, and the MEQ assesses chronotype.

Question 29Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

An actigraphy study in a patient with suspected insomnia shows high sleep efficiency and a long total sleep time, but the patient reports severe insomnia. What is the most likely explanation for this discrepancy?

  1. The patient has undiagnosed narcolepsy with sleep-onset REM
  2. The patient is underestimating sleep time, a common feature of paradoxical insomnia Correct answer.
  3. The actigraph is overcounting wake time because of poor sensitivity
  4. The actigraphy was recorded during a night of sleep deprivation

Explanation

In paradoxical (sleep-state misperception) insomnia, objective sleep measures such as actigraphy or polysomnography indicate relatively normal sleep while the patient reports marked insomnia. This mismatch is characteristic of the condition rather than device malfunction.

Question 30Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A polysomnogram in an adult shows a 25-second respiratory event with a 40% reduction in airflow, an associated 4% oxygen desaturation, and a cortical arousal. How should this event be scored?

  1. Central apnea
  2. Obstructive apnea
  3. Hypopnea Correct answer.
  4. Respiratory effort-related arousal

Explanation

A hypopnea requires a reduction in airflow lasting at least 10 seconds with either a 3% or greater desaturation or an arousal, depending on the scoring criteria used. The event does not meet the 90% or greater airflow reduction required for an apnea.

Question 31Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient with suspected narcolepsy has an MSLT showing a mean sleep latency of 6 minutes and two sleep-onset REM periods. Which additional finding is most consistent with a diagnosis of narcolepsy type 1?

  1. Elevated serum ferritin
  2. Prolonged REM latency on the preceding polysomnogram
  3. Low cerebrospinal fluid hypocretin-1 level Correct answer.
  4. Increased periodic limb movements in sleep

Explanation

Narcolepsy type 1 is associated with hypocretin deficiency, reflected by low cerebrospinal fluid hypocretin-1. A prolonged REM latency and elevated ferritin are not features of narcolepsy type 1.

Question 32Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which finding on a polysomnogram most strongly suggests that a respiratory event is obstructive rather than central?

  1. A gradual decrease in oxygen saturation before the event
  2. Absence of thoracoabdominal effort throughout the event
  3. An event occurring predominantly during REM sleep
  4. Continued or increasing thoracoabdominal effort during the airflow reduction Correct answer.

Explanation

Preserved or increasing respiratory effort during an airflow reduction indicates an obstructive mechanism. Central events are characterized by absent effort, and REM predominance or gradual desaturation does not by itself distinguish the two.

Question 33Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient is being evaluated for possible shift work disorder. Which actigraphy finding best supports the diagnosis?

  1. Normal sleep duration and timing on workdays with no daytime symptoms
  2. A sleep-wake pattern that is misaligned with the work schedule and shows reduced sleep during scheduled sleep periods Correct answer.
  3. A consistently advanced sleep phase relative to the desired schedule
  4. Frequent nighttime awakenings with normal total sleep time

Explanation

Shift work disorder is characterized by insomnia or excessive sleepiness temporally associated with a work schedule that overlaps the usual sleep period, with actigraphy showing misalignment and shortened sleep. A normal pattern would not support the diagnosis.

Question 34Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

During polysomnography, an epoch contains 22% of the epoch occupied by waves of 0.5-2 Hz with peak-to-peak amplitude greater than 75 microvolts. How should this epoch be scored?

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

Explanation

Stage N3 is scored when slow waves of 0.5-2 Hz and greater than 75 microvolts occupy at least 20% of the epoch. Because 22% exceeds the threshold, the epoch qualifies as N3.

Question 35Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which physical examination finding is most suggestive of a high risk for obstructive sleep apnea in an adult?

  1. Mallampati class IV oropharynx with a crowded posterior airway Correct answer.
  2. Bilateral tonsillar hypertrophy in a young child
  3. Body mass index of 22 kg/m2 with a thin neck
  4. A small, recessed mandible with a normal airway

Explanation

A high Mallampati score with a crowded oropharynx indicates a narrow upper airway and raises the risk of obstructive sleep apnea. Low BMI and a thin neck are associated with lower risk.

Question 36Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient with excessive daytime sleepiness has an MSLT mean sleep latency of 12 minutes and no sleep-onset REM periods. How should these results be interpreted?

