Pain intensity is the most frequently evaluated dimension of pain. In situations where there is acute, short-term pain of an obvious cause (e.g. dental extraction), it may be sufficient to monitor only pain intensity and forego tracking other aspects of the multidimensional pain experience2.
There are several types of assessment tools used to evaluate pain intensity (See Figure 3)2:
- Visual analog scale
- Numeric rating scale
- Adjective rating scale
- Faces pain scale
(i) Visual analog scale
The visual analog scale is presented graphically with a 10-cm baseline and endpoint descriptors. Patients place a mark on the line at a point that best represents their pain. Their responses are scored by measuring the distance of the mark from the left-hand end of the scale (“anchor”)2.
(ii) Numeric rating scale
This scale may be presented graphically or verbally, with 0 representing “no pain” and 10 representing “the worst possible pain”. Patients volunteer a number that best represents their pain intensity2.
(iii) Adjective rating scale
The adjective rating scale employs descriptors of pain intensity such as “none”, “mild”, “moderate” or “severe”2.
(iv) Faces pain scale
This scale is a pictorial representation of faces experiencing a range of pain intensities from “no pain” up to “worst pain possible”. Patients choose the picture that best represents their pain intensity. This scale is often employed in young children, elderly patients or in persons who experience difficulty in communicating6.