<p>Four channel multi-variate training is a type of neurofeedback that Rob Coben invented, which measures and trains coherence between four electrodes. The protocol works when inputs from sensors are transformed into multivariate coherence values across all possible combinations of the four locations or sensors. This information makes up the reward band. Additionally, there are three user-defined inhibit hands that encourage a decrease in EEG frequencies, as a form of amplitude training.&nbsp;&nbsp;</p><p>The multivariate nature of how coherence is calculated comes close to the brain’s noise, itself, and Coben theorizes this makes it easier for the client to train, as opposed to the typical coherence model, where cross correlations between pairs of electrodes is used (bivariate coherence). The compromise to using pairwise coherence measures include inter-electrode distance, volume conduction of the brain, and the inability to capture three-dimensional brain activity (Nnez, 1994; Nunes and Srivinasan, 2006).</p><p>This method has been demonstrated on the EEGer Training system (developed by Ed Hamlin). Coben and Myers (2010) have shown that four channel multi-variate training has had greater efficacy than single or dual channel coherence training; they believe that one advantage to four-channel multi variate training is the number of electrodes used, as well as the statistical sophistication of what is actually fed back to the client.</p><p>Coben intends to continue to refine his model of four channel multi-variate coherence training, foreshadowing future enhancements involving functional connectivity.&nbsp;</p>