Event-related potentials (ERPs) are widely used in brain-computer interface applications and in neuroscience.\nNormal EEG activity is rich in background noise, and therefore, in order to detect ERPs, it is usually necessary to take\nthe average from multiple trials to reduce the effects of this noise. The noise produced by EEG activity itself is not\ncorrelated with the ERP waveform and so, by calculating the average, the noise is decreased by a factor inversely\nproportional to the square root of N, where N is the number of averaged epochs. This is the easiest strategy\ncurrently used to detect ERPs, which is based on calculating the average of all ERPââ?¬â?¢s waveform, these waveforms\nbeing time- and phase-locked. In this paper, a new method called GW6 is proposed, which calculates the ERP\nusing a mathematical method based only on Pearsonââ?¬â?¢s correlation. The result is a graph with the same time\nresolution as the classical ERP and which shows only positive peaks representing the increaseââ?¬â?in consonance with\nthe stimuliââ?¬â?in EEG signal correlation over all channels. This new method is also useful for selectively identifying\nand highlighting some hidden components of the ERP response that are not phase-locked, and that are usually\nhidden in the standard and simple method based on the averaging of all the epochs. These hidden components\nseem to be caused by variations (between each successive stimulus) of the ERPââ?¬â?¢s inherent phase latency period\n(jitter), although the same stimulus across all EEG channels produces a reasonably constant phase. For this reason,\nthis new method could be very helpful to investigate these hidden components of the ERP response and to\ndevelop applications for scientific and medical purposes. Moreover, this new method is more resistant to EEG\nartifacts than the standard calculations of the average and could be very useful in research and neurology. The\nmethod we are proposing can be directly used in the form of a process written in the well-known Matlab\nprogramming language and can be easily and quickly written in any other software language.
Loading....