Identifying respiratory-related evoked potentials

This study further demonstrates that the wavelet approach to the analysis and characterization of respiratory-related evoked potentials (RREPs) is a more efficient method than traditional ensemble averaging. Wavelet decomposition of the 200 trial ensemble averaged evoked responses results in smoothed signals at scale 4 with characteristics similar to those present in the ensemble averages, indicating that the wavelet approach permits accurate estimation of RREPs. Furthermore, subsequent reconstruction from the last 4 scales produces signals nearly identical to the original smoothed responses, demonstrating the validity of the reconstruction process. The wavelet approach is not only useful in the characterization of long term evoked responses, the wavelet estimates of short term (5-, 10-, and 25-trial) evoked responses also show high correspondence to the original signals and contain components similar among short term estimates. The similarities among short term estimates demonstrate that wavelet decomposition of successive short averages produces estimates of the signal that are stable. Although the responses of one subject showed significant and stable components in as few as 10 trials, variations in the level of background EEG activity among subjects may cause slight differences in the minimum number of trials required