Article Text

Download PDFPDF
First night effect for polysomnographic data in children and adolescents with suspected sleep disordered breathing
  1. S L Verhulst1,
  2. N Schrauwen1,
  3. W A De Backer2,
  4. K N Desager1
  1. 1Department of Pediatrics, University Hospital of Antwerp, Belgium
  2. 2Department of Respiratory Medicine, University Hospital of Antwerp, Belgium
  1. Correspondence to:
    Dr S Verhulst
    University of Antwerp, Department of Pediatrics, Campus Drie Eiken, Office T4.27, Universiteitsplein 1, 2610 Wilrijk, Belgium; stijn.verhulst{at}


Aims: To assess the presence of a first night effect (FNE) in children and adolescents and to examine if a single night polysomnography (PSG) is sufficient for diagnosing obstructive sleep apnoea syndrome (OSAS).

Methods: Prospective case study of 70 patients (group 1: 2–6 years, n = 22; group 2: 7–12 years, n = 32; group 3: 13–17 years, n = 16) referred for OSAS. Diagnostic criteria for OSAS: one or more of the following: (1) obstructive apnoea index (OAI) ⩾1; (2) obstructive apnoea hypopnoea index (oAHI) ⩾2; (3) SaO2 ⩽89% in association with obstruction.

Results: In all age groups, but mainly in the oldest children, REMS increased during the second night, mainly at the expense of stage 2 sleep. The first night PSG correctly identified OSAS in 86%, 91%, and 100% of the children for groups 1, 2, and 3 respectively. This represents 9% false negatives for OSAS when only the first night PSG was used. All cases missed had mild OSAS, except for one with oAHI >5 on night 2. There were also seven patients with OSAS on night 1 but with a normal PSG on night 2: all had oAHI <5.

Conclusion: There is a FNE in children and adolescents. A single night PSG is sufficient for diagnosing OSAS, but in cases with a suggestive history and examination and with a negative first night, a second night study might be advisable.

  • AHI, apnoea hypopnoea index
  • FNE, first night effect
  • OAI, obstructive apnoea index
  • oAHI, obstructive apnoea hypopnoea index
  • OSAS, obstructive sleep apnoea syndrome
  • PS, primary snoring
  • PSG, polysomnography
  • REML, REM sleep latency
  • REMS, rapid eye movement sleep
  • SL, sleep latency
  • SaO2, oxygen saturation
  • SDB, sleep disordered breathing
  • SPT, sleep period time
  • TIB, time in bed
  • TST, total sleep time
  • first night effect
  • polysomnography
  • obstructive sleep apnoea
  • sleep disordered breathing

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Published Online First 13 December 2005

  • Competing interests: none

Linked Articles

  • Atoms
    Howard Bauchner