Figure 1.

Raw data from three normal children during stage 4 sleep demonstrating the range of genioglossus EMG (EMGgg) responsiveness during six negative-pressure challenges. Each tracing is approximately 4 min. (A) No increase in the EMGgg or flow is evident during the negative-pressure challenges. (B) Some increase in the EMGgg is noted during challenges 2–6. An increase in inspiratory flow is evident on breaths 4–5 during challenges 2–4. (C) A brisk EMGgg response accompanies challenges 2–6 and is associated with flow at or above baseline without arousal.