Distortion of Waveform of Asynchronous Averaging for Evoked Potential with Varying Peak Latency and Its Recovery
Shigeto Nishida, Masatoshi Nakamura, Hiroshi Shibasaki · Transactions of the Society of Instrument and Control Engineers · 1999
If evoked potentials with varying peak latency are averaged time-locked to stimulus, the averaged waveform is deteriorated due to the asynchronous averaging to each peak of evoked potential. In this study, deterioration characteristics of the waveform of asynchronous averaging were theoretically analyzed based on an assumption that a peak latency of the evoked potential varied according to a Gaussian distribution. By using the derived equation for the characteristics, a method for reconstructing the original waveform of evoked potential from the asynchronous averaged waveform was proposed. Furthermore, we derived a standard deviation of the estimation for the reconstructed waveform and obtained an interval estimate of the original waveform. After an evaluation for the proposed methods by using simulation data for evoked potential, we applied the method to actual data for event-related potential of P300 and obtained satisfactory results.