Fig. 1.—
Compressed polysomnographic tracing from a patient with sleep apnoea/hypopnoea syndrome. a) and b) show 2 channels of electroencephalogram (EEG). c) and d) show genioglossus electromyogram (EMGgg1) and sternocleidomastoid electromyogram (EMGgg2), respectively. e) and f) show flow (pneumotachograph) and pressure at the nasal mask respectively. Application of forced oscillation during obstructive apnoeas; the oscillation at a frequency of 5 Hz can be seen in the pressure signal in the first of two consecutive apnoeas. Forced oscillation technique (FOT) did not result in an increase in EMGgg activity or affect the length of obstructive events. The horizontal bar in f) indicates application of FOT during 8 s.