rdipi is the real dipole location of the simulated EEG data. r^dipi is the source location detected by the inverse calculation method. i and j are the indices of locations of estimated and the actual sources. N I and N J are the total numbers of estimated and undetected sources respectively. In current distributed-source reconstruction methods, a source location was defined as the location where the current strength was greater than a set threshold value. The first term in (14) calculates the mean of the distance from each estimated source to its closest real source. The corresponding real source is then marked as a detected source. All the undetected real sources made up the elements of data set J. The second term calculates the mean of the distance from each of the undetected sources to the closest estimated sources.
