Reliability of scoring arousals in normal children and children with obstructive sleep apnea syndrome

STUDY OBJECTIVES: Scoring of arousals in children is based on an extension of adult criteria, as defined by the American Sleep Disorders Association (ASDA). By this, a minimum duration of 3 seconds is required. A few recent studies utilized modified criteria for the study of children, with durations as short as 1 second. However, the validity and reliability of scoring these shorter arousals have never been verified. Based on studies in adults, we hypothesized that interscorer agreement for scoring arousals shorter than 3 seconds was poor. DESIGN: Retrospective review of polysomnograms by 2 experienced sleep practitioners who independently scored arousals according to the ASDA 3-second criteria and modified duration criteria of 1 and 2 seconds. SETTING: Academic hospital. PATIENTS OR PARTICIPANTS: 20 polysomnographic studies from children aged 3 to 8 years with mild to severe obstructive sleep apnea syndrome, and 16 polysomnographic studies from normal children. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The intraclass correlation coefficient for scoring ASDA arousals was 0.90 (95% confidence interval: 0.81-0.95), indicating excellent interscorer agreement. The intraclass correlation coefficient for scoring modified 1-second and 2-second arousals were 0.35 (95% confidence interval: 0.02-0.61) and 0.42 (95% confidence interval: 0.12-0.65) respectively, indicating poor to fair interscorer agreement. Furthermore, modified 1-second and 2-second arousals accounted for less than 15% of all arousals scored. CONCLUSIONS: We conclude that there is much poorer interscorer agreement for scoring arousals shorter than 3 seconds, when compared to the standard ASDA criteria. We propose that scoring of arousals in children should follow the standard ASDA criteria.