  1. The findings confirm narcolepsy type 2
  2. The findings are not diagnostic of narcolepsy and alternative causes of sleepiness should be evaluated Correct answer.
  3. The findings are invalid and must be repeated immediately
  4. The findings confirm idiopathic hypersomnia

Explanation

A mean sleep latency of 12 minutes is within the normal range and no sleep-onset REM periods were observed, so the study does not support narcolepsy or idiopathic hypersomnia. Alternative causes of sleepiness, such as insufficient sleep or sleep apnea, should be considered.

Question 37Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which polysomnographic finding is most consistent with REM sleep behavior disorder?

  1. Excessive chin EMG tone during REM sleep with dream-enactment behaviors Correct answer.
  2. Prolonged REM latency with normal chin tone
  3. Absent rapid eye movements during REM sleep
  4. Frequent sleep spindles during REM sleep

Explanation

REM sleep behavior disorder is characterized by loss of normal REM atonia, reflected in elevated chin EMG tone during REM, often accompanied by dream enactment. Normal REM atonia would show low chin tone.

Question 38Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A clinician wants to estimate sleep duration and circadian rest-activity patterns over two weeks in a patient who cannot tolerate polysomnography. Which test is most appropriate?

  1. Overnight oximetry
  2. Maintenance of wakefulness test
  3. Multiple sleep latency test
  4. Wrist actigraphy Correct answer.

Explanation

Wrist actigraphy provides continuous, noninvasive estimates of sleep-wake patterns over multiple days and is useful for circadian and sleep-duration assessment. Oximetry assesses oxygenation, and the MSLT and MWT are laboratory daytime tests.

Question 39Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which of the following is a recognized limitation of home sleep apnea testing compared with attended polysomnography?

  1. It cannot detect any respiratory events
  2. It requires electroencephalographic monitoring of sleep stages
  3. It is always more expensive than in-laboratory testing
  4. It may underestimate severity because total sleep time is not measured directly Correct answer.

Explanation

Home sleep apnea testing typically uses recording time rather than sleep time as the denominator, which can underestimate the apnea-hypopnea index and severity. It does not include EEG for staging and is generally less costly than attended polysomnography.

Question 40Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A polysomnogram shows a 15-second event with absent airflow, absent thoracoabdominal effort, and a 5% oxygen desaturation. How should this event be scored?

  1. Hypopnea
  2. Obstructive apnea
  3. Mixed apnea
  4. Central apnea Correct answer.

Explanation

A central apnea is defined by absent airflow for at least 10 seconds with absent respiratory effort. The absence of effort distinguishes it from obstructive and mixed apneas.

Question 41Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

Which scoring rule applies to sleep-onset REM periods during an MSLT?

  1. A sleep-onset REM period is scored when REM sleep occurs at any point during a nap
  2. A sleep-onset REM period is scored when REM sleep occurs within 15 minutes of sleep onset Correct answer.
  3. A sleep-onset REM period is scored only when it occurs in the first nap
  4. A sleep-onset REM period is scored only when REM sleep occurs within 5 minutes of sleep onset

Explanation

For MSLT interpretation, a sleep-onset REM period is defined as REM sleep occurring within 15 minutes of sleep onset in a nap. The number of such periods across naps, not just the first nap, contributes to interpretation.

Question 42Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient with obesity and daytime sleepiness has a polysomnogram showing an apnea-hypopnea index of 12 events per hour with a minimum oxygen saturation of 82%. Which statement best characterizes the severity?

  1. Central sleep apnea syndrome
  2. Moderate obstructive sleep apnea by event frequency, with significant nocturnal hypoxemia Correct answer.
  3. Mild obstructive sleep apnea with no clinically relevant desaturation
  4. Severe obstructive sleep apnea by event frequency

Explanation

An apnea-hypopnea index of 12 falls in the moderate range (5-15 is mild, 15-30 is moderate, and greater than 30 is severe), and a nadir saturation of 82% indicates meaningful hypoxemia. Severity classification is based on event frequency, with oxygen saturation providing additional clinical context.

Question 43Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

A patient reports insomnia and the clinician suspects a circadian rhythm disorder. Which combination of findings best supports delayed sleep-wake phase disorder?

  1. Polysomnography showing frequent apneas with desaturations
  2. Actigraphy showing fragmented sleep with reduced total sleep time regardless of schedule
  3. A short MSLT mean sleep latency with sleep-onset REM periods
  4. Actigraphy showing a consistently delayed sleep midpoint with normal sleep duration when allowed to sleep on the preferred schedule Correct answer.

Explanation

Delayed sleep-wake phase disorder is characterized by a stable delay in the sleep-wake timing relative to the desired schedule, with normal sleep duration when the person can follow their preferred schedule. Actigraphy over multiple days best demonstrates this pattern.

