ABP Sleep Medicine cheat sheet

NREM stages N1, N2, N3 and REM cycle roughly every 90 minutes, with 4-6 cycles per night.

N1: theta activity, slow eye movements, vertex sharp waves; loss of alpha marks sleep onset.

N2: sleep spindles (11-16 Hz) and K-complexes are defining features.

N3: slow-wave activity (0.5-2 Hz, >75 microvolts) occupies at least 20% of an epoch.

REM: low-voltage mixed-frequency EEG, rapid eye movements, and skeletal muscle atonia with REMs.

Homeostatic sleep pressure is modeled by Process S; circadian timing is Process C (suprachiasmatic nucleus).

Melatonin secretion from the pineal rises in dim light and is suppressed by bright light.

Adenosine accumulates with wakefulness and is a key homeostatic sleep-promoting signal.

Slow-wave sleep predominates in the first third of the night; REM predominates in the last third.

OSA diagnosis: AHI >=5 with symptoms, or AHI >=15 regardless of symptoms.

Hypopnea: >=30% airflow reduction with >=3% desaturation or an arousal (AASM scoring rules).

Obstructive apnea: >=90% airflow reduction with continued inspiratory effort.

Central apnea: >=90% airflow reduction with absent inspiratory effort for >=10 seconds.

OSA severity: mild AHI 5-15, moderate 15-30, severe >30 events per hour.

First-line therapy for OSA is positive airway pressure (CPAP); alternatives include oral appliances and positional therapy.

Obesity hypoventilation: BMI >=30 with awake PaCO2 >45 mmHg in the absence of other causes.

Central sleep apnea with Cheyne-Stokes respiration is common in heart failure with reduced ejection fraction.

Insomnia disorder requires difficulty initiating or maintaining sleep with daytime impairment >=3 nights/week for >=3 months.

Cognitive behavioral therapy for insomnia (CBT-I) is first-line treatment for chronic insomnia.

Stimulus control: use the bed only for sleep and intimacy, leave bed if awake, and keep a fixed wake time.

Sleep restriction therapy limits time in bed to the estimated total sleep time, then titrates upward.

Paradoxical insomnia (sleep state misperception) shows a discrepancy between reported and objective sleep.

Benzodiazepine receptor agonists shorten sleep latency but carry dependence and tolerance risk.

Low-dose doxepin and ramelteon are FDA-approved for insomnia with limited dependence liability.

Insomnia frequently coexists with depression and anxiety; treat the comorbid condition concurrently.

Narcolepsy type 1: cataplexy plus CSF hypocretin-1 <=110 pg/mL, or low hypocretin with short sleep latency.

Narcolepsy type 2: excessive daytime sleepiness with MSLT mean sleep latency <=8 minutes and >=2 SOREMPs, without cataplexy.

MSLT: mean sleep latency <=8 minutes is abnormal; a SOREMP is REM onset within 15 minutes of sleep onset.

A SOREMP on the preceding polysomnogram (REM within 15 minutes) can substitute for one MSLT SOREMP.

Idiopathic hypersomnia: MSLT mean sleep latency <=8 minutes with fewer than 2 SOREMPs and no cataplexy.

Kleine-Levin syndrome: recurrent episodes of hypersomnia with cognitive and behavioral changes.

Narcolepsy type 1 reflects loss of hypocretin-producing neurons in the lateral hypothalamus.

Modafinil, sodium oxybate, and stimulants are used for narcolepsy; sodium oxybate reduces cataplexy.

Delayed sleep-wake phase disorder: sleep-wake timing is delayed >=2 hours relative to desired/required schedule.

Advanced sleep-wake phase disorder: early sleep onset and early awakening, common in older adults.

Shift work disorder: insomnia or excessive sleepiness temporally linked to work schedule.

Jet lag disorder: transient misalignment after rapid travel across >=2 time zones.

Non-24-hour sleep-wake rhythm disorder: free-running rhythm, common in totally blind individuals.

Dim light melatonin onset (DLMO) is a marker of circadian phase; typical DLMO occurs ~2 hours before sleep.

Morning bright light and evening melatonin advance circadian phase; evening light delays it.

Irregular sleep-wake rhythm shows no discernible circadian pattern, often in dementia or institutionalized patients.

NREM parasomnias (confusional arousals, sleepwalking, sleep terrors) arise from slow-wave sleep, often in the first third of the night.

REM sleep behavior disorder (RBD) involves dream enactment with loss of REM atonia and elevated chin EMG.

RBD is associated with synucleinopathies (Parkinson disease, Lewy body dementia, multiple system atrophy).

Sleep terrors: abrupt arousal with screaming, autonomic surge, and amnesia for the event.

Nightmare disorder: frightening dreams recalled on awakening, typically from REM sleep.

Sleep-related eating disorder and sexsomnia are NREM parasomnias with partial arousal.

Confusional arousals are more common in children and typically benign and self-limited.

Safety measures (bedroom safety, avoiding sleep deprivation and alcohol) reduce NREM parasomnia risk.

Restless legs syndrome (Willis-Ekbom disease): urge to move the legs, worse at rest and in the evening, relieved by movement.

RLS diagnosis requires symptoms that are worse in the evening/night and not explained by another condition.

Periodic limb movements of sleep (PLMS): repetitive limb movements lasting 0.5-10 seconds, every 5-90 seconds.

PLMS index >15 per hour in adults is considered elevated in the appropriate clinical context.

Iron deficiency and low ferritin are common contributors to RLS; ferritin levels guide workup.

Dopamine agonists (pramipexole, ropinirole) treat RLS but risk augmentation with long-term use.

Sleep bruxism: rhythmic masticatory muscle activity during sleep, often with tooth wear.

Rhythmic movement disorder: body rocking or head banging, most common in infants and young children.

Newborns sleep 16-18 hours/day in irregular, polyphasic patterns with abundant active (REM) sleep.

Infants develop circadian rhythmicity around 2-3 months; melatonin secretion matures in the first months.

Recommended sleep: infants 12-16 hours, toddlers 11-14 hours, school-age children 9-12 hours per night.

Adolescents show a physiologic circadian delay, contributing to delayed sleep phase and insufficient sleep.

Obstructive sleep apnea in children commonly presents with adenotonsillar hypertrophy and is often treated with adenotonsillectomy.

Pediatric OSA may present with behavioral problems, inattention, or enuresis rather than daytime sleepiness.

Parasomnias such as sleepwalking and sleep terrors peak in school-age children and usually resolve.

Sudden infant death syndrome risk is reduced by supine sleeping and avoidance of soft bedding.

Polysomnography records EEG, EOG, EMG, ECG, airflow, respiratory effort, oxygen saturation, and body position.

AASM recommends 30-second epochs for scoring sleep stages in adults.

Home sleep apnea testing is used for suspected moderate-to-severe OSA in adults without significant comorbidity.

MSLT consists of 4-5 naps at 2-hour intervals following an overnight polysomnogram.

Maintenance of wakefulness test (MWT) measures ability to stay awake; used for safety-sensitive occupations.

Actigraphy estimates sleep-wake patterns over multiple days and is useful for circadian assessment.

Oximetry alone is insufficient for diagnosing OSA; it is a screening tool.

Chin EMG during PSG helps identify REM atonia and detect REM sleep behavior disorder.