Pain Measurement by Signal Detection Theory

Abstract

Pain is a subjective experience with somatosensory, emotional, cognitive, and other components; yet, if we are to understand and treat pain, we must measure pain in a reliable and valid manner. To clarify these problems, various psychophysical models have been used to examine verbal reports to calibrated electrical, thermal, pressure, and other physical stimuli. These psychophysical procedures include the traditional threshold, Stevens magnitude estimation, various multidimensional scaling procedures, as well as signal detection, or more descriptively, sensory decision theory (SDT). The merit of the SDT approach resides in its unique ability to quantify separately sensory and attitudinal parameters. The index of discriminabil-ity, d’ or P(A), measures the accuracy (it is possible in the binary decision procedure to score the subject’s response as right or wrong) with which an individual distinguishes among stimuli of various intensities. This index of sensory performance has been demonstrated to be essentially uninfluenced by changes in the subjects’ expectation, mood, motivation, and other attitudinal variables.