Component loadings for a previously reported real-life example of a principal component analysis performed on the intercorrelation matrix among eight pain threshold measurements ([3]; for comparison, see Table 2 in that publication).

The relevant four principal components (PCs) are given in bold font. Without the present method, only PCs #1 - #3 with eigenvalues > 1 [11,12] could be validly retained. The set of three principal allowed to show that all different pain measures shared an important common source of variance (PC1) pain evoked by cold stimuli, with or without sensitization by topical menthol application, by blunt pressure or by electrical stimuli (5 Hz sine waves) shared a common source of variance (PC2), and a further common source of variance e was shared by pain evoked by heat stimuli, with or without sensitization by topical capsaicin application, or by punctate mechanical pressure. However, with applying the here reported method, PC4 can now be also be retained, which singles out heat pain corresponding to the different pathophysiology underlying heat perception.Component loadings for a previously reported real-life example of a principal component analysis performed on the intercorrelation matrix among eight pain threshold measurements ([3]; for comparison, see Table 2 in that publication).