Discriminating somatic evoked potentials using a pairwise procedure

Generally, investigators use only the magnitude spectra of a signal for processing or for discriminant analysis, with the phase information discarded. However, it is not difficult to generate two different time domain signals having identical magnitude spectra in the frequency domain. Thus the phase information should not be neglected. This paper presents the results of a simulation study of a discriminant analysis procedure for paired variables, e.g. magnitude and phase pairs. The procedure is then applied to discriminating somatic evoked potentials from normal and damaged spinal cords with excellent results.