SPECTRAL ANALYSIS OF DIAPHRAGMATIC EMG'S DURING PERIODIC AND NORMAL BREATHING IN INFANTS.

The diaphragmatic electromyogram was recorded, using surface electrodes, for five infants during both periodic and normal breathing. Power density spectra, based on the FFT, were determined for the EMG during the buildup and decline portions of periodic breathing and during normal breathing. The spectra were found to be similar for all cases and were concentrated in the bandwidth 23-188 Hz. Electrode motion was evident at frequencies below 23 Hz. The effect of the cardiac artifact was reduced by using only sections of the EMG signal where the QRS complex was not present. By calculating the centroid frequency, it was shown that there is no shift of the EMG power during periodic breathing as compared to normal breathing.