Fig. 6

Illustration of the active laryngeal states for both obstructive apnea due to laryngospasm and the seizure-associated periods of central apnea. Each panel shows a segment of EEG, multi-unit recurrent laryngeal nerve activity (RLN), and ECG. The RLN, which carries motor output for both laryngeal abductors and adductors, is active during both types of apnea. Note the significant slowing and ST changes associated with obstructive apnea, but no ECG changes associated with central apnea. Shown to the right are three ECG sweeps for each type of apnea to illustrate the pronounced ST segment elevation and slowing during obstructive apnea and the uniform PQRST complexes during central apnea. The asterisks above the ECG recording mark the times of the high-resolution sweeps shown to the right (also marked with asterisks). The recording illustrating obstructive apnea is taken from the end of a seizure; seizure activity is present from the beginning of the illustrated data and an estimate of seizure offset (based on a complete flatlining of EEG) is marked by an arrow. Calibrations on the figure.