Arousals and obstructive sleep apnea syndrome in children

Observations of children with obstructive sleep apnea syndrome (OSAS) show a restless sleep. But there is no significant disturbance of sleep macrostructure as in adult OSAS patients. It will be proved, whether the analysis of arousals permits a comprehensive characterization of this respiratory related sleep disturbance. Considering the problems in EEG-arousals detection in dependence of age and maturation we will compare the results of analysis of EEG- and movement arousals to find out a more practicable way for arousal analysis in childhood.

Twenty OSAS pediatric patients (aged 3.1-14.3 years, median 7.5 years) and 20 age matched children with no OSAS (aged 3.3-13.9 years, median 7.9 years) were examined polysomnographically. Clinically confirmed OSAS patients with an apnea/hypopnea index (AHI) > or = 5/h TST (total sleep time) were examined during 1 whole night before treatment (diagnostic night - baseline) and after/under receiving therapy. Various polygraphic parameters to describe the macrostructure of sleep (sleep efficiency, NREM 1-4, REM) and the microstructure of sleep (EEG- and movement arousals) were analyzed. Furthermore the AHI, heart rate and oxygen saturation were evaluated.

Patients with clinically and polysomnographically confirmed OSAS had significantly more EEG (median 21.0/interquartile range 9.31 /h TST) and movement arousals (20.4/13.1 /h TST) before therapy than after/under therapy (EEG: 9.9/6.3 /h TST; movement: 9.2/3.8/h TST). The frequency of arousals was comparable in OSAS children after/under treatment and controls (EEG: 9.0/4.2/h TST; movement 9.3/3.4/h TST). In the 3 groups there was no significant correlation between AHI and number of EEG-arousals and movement arousals. AHI was significantly higher in OSAS children in comparison to controls and treated OSAS. In contrast to adults, sleep efficiency and macrostructure of sleep were not different in controls and OSAS children with or without treatment. Also, oxygen saturation and heart rate, had the same values in controls, OSAS children and OSAS children after/under treatment.

OSAS in children is characterized by a restless sleep, i.e. by an enhanced number of movement and EEG-arousals. The microstructure of sleep but not the macrostructure is changed. There is a high coincidence between EEG arousals and movement arousals. The evaluation of arousals especially the analysis of movement arousals is helpful to estimate treatment effect in OSAS patients.