ABIM Sleep Medicine flashcards

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

K-complex

A negative sharp wave followed by a positive component lasting ≥0.5 seconds, seen in NREM stage N2 sleep; often elicited by stimuli and a hallmark of N2.

Sleep spindle

A train of 11-16 Hz waves lasting ≥0.5 seconds during NREM stage N2 sleep; generated by thalamocortical networks and associated with memory consolidation.

Slow-wave sleep

NREM stage N3, defined by ≥20% of an epoch containing delta waves (0.5-2 Hz, >75 µV); predominates in the first third of the night and declines with age.

REM sleep atonia

Lowest chin EMG tone during REM sleep due to active inhibition of motor neurons; loss of atonia underlies REM sleep behavior disorder.

Two-process model

Sleep regulation model combining homeostatic sleep pressure (Process S) that rises with wakefulness and circadian alerting signal (Process C) that opposes sleep pressure.

Stimulus control therapy

Insomnia treatment using bed only for sleep and sex, going to bed only when sleepy, leaving bed if awake >20 minutes, and maintaining a fixed wake time.

Sleep restriction therapy

Limiting time in bed to average total sleep time (not <5-6 hours), then extending by 15-30 minutes weekly as sleep efficiency exceeds 85-90%.

Sleep efficiency

Total sleep time divided by time in bed, multiplied by 100; target ≥85-90% during sleep restriction therapy for insomnia.

CBT-I first-line

Cognitive behavioral therapy for insomnia is recommended as initial treatment for chronic insomnia, with components including stimulus control, sleep restriction, and cognitive restructuring.

Apnea definition

A ≥90% reduction in airflow lasting ≥10 seconds; central if respiratory effort is absent, obstructive if effort persists, mixed if central then obstructive.

Hypopnea definition

A ≥30% reduction in airflow lasting ≥10 seconds with ≥3% oxygen desaturation or an arousal; used to calculate the apnea-hypopnea index.

STOP-BANG score

Screening tool for obstructive sleep apnea: Snoring, Tiredness, Observed apnea, Pressure (hypertension), BMI >35, Age >50, Neck >40 cm, Gender male; score ≥3 indicates high risk.

PAP adherence

Use of positive airway pressure for ≥4 hours per night on ≥70% of nights; below this threshold is considered poor adherence and warrants intervention.

Obesity hypoventilation syndrome

BMI ≥30, daytime PaCO2 ≥45 mmHg, and sleep-disordered breathing without other cause; treated with PAP (often BiPAP) and weight loss.

Narcolepsy type 1

Excessive daytime sleepiness with cataplexy and/or CSF hypocretin-1 ≤110 pg/mL; caused by loss of hypocretin-producing neurons.

MSLT criteria narcolepsy

Mean sleep latency ≤8 minutes and ≥2 sleep-onset REM periods across 5 naps; a preceding nocturnal SOREMP can substitute for one SOREMP.

Cataplexy

Sudden loss of muscle tone triggered by emotions, typically with preserved consciousness; a hallmark of narcolepsy type 1.

Idiopathic hypersomnia

Excessive daytime sleepiness with MSLT mean sleep latency ≤8 minutes and <2 SOREMPs, or total 24-hour sleep ≥11 hours; no cataplexy.

CSF hypocretin-1

Level ≤110 pg/mL is diagnostic of narcolepsy type 1; normal in narcolepsy type 2 and idiopathic hypersomnia; measured by lumbar puncture.

Delayed sleep-wake phase

Circadian rhythm disorder with sleep onset and wake times delayed ≥2 hours relative to desired times; common in adolescents; treated with morning bright light and evening melatonin.

Advanced sleep-wake phase

Circadian rhythm disorder with sleep onset and wake times advanced, often with early-morning awakening; more common in older adults; treated with evening bright light and morning melatonin.

Non-24-hour rhythm disorder

Circadian period not entrained to 24 hours, most common in totally blind individuals; treated with timed melatonin.

DLMO

Dim light melatonin onset, a marker of circadian phase measured in saliva or plasma under dim light; used to assess circadian rhythm disorders.

REM sleep behavior disorder

Dream enactment with loss of REM atonia; polysomnography shows REM without atonia; strongly associated with synucleinopathies; treated with melatonin or clonazepam.

Sleep terrors

Abrupt arousal from slow-wave sleep with scream, autonomic surge, and confusion; usually no recall; common in children and often resolves spontaneously.

Restless legs syndrome

Urge to move legs, worse at rest and evening/night, relieved by movement; clinical diagnosis; check ferritin and treat if <75-100 ng/mL with iron.

Periodic limb movements

Repetitive limb movements (≥4 consecutive, 5-90 seconds apart) on polysomnography; PLMS index >15/hour in adults is abnormal; not all require treatment.

Depression and insomnia

Bidirectionally associated; CBT-I improves both insomnia and depressive symptoms; screen and treat both concurrently.

ASV contraindication

Adaptive servo-ventilation is contraindicated in symptomatic heart failure with reduced ejection fraction (LVEF ≤45%) due to increased mortality.

Pediatric OSA treatment

Adenotonsillectomy is first-line for most children with obstructive sleep apnea and adenotonsillar hypertrophy; PSG AHI ≥1/hour may be abnormal.

Home sleep apnea testing

Appropriate for adults with high pretest probability of moderate-severe OSA without significant comorbidity; not for children, suspected central apnea, or severe cardiorespiratory disease.

Maintenance of wakefulness test

Measures ability to stay awake in a quiet, dimly lit room; used to assess treatment response in narcolepsy or OSA; mean latency <8 minutes is abnormal.