[Identification of the actual experiencing of pain. Methodological basis for an evaluation].
FUNDAMENTALS: The doctors don't have reliable instruments in order to detect the painful experience in a patient with intention of deceiving. The objective of this investigation is the development of an instrument that helps the doctors on that task. METHOD: The investigation is based on that the pain is not possible to evoke. A patient that doesn't feel pain, really, will introduce the modifications characteristic of all memory when requests you that he/she describe the pain that says feel. The will of deceit will also distort their description. A discriminant analysis will detect the difference between the description of a pain that is not present and another that yes it are, and between the sincere descriptions of the deceiving one. RESULTS: The descriptions of the pain carried out by two different samples of nursing students have been studied with a list of pair of antonym adjectives (Osgood's semantic differential). A subgroup of the first sample described a pain that they suffered in the same moment of description, and the other subgroup described a suffering pain some days before. In the other sample, a subgroup made a sincere description of their pain and other subgroup described the pain with will of deceiving the interviewer. The investigation has provided two discriminant models. A discriminant model differentiates between a present and another remembered pain (sensibility: 0.75; specificity: 0.85; kappa reliability: 0.60; p < 0.000000001; probability of success p: 89%). The other discriminant model differentiates between a description of a pain with will of deceiving and another pain described sincerely (sensibility: 0.94; specificity: 0.95; kappa reliability: 0.89; p < 0.000000001; probability of success p: 97%). CONCLUSIONS: The results of this investigation seem to demonstrate that it is possible to discriminate between the descriptions of real pains and the suspicious pains of not being real, and that also one is able to discriminate between pains described with will of deceit and pains described sincerely. These discriminant models allows to classify the description of the subjects in four groups: "liars", "sincere", "magnifiers", and "psychogenic". However, it is necessary still carry out more effort of investigation so that these results could be replied in patients that suffer pain.