Sleep Instabilities Assessed by Cardiopulmonary Coupling Analysis Increase During Childhood and Adolescence

Figures

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  FIGURE 1. Variations of cardiopulmonary coupling (CPC) parameters during childhood and adolescence. (A) Estimated total sleep time (ETST), (B) Very low frequency coupling (VLFC) indicating REM/wake states, (C) Low frequency coupling (LFC) indicating unstable non-REM sleep, i.e., cyclic alternating pattern (CAP) sleep, (D) High frequency coupling (HFC) indicating stable non-REM sleep, i.e., non-CAP sleep, (E) Elevated low frequency coupling (e-LFC) indicating disordered breathing, and (F) fragmentation of sleep. The solid lines show the moving average (21 consecutive data points) and the dashed line indicates the linear regression model.

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  FIGURE 2. Comparison of different age groups with respect to the cardiopulmonary coupling (CPC) parameters. (A) Estimated total sleep time (ETST), (B) Very low frequency coupling (VLFC) indicating REM/wake states, (C) Low Frequency Coupling (LFC) indicating unstable non-REM sleep, i.e., cyclic alternating pattern (CAP) sleep, (D) High Frequency Coupling (HFC) indicating stable non-REM sleep, i.e., non-CAP sleep, (E) Elevated low frequency coupling (e-LFC) indicating disordered breathing and (F) fragmentation of sleep. Each age group shows three values: the average of the entire group is plotted in the middle (black points), open squares on the left of each black point show the average of male subjects and open triangles show the average of female subjects. The small letters in each diagram refer to significant differences (p < 0.05) with respect to the following age group: a: <7 years, b: 7–9 years, c: 10–13 years. Black letters refer to the whole group, gray letters on the left and right of the black letter denote males and females, respectively.