Semantic functional measurement of pain: integrating perception and language.

This study used Functional Measurement (FM) scaling procedures to demonstrate that subjects can scale and average the intensity or unpleasantness of pain sensations produced by an electrical tooth pulp stimulus and symbolized by a word. Unlike conventional psychophysical scaling methods, FM includes a testable validity criterion that must be met before the resultant scales are accepted. Twenty subjects used a handgrip dynamometer to rate all possible pairs of (1) 5 tooth pulp stimuli ranging in equal log steps from pain threshold to tolerance, and (2) 5 descriptors of sensory intensity or unpleasantness, twice each for a total of 50 stimulus pairs. The results show that subjects can average the pain magnitude produced by a tooth pulp stimulus with pain magnitude symbolized by a word and that this ability varies with the type of words used. FM produces separate scales of pain intensity, verbal magnitude and psychophysical ability. This method may provide a new and promising tool for the assessment of pain experience.