There are many demands on a good pain-scale. It should be possible to: use for all kinds of pain; determine direct levels of intensity over the total range; treat responses with statistical methods, preferably parametric statistics; study degrees of changes with stimulus intensity, medication and time; make interindividual, intermodal and psychophysiological comparisons; avoid ceiling and floor effects; make estimations and also productions; determine psychophysical S-R-functions, possible to describe with a general equations as, e.g., R=a+c(S-b)^n, where a is the basic “noise” at rest (or the absolute threshold), and b is the starting point of the function; make two-way communication; handle round off tendencies; use internationally. To meet these demands the scale must be constructed according to basic psychophysical and linguistic knowledge, and tested in relevant experiments. To cover the total subjective range there is a need of a number variation from 0 to 50 or a little more, about 26. Several anchors should be used that people understand very well, and that are placed correctly. Most existing scales do not fulfill these demands. A common drawback is that there is a too limited range, or a maximal endpoint defined as “Highest (or Worst) Imaginable”, which is not a schematized conception and problematic for interindividual comparisons. Examples are the Visual Analogue Scale (VAS), and is the "Labeled Magnitude Scale" (LMS) for oral sensation. On the LMS verbal anchors are placed to give ratio data, but “Strong” is 34.7, “Very strong” 52,5. For general usage, e.g., in two-way communication for prescription of exercise, this is not good, nor does the scales facilitate predictions of max-levels from sub-max estimations. The best scales are the Borg CR Scales® (CR10 and CR100). In these scales quantitative semantics is used by applying ratio scaling to determine interpretation, meaning position in the range for congruence between anchors (labels) and numbers, and preciseness meaning interindividual agreement. It is especially important that the anchors for Zero and Maximal refer to schematized conceptions. A maximal magnitude is defined as a maximal perceived exertion and effort, for example a maximal heaviness. These ideas have been presented during several ISP meetings by G. Borg, last time in Freiburg 2013. The CR10 has been used in many studies, e.g., during tests of functional capacity and chest pain, and muscular-skeletal pain. The CR100 scale has, however, a greater potential as a general scale making possible determinations of most kinds of perceptual magnitudes. An advantage to the CR10 is that decimals need not be used and that the dynamic range is bigger and more in accordance with the psychophysical demands. The extra constants in the power function can then better reflect the true sensory processes.
Lund: International Society for Psychophysics , 2014. 10-10 p.