ABPN Sleep Medicine flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Process S

Homeostatic sleep pressure that builds during wakefulness and dissipates during sleep; modeled as an exponential rise and decay, interacting with circadian Process C.

Orexin (hypocretin)

Lateral hypothalamic neuropeptide that stabilizes wakefulness and suppresses REM; deficiency causes narcolepsy type 1 with cataplexy.

Sleep spindle

11–16 Hz burst lasting ≥0.5 seconds in N2 sleep, generated by thalamocortical circuits; marker of sleep maintenance and memory consolidation.

K-complex

Negative sharp wave followed by positive slow wave lasting ≥0.5 seconds, a hallmark of N2 sleep; can be evoked by stimuli.

Apnea-hypopnea index

Number of apneas plus hypopneas per hour of sleep; ≥5 with symptoms or ≥15 alone defines obstructive sleep apnea.

SOREMP

Sleep-onset REM period, defined as REM latency ≤15 minutes on PSG or MSLT; two or more support narcolepsy diagnosis.

MSLT protocol

Four to five naps at 2-hour intervals after overnight PSG; records mean sleep latency and SOREMPs to evaluate central hypersomnia.

Maintenance of Wakefulness Test

Four 40-minute trials at 2-hour intervals while seated in dim light; mean sleep latency ≤8 minutes indicates excessive sleepiness.

Actigraphy

Wrist-worn accelerometer estimating rest-activity cycles over days to weeks; useful for circadian disorders, insomnia patterns, and total sleep time.

CBT-I

Multicomponent first-line insomnia therapy combining sleep restriction, stimulus control, cognitive restructuring, sleep hygiene, and relaxation; benefits persist after treatment.

Stimulus control

Behavioral rule set: bed only for sleep and intimacy, leave bed if awake >20 minutes, and maintain a fixed wake time.

Sleep restriction therapy

Limits time in bed to average total sleep time, then extends by 15–30 minutes weekly as sleep efficiency exceeds 85–90%.

DORA

Dual orexin receptor antagonist (suvorexant, lemborexant, daridorexant) used for sleep maintenance insomnia; contraindicated in narcolepsy.

Augmentation

Worsening of restless legs symptoms with dopaminergic therapy, with earlier onset, greater intensity, and spread to other body parts.

PLMS index

Periodic limb movements per hour of sleep; ≥15 in adults is considered elevated, though asymptomatic PLMS do not require treatment.

RLS diagnostic criteria

Urge to move legs, worse at rest, relieved by movement, and worse in the evening; diagnosis is clinical, not by polysomnography.

Cheyne-Stokes respiration

Crescendo-decrescendo breathing with central apneas, seen in heart failure due to prolonged circulation time and loop gain instability.

Obesity hypoventilation

BMI ≥30 with daytime PaCO2 ≥45 mmHg during wakefulness and sleep-disordered breathing, without another cause of hypoventilation.

Treatment-emergent central apnea

Central apneas appearing when PAP eliminates obstructive events; often resolves with continued therapy and may need ASV or BPAP.

PHOX2B

Gene mutated in congenital central hypoventilation syndrome, causing impaired chemosensitivity and sleep-related alveolar hypoventilation.

Cataplexy

Sudden bilateral loss of muscle tone triggered by emotion with preserved consciousness; hallmark of narcolepsy type 1.

Kleine-Levin syndrome

Recurrent episodes of hypersomnia with cognitive disturbances and hyperphagia or hypersexuality, typically in adolescent males, with normal function between episodes.

Idiopathic hypersomnia

Excessive daytime sleepiness with long unrefreshing naps, prolonged sleep, no cataplexy, and ≤1 SOREMP on MSLT.

Delayed sleep-wake phase

Sleep onset and offset delayed ≥2 hours beyond conventional times; common in adolescents; treat with morning light and evening melatonin.

Non-24-hour rhythm disorder

Free-running circadian rhythm, especially in blind individuals lacking photic entrainment; melatonin or tasimelteon may entrain the clock.

Jet lag disorder

Transient insomnia and sleepiness after transmeridian travel; eastward travel requires phase advance and is generally harder to adapt to.

REM sleep behavior disorder

Dream enactment with loss of REM atonia; strongly associated with synucleinopathies and treated with melatonin or clonazepam.

Sleep terrors

Abrupt arousal from N3 sleep with autonomic surge, inconsolable crying, and amnesia; common in children and usually self-limited.

Nightmare disorder

REM-related frightening dreams causing full awakening with recall; imagery rehearsal therapy and prazosin are evidence-based treatments.

REM latency in depression

Depression shortens REM latency and increases REM density while reducing slow-wave sleep; insomnia is a risk factor for incident depression.

Nocturnal hypoxemia in COPD

Oxygen desaturation from hypoventilation and V/Q mismatch in sleep; supplemental oxygen alone may worsen hypercapnia without ventilatory support.

Pediatric OSA surgery threshold

Adenotonsillectomy is first-line for pediatric OSA; AHI ≥10 or oxygen nadir <90% often prompts surgery.