Sleep architecture and the apnoea-hypopnoea index in children with obstructive-sleep apnoea syndrome

This study aimed to examine the sleep architecture and craniofacial morphology in a group of children divided by different levels of apnoea-hypopnoea index (AHI), 5, 4.5, 4, 3.5, 3 and 2.5, and to determine an AHI threshold value at which sleep architecture is most affected. 23 children, who were selected from a preliminary questionnaire survey about sleep-related breathing disorders, were evaluated with cephalometric radiographs and overnight polysomnography. The findings indicated that the children with AH1 >= 2.5 and >= 3 showed significantly larger numbers of waking (p < 0.005) and desaturation index (p < 0.01) than those with AHI < 2.3 and < 3, respectively. Significantly (p < 0.05) higher amounts of waking and lower amounts of REM as a percentage of total sleep time (TST) were also found in the children with AH1 >= 3. In the subgroups with AHI >= 3.5 and >= 4, only the percentage of REM was found to be significantly (p < 0.05) lower. No significant differences were found at the AHI threshold of 4.5 and 4. AHI correlated significantly (p < 0.05) with the number of awakenings, amount of waking as a percentage of TST, desaturation index and oxygen saturation nadir. Higher incidence of skeletal Class II pattern was found in children with AHI >= 2.5 and >= 3, and Class III in those with AHI < 2.3 and < 3, respectively. The effects on polysomnographic characteristics demonstrated to be the greatest on children at the AHI threshold of 3. In addition, the evaluation of oxygen saturation can be used to provide some information concerning the severity of sleep-related breathing disorders.