What Are the Indications for a Sleep Study?

Patient Presentation
A 2-month-old male came to clinic for his health maintenance examination. The mother is concerned about some episodes where he turns red in the face and shakes. There is no body stiffening or eye changes. The episodes last only a few seconds. The mother blows in his face and he gasps or make another sound terminating the episodes.
They are not associated with feeding and occur at different times of the day without warning. They have occured at least 10 times in the past two weeks. His mother reports that he is otherwise well.
The past medical history shows the infant was born full-term, and was appropriate for gestational age with no prenatal or perinatal complications. He went home with his mother at 48 hours of life and has been gaining appropriate weight.
The family history reveals an older sibling who died as an infant because of possible sepsis.
The review of systems is negative.
The pertinent physical exam shows a weight of 4.72 kg (25%), head circumference of 38 cm (25%), length 50 cm (50%), heart rate = 140, respirations = 36, and blood pressure = 90/55. He was alert and in no distress. His anterior fontanelle is open, soft and flat. Eyes show a red reflex bilaterally. His heart has a regular rate and rhythm without murmur. Lungs are clear with no flaring retracting or grunting. Neurological examination shows normal tone and strength. His cranial nerves III-IV are intact. He has normal deep tendon reflexes, Moro reflex, palmar grasp and blink reflexes are present.
Dermatological examination is normal. The rest of the physical examination was normal.
The work-up included a consultation with neonatology who recommended monitoring the child in the hospital to observe these episodes. No episodes occurred after 30 hours of monitoring and the infant was discharged to home on an apnea monitor until a sleep study could be performed.
The sleep study revealed a diagnosis of obstructive sleep apnea which is being further evaluated at this time.

Sleep studies or Polysomography (PSG) continously record multiple physical parameters of sleep and respiration. Sleep is monitored by electroencephalogram, electrooculogram and electromyogram.
Respiration is monitored by nasal and oral airflow, respiratory effort (by movement electrodes on the body), oxygen satuation and carbon dioxide.
An electrocardiogram is also often used along with monitors for body position and snoring volume and the patient may be monitored by a video camera.
There is little night to night variability in pediatric patients so one night is usually sufficient for diagnosis. Almost any age patient can be accomodated.

The PSG evaluates sleep architecture (REM and non-REM sleep) and sleep quality and disturbances can be identified.
Central or obstructive respiratory events are also identified. Central apnea is the absense of oranosal airflow with no respiratory effort. Central apnea is found in all normal children but last less than 20 seconds.
Obstructive apnea is cessation of oronasal airflow with continued respirtory effort. These are rare in children. Hypopnea is a 50% of more decrease in the amplitude of the oronasal airflow with respiratory effort. Hypopneas are common in children.
Apneic events can also be mixed and are common in younger children.

Learning Point
Indications for sleep studies include:

  • Obstructive sleep apnea (OSA) – To diagnose OSA is the most common reason for PSG. OSA is recurrent events of partial or complete upper airway obstruction during sleep which disrupts normal ventilation and sleep patterns.
    Untreated OSA can cause growth failure, pulmonary hypertension and cor pulmonale, and learning and behavior problems including problems with attention and memory.
    Primary snoring is children who snore but have no sleep or respiratory abnormalities. History and physical examination are poor at discriminating between primary snoring and OSA. Screening pulse oximetry is predictive of OSA if it is positive (positive predictive value of 97%) but is not good if it is negative (negative predictive value of 47%).
    As PSG is often only available in larger medical centers, oximetry can be a useful screening test. While not excluding OSA, a negative test may reassure the family and pediatrician that the child is unlikely to have severe OSA while waiting a full PSG.
    Children at risk for OSA include upper airway abnormalities (e.g Pierre-Robin Sequence), genetic/metabolic problems (e.g. Down Syndrome), neurological syndromes (e.g. cerebral palsy, Prader-Willi syndrome) and obesity. OSA can be treated with nocturnal ventilation or surgery.

  • Neuromuscular disease – With the combination of respiratory muscle weakness, impaired central ventilatory control and decreased upper airway tone, children with neuromuscular disease are at risk for central and obstructive sleep apnea.
    Symptoms of nocturnal respiratory failure include: daytime sleepiness or behavioral changes, morning headache, fatigue, difficulty sleeping, and needing frequent repositioning in the night. Treatment is nocturnal ventilation.

  • Central hypoventilation – is defined as normal ventilation while awake and hypoventilation while asleep. It is due to inadequate central respiratory control and can be congenital or acquired. Treatment is nocturnal ventilation.
  • Monitoring nocturnal ventilation needs – Children requiring nocturnal ventilation need annual reassessment because of growth or possible disease progression.
  • Excessive daytime sleepiness and narcolepsy – Excessive daytime sleepiness can be caused by sleep disruption, insufficient sleep, brain lesions, depression and drugs. Narcolepsy is a problem of REM sleep regulation with excessive daytime sleepiness as its primary symptoms. Narcolepsy also has sudden muscular weakness (i.e. cataplexy) as a major symptom.
  • Parasomnias are disruptive sleep behaviors that occur in healthy children and generally disappear by adolescence. Common parasomnias include sleep walking, night terrors and confusional arousal. These are due to impaired arousal from deep sleep.
  • Otherwise unexplained episodic disorders.

Questions for Further Discussion
1. What is the normal sleep pattern for infants?
2. What is the differential diagnosis of episodic disorders in infants?

Related Cases

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effecively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused case is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.

  • Interpersonal and Communication Skills
    18. Using effective nonverbal, explanatory, questioning, and writing skills, the healthcare professional uses effective listening skills and elicits and provides information.

  • Systems Based Practice
    23. Differing types of medical practice and delivery systems including methods of controlling health care costs and allocating resources are known.

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Information prescriptions for patients can be found at Pediatric Common Questions, Quick Answers for this topic: Childhood Sleep Apnea.

    To view current news articles on this topic check Google News.

    Davey MJ. Investigation of Sleep Disorders. J. Paediatr. Child Health. 2005:41:16-20.

    Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:333-34, 417-420.

    Donna M. D’Alessandro, MD
    Associate Professor of Pediatrics, Children’s Hospital of Iowa

    November 21, 2005