Improving the detection of evoked responses to periodic stimulation by using multiple coherence—application to EEG during photic stimulation

Frequency-Domain Objective Response Detection Techniques Applied to Evoked Potentials: A Review

“…In order to overcome this drawback and improve the detection rates, Miranda de Sá and Felix (2002) suggested the employment of multivariate extensions of the ORD techniques, named MORD (Multivariate ORD), which use information of more than one EEG derivation. In this study, they introduced the Multiple Coherence (MC), a multivariate version of the MSC, and verified that the detection percentages can be improved by augmenting the number of EEG channels used.…”

“…The use of more than one derivation, as suggested by Miranda de Sá and Felix (2002), can improve the detection rates without the need of augmenting the exam duration (the number of EEG epochs used for ORD estimation). Figure 9 shows the MSC (M = 100 epochs) for [C3] and [C4], and the MC (M = 100 epochs) using both leads of volunteer #17.…”

“…Methods to accelerate the detection such as the application of a decreasing exponential (Tierra-Criollo et al, 1998) to the ORD techniques have been proposed. More recently, the employment of more than one EEG derivation in a multivariate ORD approach has been suggested in order to improve the detection probability (Miranda de Sá and Felix, 2002). These techniques constitute the state of the art for objectively identify sensorial responses to a stimulation.…”

Meta-Analysis of Genomic Data: Between Strengths, Weaknesses and New Perspective

“…Since these evoked responses exhibit very small amplitude in comparison with that of the spontaneous EEG, averaging techniques are often necessary to reveal them. One of such is the coherent average of the EEG triggered by the stimulation signal, which leads to an estimate of the cortical response and is called the evoked potential (EP) [14].…”

Post-processing of auditory steady-state responses to correct spectral leakage

“…In other words, a borderline but significant response could be mistakenly lost and, consequently, implicating in a medium impairment being confounded with a severe hearing loss. Additionally, the leakage of spectral information from the modulation band could increase the exam's duration since the probability of detecting a response would require more data segments (Miranda de Sá and Felix, 2002) in order to overcome the leakage effect; or a higher number of recorded channels (Felix et al, 2007). The fact of using windowed data to estimate the ORD is not at all disadvantageous; the time-windowed epochs help dealing with eventual non-stationary events in the data as well as increases the SNR by performing averaging.…”