Polysomnography

An overnight polysomnogram (PSG) is an in-lab, technician-supervised, monitored study that serves as the gold standard for diagnosing pediatric obstructive sleep apnea (OSA).
The procedure documents various physiologic variables during sleep, facilitating the accurate measurement of sleep staging, arousals, cardiovascular parameters, and ventilatory abnormalities.
While it is a critical diagnostic tool for specific conditions, a PSG is not routinely warranted for evaluating general childhood sleep problems unless the patient exhibits symptoms suggestive of OSA, periodic limb movements, unusual features of episodic nocturnal events, or unexplained daytime sleepiness.

Polysomnography captures comprehensive data across multiple physiological systems to provide a detailed analysis of sleep architecture and respiratory function.

Parameter Category	Specific Monitors Utilized	Physiologic Variable Assessed
Neurological & Sleep Staging	Electroencephalography (EEG), Electrooculography (EOG), Chin electromyography (EMG)	Sleep staging, arousal measurements, and overall sleep architecture.
Cardiovascular	Electrocardiogram (ECG)	Heart rate and cardiac rhythm stability during sleep.
Respiratory Airflow	Oronasal thermal sensor, Nasal air pressure transducer	Complete (apnea) or partial (hypopnea) cessation of airflow at the nose and/or mouth.
Respiratory Effort & Gas Exchange	Inductance plethysmography (chest/abdominal), Pulse oximeter, End-tidal or transcutaneous CO2 monitor	Respiratory effort, oxygen saturation (hypoxemia), and CO2 retention (hypercapnia).
Movement & Position	Anterior tibialis EMG leads, Body position sensors, Video recording	Leg movements, sleeping posture, and unusual episodic nocturnal behaviors.
Acoustic	Snore microphone	Presence, frequency, and intensity of snoring.

Obstructive Sleep Apnea (OSA): The American Academy of Pediatrics recommends obtaining a PSG for any child or adolescent who regularly snores and exhibits complaints or findings of OSA during routine health maintenance visits.
Post-Operative Evaluation: A follow-up sleep study approximately 6 weeks post-adenotonsillectomy is strongly indicated for high-risk patients (e.g., those with obesity, craniofacial anomalies, Down syndrome, or moderate-to-severe baseline OSA) or in children whose symptoms persist after surgery.
Central Disorders of Hypersomnolence: An overnight PSG followed by a Multiple Sleep Latency Test (MSLT) is required for patients with profound unexplained daytime sleepiness to evaluate for conditions such as narcolepsy and idiopathic hypersomnia. The overnight PSG component is crucial to rule out primary sleep disorders like OSA that could otherwise explain the excessive daytime sleepiness.
Sleep-Related Movement Disorders: For the diagnosis of Periodic Limb Movement Disorder (PLMD), an overnight PSG is necessary to objectively document the characteristic repetitive limb movements using anterior tibialis EMG leads.

Apnea-Hypopnea Index (AHI): The AHI is the most frequently used PSG parameter for evaluating sleep-disordered breathing, as it quantifies the number of apneic and hypopneic events (both obstructive and central) per hour of sleep.
Pediatric Cutoffs for OSA: In children 12 years of age and younger, an obstructive AHI greater than or equal to 1 is generally considered the diagnostic cutoff for OSA. In older adolescents, the adult cutoff of an AHI greater than or equal to 5 is typically utilized.
Evaluating Mild OSA: When the AHI falls between one and five obstructive events per hour, the clinician must assess additional PSG parameters—such as elevated CO2 (indicating obstructive hypoventilation), oxygen desaturation, and respiratory-related arousals—alongside clinical symptoms to determine further management.
Narcolepsy Criteria: PSG findings that support a diagnosis of narcolepsy include a rapid eye movement (REM) sleep latency of less than or equal to 15 minutes, or an MSLT showing a mean sleep latency of less than or equal to 8 minutes accompanied by two or more sleep-onset REM periods.
Idiopathic Hypersomnia Criteria: Diagnosis requires a PSG followed by an MSLT showing a mean sleep latency of less than 8 minutes with fewer than two sleep-onset REM periods. If the MSLT mean sleep latency exceeds 8 minutes, a 24-hour PSG demonstrating a total sleep time of at least 660 minutes is required.

In clinical situations where formal, in-lab polysomnography is unavailable, alternative diagnostic tests may be ordered to assess for sleep-disordered breathing.
These acceptable alternative modalities include nocturnal video recording, nocturnal oximetry, daytime nap polysomnography, or ambulatory (at-home) polysomnography.