MEASURING PAIN - page 2
The following is an editorial on the topic of Measuring Pain. It is provided complements of Jim Meadows from his regular newsletter on orthopedic physical therapy. It is from Newsletter #4 which can be found with the rest of his newsletters in the Newsletters section of Swodeam.com .
That the numeric pain scale is a tool that will allow the therapist to know the absolute level of the patients pain is also untrue. There are no methods yet known, and I include the dolorometer in that statement, that allow absolute levels of pain to be determined and it may be that to discuss pain in terms of absolutes is illogical anyway as pain is not a sensation but an experience. Pain is not exactly, and often is not even in the same ballpark, proportional to the noxious stimulus. The amount of pain the patient experiences for a given stimulus can vary wildly with time of day or month, mood, how ready the patient is for the pain, how much damage the patient believes is being done (that is how severe the pathology is believed to be), cultural background, etc.
That these scales more easily demonstrate changes in pain than the patients words may or may not be true. But it cannot, without an awful lot of explanation, tell the therapist how the pain has behaved over a given period such as a day or a weekend with anything like the economy and detail that the patient can provide with the use of words. If the scales drops say two levels between two treatment sessions does this imply that the patient has improved by 20%. It would do if the scale was linear but is it? How did the therapist describe this aspect of the scale (my impression is that this aspect is not explained, the assumption being that the patient would understand it to be linear). But is this assumption warranted. With higher levels of pain is a drop of two levels from say a 9 to a 7 more or less significant to the patient than a two level drop from say 4 to a 2.
As far as I know, there is no evidence that the patient or therapist or both understand the numeric scale better than words. And even if it were true, then it is probable that the patient would need more training in the scales than is usually given if conversion from words to numbers is to be accurately understood by both parties and to the other parties to whom that information is to be communicated. I once had a patient who was an engineer and made the scales logarithmic (bloody-minded no doubt but illuminating) so that his 3 was quite severe and changes in the pain were almost non-existent even though his pain levels dropped significantly and rapidly. We are humans and think in words and images not in numbers, unless you are a trained physicist or mathematician and probably not even then. To force the substitution of numbers for words cannot result in as accurate determination of an experience as when words are used.
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