Pain is one kind of complex and truly intractable experience that makes the measurement a challenge for modern-day scholars. Try stubbing your foot against a stone or biting your tongue and you will see how the pain experienced varies widely.
This article is a review of the different ways of measuring pain.
Unidimensional Scales for Measuring Pain
In a conventional clinical setting, pain measures are expected to be simple, easy to administer, and easily understood. This makes unidimensional scales of pain ideal for this purpose. A unidimensional scale often involves a numerical rating scale (usually from 1 to 10). It is designed such that even with minimal effort, it can be administered multiple times.
The far left of the scale usually represents ‘no pain’ and the far right stands for the worst imaginable kind of pain. The numerical rating scale (NRS) can be administered verbally and there’s no need to request for the mobility of the patient before the test can be administered.
Instead of the numerical rating scale, a visual analog scale can also be used whereby a patient mark anywhere along a 10-cm line to indicate how severe the pain experienced is. A verbal rating scale is another widely employed scale and is often used by patients who have difficulty expressing the level of pain experienced on a numerical scale. The descriptors allowed include ‘no pain’, ‘mild pain’, ‘moderate pain’, and ‘severe pain’.
Multidimensional Scales for the Measurement of Pain
In several situations involving pain, a simple instrument measuring just one pain point is in no way effective. There are diverse forms of pain and they can take on a plethora of forms at the same time. For instance, think of the pain felt when a patient loses a loved one to an avoidable cause; it’s a mixture of sorrow, guilt, regret, etc.
This makes it important to have tools that measure several dimensions of pain with a combination of several other things being the intensity of the pain, the quality of the pain, the effect, the interference with general functions, etc.
Being able to assess the pain experience in a more complex way makes up for the erstwhile lack of association between the intensity of the pain and the way in which it causes the individuals to appear disabled.
Best Pain Inventory-Short Form
As the name implies, the form captures two domains of pain; the first is the sensory intensity of the pain. The second domain covered is the degree to which the pain interferes with the different areas of life. This test also comprises a 17-item scale that aims to record and measure the location of the pain, the use of pain medication, and the response to different treatments.
The Short-Form McGill Pain Questionnaire
We also have the short-form pain questionnaire (SF-MCQ) and this is a well-validated measure of pain that has been used extensively in research. Here, the patients are expected to rate their pain in terms of their sensory output. This could be sharp or stabbing. They also rate the pain they feel based on their affective terms; could be frightening or sickening.
In this test, there are over 15 total descriptors available and each of the items is rated on a 4-point scale, the least being “none’ and the most being ‘severe’. The SF-MPQ also has a single visual analog scale for rating the intensity of the pain and another verbal rating scale that covers the general pain experience.
West Haven-Yale Multidimensional Pain Inventory
There’s a West-Haven-Yale Multidimensional Pain Inventory (WHYMPI) that serves as a comprehensive pain outcome measure containing 12 subscales and 52 items. The subscales include a perceived interference of pain in several areas, the response patients get from a significant other, the severity of the pain, the level of participation in various work, and even a perceived for of life control.
In this meter, the items are assessed on a 7-point scale and the scale yields the useful classification of the patients, giving us categories such as a dysfunctional patient, adaptive coper, or interpersonally depressed patient.
This form of measurement is commonly used in patients that are noncommunicative and for whom a direct measure of the pain experienced is not feasible. In this situation, there are tools that are used to measure the facial or bodily movements and then this serves as a proxy for the pain. A perfect example of a patient who is observed via this method is an infant. Even though the scales are clinically necessary in several cases, they are not usually accepted as outcomes for clinical trial reporting.
As earlier stated, pain is a seemingly relative term that varies from patient to patient. It can prove daunting at first, but it is in no way impossible to do. The aforementioned metrics are sufficient to carry out the job when measuring pain.