Figure 6. Example of obstructive hypopnea in non-REM sleep (stage N2).

The figure shows multiple facets of an obstructive hypopnea. However, please note that as hypopnea is evolving, early on thoracoabdominal excursions are in phase for 3 breaths but become out of phase as the event progresses. Also, thoracoabdominal excursions are in phase with recovery simultaneous with an arousal and a leg movement. ECG = electrocardiogram, EEG = electroencephalogram, EOG = electro-oculogram, Microphone = , Flow = , O₂ Sat = oxygen saturation, T_i = inspiratory time.