Question 44Sleep Evaluation and Testing (history, physical, polysomnography, MSLT/MWT, actigraphy, questionnaires)

During polysomnography, a patient shows a sequence of increasing respiratory effort followed by a cortical arousal without meeting criteria for an apnea or hypopnea. How should this be scored?

  1. Respiratory effort-related arousal Correct answer.
  2. Central apnea
  3. Hypopnea
  4. Obstructive apnea

Explanation

A respiratory effort-related arousal is scored when increasing respiratory effort leads to an arousal without satisfying apnea or hypopnea criteria. It reflects increased upper airway resistance rather than complete or partial airflow reduction meeting event thresholds.

Question 45Insomnia (diagnosis, behavioral and pharmacologic management)

Which instrument is the standard structured diagnostic interview for insomnia disorder in clinical research?

  1. Pittsburgh Sleep Quality Index
  2. Epworth Sleepiness Scale
  3. Insomnia Severity Index
  4. Duke Structured Interview for Sleep Disorders Correct answer.

Explanation

The Duke Structured Interview for Sleep Disorders applies DSM/ICSD criteria in a structured format and is used to establish insomnia disorder diagnoses. Questionnaires like the ISI and PSQI measure severity or quality rather than rendering a diagnosis.

Question 46Insomnia (diagnosis, behavioral and pharmacologic management)

A patient reports lying awake for about 90 minutes most nights despite adequate time in bed and feeling unrefreshed. Which finding best supports insomnia disorder rather than insufficient sleep syndrome?

  1. Habitual short sleep with voluntary bedtime restriction
  2. Prolonged sleep duration on free days
  3. Elevated multiple sleep latency test mean
  4. Complaints of sleep-onset difficulty with adequate opportunity to sleep Correct answer.

Explanation

Insomnia disorder requires sleep difficulty despite adequate opportunity and circumstances for sleep, plus daytime consequences. Insufficient sleep syndrome instead reflects voluntarily curtailed sleep that resolves with extended sleep opportunity.

Question 47Insomnia (diagnosis, behavioral and pharmacologic management)

Which polysomnographic finding is most characteristic of psychophysiological insomnia?

  1. Sleep-onset REM periods
  2. Frequent apneas with oxyhemoglobin desaturations
  3. Periodic limb movements in sleep
  4. Prolonged sleep latency with reduced sleep efficiency Correct answer.

Explanation

Psychophysiological insomnia shows objective prolongation of sleep latency and poor sleep efficiency, often worse than the patient's subjective report suggests. PSG is not required for diagnosis but can support it.

Question 48Insomnia (diagnosis, behavioral and pharmacologic management)

Stimulus control therapy for insomnia is based on which principle?

  1. Reducing physiologic arousal through progressive muscle relaxation
  2. Limiting time in bed to the patient's estimated total sleep time
  3. Challenging catastrophic beliefs about the consequences of poor sleep
  4. Reinforcing the bed as a cue for sleep by restricting it to sleep and intimacy Correct answer.

Explanation

Stimulus control re-establishes the bed as a discriminative stimulus for sleep by pairing it only with sleep and sexual activity and by leaving the bed when unable to sleep. It also standardizes wake time and forbids daytime napping.

Question 49Insomnia (diagnosis, behavioral and pharmacologic management)

A patient beginning sleep restriction therapy is prescribed a 5-hour time-in-bed window. What is the standard rule for adjusting the window?

  1. Extend by 60 minutes whenever the patient feels tired
  2. Extend by 30 minutes when sleep efficiency exceeds 85-90% Correct answer.
  3. Shorten it weekly until the patient reports no awakenings
  4. Keep it fixed for at least six months regardless of efficiency

Explanation

Sleep restriction titrates time in bed using sleep efficiency, typically extending by 15-30 minutes when efficiency exceeds about 85-90% and shortening when it falls below about 80-85%. The prescribed window should never fall below the patient's individual minimum, usually around 5 hours.

Question 50Insomnia (diagnosis, behavioral and pharmacologic management)

Which agent is approved by the FDA specifically for sleep-maintenance insomnia and is a controlled substance?

  1. Diphenhydramine
  2. Suvorexant
  3. Zolpidem extended-release Correct answer.
  4. Melatonin

Explanation

Zolpidem extended-release is a Schedule IV agent approved for sleep onset and maintenance. Suvorexant is a Schedule IV orexin antagonist approved for onset and maintenance but is not a GABA-A hypnotic.