ABA Sleep Medicine cheat sheet

Normal adult sleep architecture: N1 ~5%, N2 ~45-55%, N3 ~15-25%, REM ~20-25% of total sleep time.

Sleep cycles last ~90 minutes; N3 predominates in the first third of the night, REM in the last third.

REM sleep requires low chin EMG tone plus rapid eye movements and mixed-frequency low-amplitude EEG.

Slow-wave sleep is scored when >20% of an epoch shows 0.5-2 Hz waves with peak-to-peak amplitude >75 µV.

Sleep onset latency >30 minutes on multiple nights is abnormal; normal latency is typically 10-20 minutes.

Melatonin secretion peaks in darkness and is suppressed by light; it is a chronobiotic, not a primary hypnotic.

Adenosine accumulates with wakefulness and is cleared during sleep; caffeine antagonizes adenosine receptors.

Total sleep time generally declines with age, and sleep efficiency falls below 85% in many older adults.

Delayed sleep-wake phase disorder: sleep onset and offset >2 hours later than desired, with normal sleep duration when unconstrained.

Advanced sleep-wake phase disorder is more common in older adults and shows early sleep onset and early awakening.

Shift work disorder requires insomnia or excessive sleepiness temporally linked to work schedule for at least 3 months.

Jet lag disorder is transient and resolves as circadian entrainment occurs; eastward travel usually causes more difficulty.

Non-24-hour sleep-wake rhythm disorder is most prevalent in totally blind individuals lacking light entrainment.

Dim light melatonin onset (DLMO) is the standard marker of circadian phase; it normally occurs 2-3 hours before habitual sleep onset.

Morning bright light therapy advances circadian phase; evening light exposure delays it.

Irregular sleep-wake rhythm disorder shows fragmented sleep without a clear circadian pattern, common in dementia.

OSA diagnosis by polysomnography: AHI ≥5 with symptoms, or AHI ≥15 regardless of symptoms.

AHI 5-15 is mild, 15-30 is moderate, and >30 is severe obstructive sleep apnea.

Central sleep apnea is scored when there is absent airflow without respiratory effort; Cheyne-Stokes respiration is a common pattern in heart failure.

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

CPAP is first-line for OSA; adherence is often defined as ≥4 hours per night on ≥70% of nights.

STOP-BANG scores ≥3 indicate elevated OSA risk; it is a screening tool, not diagnostic.

Hypoglossal nerve stimulation is an option for CPAP-intolerant patients with specific anatomic and BMI criteria.

Oral appliances advance the mandible and are most effective for mild to moderate OSA.

Chronic insomnia disorder requires symptoms ≥3 nights per week for ≥3 months with daytime impairment.

CBT-I is first-line treatment for chronic insomnia and includes stimulus control, sleep restriction, and cognitive restructuring.

Sleep restriction therapy limits time in bed to approximate actual total sleep time, then titrates upward as efficiency improves.

Stimulus control instructs leaving the bed when unable to sleep and returning only when sleepy.

Narcolepsy type 1 requires cataplexy or low CSF hypocretin-1 (≤110 pg/mL); type 2 lacks cataplexy and hypocretin deficiency.

Multiple sleep latency test: mean sleep latency ≤8 minutes plus ≥2 sleep-onset REM periods supports narcolepsy.

Idiopathic hypersomnia shows excessive daytime sleepiness without sleep-onset REM periods and often long unrefreshing naps.

Kleine-Levin syndrome is recurrent episodic hypersomnia with cognitive and behavioral changes, often with hyperphagia.

Restless legs syndrome is diagnosed clinically by an urge to move the legs, worse at rest and in the evening, relieved by movement.

Periodic limb movements in sleep are scored when movements last 0.5-10 seconds and occur in series of ≥4.

Iron deficiency is a common contributor to RLS; ferritin levels are checked and iron repletion may be considered.

NREM parasomnias (sleepwalking, sleep terrors) arise mainly from N3 sleep and are common in childhood.

REM sleep behavior disorder involves dream enactment with preserved muscle tone; it is associated with synucleinopathies.

Confusional arousals, sleepwalking, and sleep terrors are disorders of arousal and often familial.

Sleep-related bruxism is characterized by rhythmic masticatory muscle activity, often during N1/N2 sleep.

Safety measures and trigger avoidance are central in managing parasomnias; medications are reserved for dangerous or refractory cases.

Polysomnography records EEG, EOG, chin EMG, ECG, airflow, respiratory effort, oxygen saturation, and limb movements.

The AASM scoring manual defines sleep stages in 30-second epochs; stage N2 begins with a K-complex or sleep spindle.

Home sleep apnea testing is used for adults with high pretest probability of moderate to severe OSA without major comorbidity.

Oxygen desaturation index (ODI) counts desaturations of ≥3% or ≥4% per hour, depending on criteria.

Actigraphy estimates sleep-wake patterns over days to weeks and is useful for circadian and insomnia assessment.

Maintenance of wakefulness test measures ability to stay awake in a quiet setting and is used in safety-sensitive contexts.

Arousals require an abrupt EEG frequency shift lasting ≥3 seconds, with or without EMG increase.

Sleep efficiency equals total sleep time divided by time in bed, expressed as a percentage.

Untreated OSA increases perioperative risk of difficult airway, postoperative desaturation, and cardiopulmonary complications.

Patients with known OSA should be screened preoperatively; CPAP should generally be continued perioperatively when feasible.

Opioids and sedatives can worsen OSA and central apnea by depressing ventilatory drive and airway tone.

Postoperative monitoring for OSA patients includes continuous pulse oximetry and positioning to reduce supine obstruction.

In the ICU, sleep is fragmented with reduced REM and circadian disruption; noise and light contribute.

Delirium risk is increased by sleep deprivation; promoting sleep hygiene and daytime orientation may help.

Obesity hypoventilation patients may need bilevel noninvasive ventilation rather than CPAP alone.

Rapid eye movement sleep rebound after sleep deprivation can worsen obstructive events in the recovery period.

Pregnancy: OSA risk rises with gestational weight gain and edema; supine sleep avoidance is recommended in late pregnancy.

OSA is associated with resistant hypertension, atrial fibrillation, stroke, and heart failure.

In children, OSA is often related to adenotonsillar hypertrophy; adenotonsillectomy is a common first-line treatment.

Pediatric OSA diagnosis uses obstructive apnea-hypopnea index thresholds lower than adult cutoffs (e.g., ≥1-5 events/hour depending on criteria).

In older adults, sleep complaints are common but should not be dismissed as normal aging.

Chronic opioid use can cause central sleep apnea and ataxic breathing.

Depression and insomnia are bidirectionally related; sedating antidepressants may worsen RLS or sleep apnea.

Down syndrome and craniofacial anomalies increase risk of OSA due to anatomic narrowing.