What is the role of polysomnography (PSG) in diagnosing and managing sleep disorders?

Role of Polysomnography in Diagnosing and Managing Sleep Disorders

Polysomnography (PSG) is the gold standard diagnostic tool for evaluating sleep disorders, particularly sleep-disordered breathing, and should be utilized when specific clinical indications are present to guide appropriate treatment decisions and improve patient outcomes. 1, 2

Primary Indications for Polysomnography

Sleep-Disordered Breathing

• PSG is routinely indicated for the diagnosis of sleep-related breathing disorders including:

  • Obstructive sleep apnea (OSA)
  • Central sleep apnea (CSA)
  • Sleep-related hypoventilation disorders 3, 2

• PSG is specifically recommended when:

  • Evaluating patients with suspected sleep-disordered breathing
  • Titrating continuous positive airway pressure (CPAP) in patients with sleep-related breathing disorders
  • Documenting OSA prior to surgical interventions such as uvulopalatopharyngoplasty 3

Special Populations Requiring PSG

• Children with sleep-disordered breathing should be referred for PSG before tonsillectomy if they have:

  • Obesity
  • Down syndrome
  • Craniofacial abnormalities
  • Neuromuscular disorders
  • Sickle cell disease
  • Mucopolysaccharidoses 4

• PSG should be performed in infants with Prader-Willi syndrome at the time of diagnosis to rule out central apnea 4

Narcolepsy and Hypersomnia

• PSG followed by Multiple Sleep Latency Test (MSLT) is required for:

  • Evaluation of suspected narcolepsy
  • Assessment of excessive daytime sleepiness when other causes have been ruled out 5, 3

• Diagnostic criteria for narcolepsy include:

  • Mean sleep latency <8 minutes AND
  • ≥2 sleep-onset REM periods during MSLT 5

Other Key Indications

• PSG is indicated for:
  • Evaluating violent or potentially injurious sleep-related behaviors
  • Diagnosing REM sleep behavior disorder (RBD), which may predict neurodegenerative disorders
  • Assessing periodic limb movement disorder when clinically suspected
  • Evaluating parasomnias that don't respond to conventional therapy
  • Diagnosing sleep-related epilepsy 3, 1

Comprehensive vs. Limited Testing

Laboratory-Based PSG

• Laboratory-based PSG should be used when available for children requiring sleep assessment prior to tonsillectomy 4
• Full PSG includes:
  • Sleep staging (EEG, EOG, EMG)
  • Respiratory parameters
  • Cardiac monitoring
  • Body position
  • Limb movement 1, 2

Home Sleep Apnea Testing (HSAT)

• HSAT may be used as an alternative to PSG for diagnosing OSA in adults with:

  • High pretest probability of moderate to severe OSA
  • No significant comorbidities
  • No other suspected sleep disorders 4

• HSAT should NOT be used in patients with:

  • Comorbid medical conditions
  • Suspected alternative sleep disorders
  • For general screening purposes 4

Scoring and Interpretation Considerations

Arousal-Based Scoring

• PSG for OSA should include arousal-based scoring to:

  • Accurately capture all respiratory events
  • Prevent misclassification of OSA severity
  • Avoid misdiagnosis of other sleep disorders
  • Properly identify patients who need treatment 4

• Evidence shows that arousals, rather than hypoxemia alone, better predict hypersomnia in patients with OSA 4

Post-Diagnostic Management

Post-Surgical Monitoring

• Children with documented OSA on PSG should be admitted for inpatient, overnight monitoring after tonsillectomy if they:
  • Are younger than age 3
  • Have severe OSA (apnea-hypopnea index ≥10 events/hour)
  • Have oxygen saturation nadir less than 80% 4

Communication with Care Team

• PSG results should be communicated to the anesthesiologist prior to induction of anesthesia for tonsillectomy in children with sleep-disordered breathing 4

Common Pitfalls and Caveats

1. Relying solely on clinical assessment: Clinical diagnosis of SDB is a poor predictor of disease severity, making objective PSG assessment crucial 4

2. Neglecting arousal-based scoring: Not including arousal-based respiratory events may lead to underdiagnosis of OSA, misclassification of severity, or misidentification of other sleep disorders 4

3. Inappropriate use of home testing: HSAT should only be used in high-risk populations for moderate to severe OSA, not in patients with comorbidities or other suspected sleep disorders 4

4. Failure to perform PSG in high-risk children: Children with complex medical conditions should undergo PSG before tonsillectomy to identify those at highest risk for perioperative complications 4

5. Overlooking PSG's role in comprehensive evaluation: PSG should be one tool in the complete evaluation of sleep disorders patients, not used in isolation 4