Pain scale types: Benefits and limitations

Pain scales are instruments for individuals to describe the pain level they feel. To evaluate patients , healthcare professionals may also use pain scale charts.

There are several different scales for pain, each with its pros and cons.

This article discusses what a pain scale is, how it functions, and some of the various scales’ advantages and disadvantages.

What is a pain scale?

pain scale

A pain scale is a graph that indicates various pain levels, from moderate to severe. Pain scales can be used by people to help them describe how much pain they experience.

There are several pain scales, but one of the four main kinds is mostly used by healthcare practitioners and researchers:

  • The numerical scale: Measures pain on a scale of 1–10.
  • The visual analog scale: Categorizes pain along a horizontal line, ranging from mild to severe.
  • Faces pain scale – revised (FPS–R): Uses a horizontal line, illustrated by facial expressions to represent different pain levels.
  • The verbal rating scale: A person describes their level of pain in words.

These pain scales are unidimensional, meaning that to explain their pain, people may use only words or pictures. Multidimensional scales of pain tend to be more complex and to take longer to use.

It is important to remember that an objective measurement of pain is not given by pain scales. Pain is subjective, so someone else may be serious about what one person may classify as mild discomfort.

How do doctors use pain scales?

Any type of pain scale can be used by physicians to determine how pain affects someone. When deciding which scale to use, medical practitioners may consider:

  • The patient’s age or literacy level: Children and people with low literacy levels can find it easier to rate their pain using purely visual scales. Healthcare professionals may prefer to use a numerical or verbal rating scale when assessing pain levels in adults.
  • Cognitive ability: Similarly, people with cognitive impairments may find it easier to use a faces scale. Facial expressions can be easier for people to understand if they are in shock following an injury, taking strong pain medication, or have difficulty speaking.
  • Their field or specialism: Some pain scales may be more useful than others depending on a doctor’s specialism. For example, someone working in an emergency department may prefer to use unidimensional scales, as they provide faster results. However, an oncologist may choose a multidimensional scale, so they can fully understand how cancer affects a person’s life.

How individuals respond to a pain scale or questionnaire may affect their treatment.

Pain scales with facial expressions

Pain scales with facial expressions
Design credit: Diego Sabogal

The most common choices for describing or rating pain are pain scales with facial expressions, such as the FPS-R and the Wong-Baker scale.

On a scale of 1-10, the FPS-R grades pain, with 0 reflecting “no pain” and 10 “very much pain.” Each level accompanies a facial expression, varying from content to distress.

The Wong-Baker scale, with certain variations in facial expressions and language, is very similar to the FPS-R. Here, 0 is “no hurt,” and 10 is “hurts worst,” reflecting the worst-ever pain for someone. This final face illustrates crying.

For individuals, facial pain scales are easy to understand. They are also used by doctors to assess children, though they can also be helpful if there is a language barrier. They may have some limitations, however.

The facial expressions of these pain scales show how much pain an person feels internally, rather than how their face looks externally. For kids, who can interpret the expressions as thoughts, such as being happy or sad, this can be confusing.

Unidimensional scales

Numerical rating scale

Unidimensional scales
Design credit: Diego Sabogal

In general, a numerical rating scale involves a horizontal line labelled with the numbers 0-10. People point to or claim the number that best describes the pain level they feel.

A 2018 study shows that the numerical rating scale is easy to use for adults with no cognitive impairment. It also lets individuals with less than 10 levels of pain be more precise than scales. As it is easy to measure, researchers also use numerical pain scales to collect information.

A more visual scale, however, may be preferred by people from certain cultures. For instance, a 2018 study found that the FPS-R was preferred by Nepalese adults, and an analysis from the same year states that Swahili-speaking individuals also preferred a faces scale in studies.

Visual analog scale

Visual analog scale
Design credit: Diego Sabogal

In appearance, visual analog scales can vary. Some are simple lines with at one end “no pain” and at the other “serious pain”. To show how much pain they are feeling, people mark a point between those extremes.

One of the advantages of visual analog scales is that individuals may express their precise level of pain. For individuals that have long-term conditions and pain levels that differ over time, this can be helpful.

For researchers, visual analog scales are more sensitive instruments, and less prone to bias. According to a 2017 paper, studies suggest they are reliable and accurate.

It can be hard for individuals, however, to rate their pain without labels or descriptors on these scales, particularly if they have cognitive impairments. Healthcare professionals may also struggle to interpret the results.

Verbal rating scale

Verbal rating scale
Design credit: Diego Sabogal

With verbal rating scales, people verbally describe their pain on a scale from “mild” to “severe.” Numerous studies indicate that, while offering reliable information, individuals find these scales easy to understand and use.

In contrast to visual analog scales, however, verbal rating scales are less sensitive. They may also contribute to miscommunication and can create a barrier to language for individuals who do not speak the language of their doctor. Some can find numerical scales easier to use and interpret in these cases.

Multidimensional scales

Brief pain inventory scale

The brief pain inventory (BPI) scale is a short questionnaire fill out by individuals so that healthcare providers can measure the pain of a person and how it affects them.

The BPI scale measures the severity of pain, the location of pain, how much pain interferes with everyday life, and how much pain within a given time frame a person experiences. In several languages, it is accessible and includes illustrations to help anyone describe where their pain is.

As well as pain medication, the BPI scale also looks at how long pain lasts. It does take more time than a simpler pain scale to complete, however.

McGill Questionnaire on pain

Another questionnaire that individuals fill out by themselves to assess their discomfort is the McGill pain questionnaire (MPQ). In 17 different la this pain scale is available.

The MPQ measures how pain feels physically, in addition to pain intensity, allowing individuals to identify symptoms such as burning or throbbing. It also looks at how this affects someone emotionally. For measuring pain from long-lasting conditions, this can be beneficial.

However, the variety of ways of describing pain with an MPQ can be a drawback, as it requires an understanding of its vocabulary. For children or adults who do not understand language, such as “smarting,” it is not suitable.

In addition, it takes longer to complete the MPQ than other techniques of measuring pain, making it less convenient.

When to see a doctor

If they encounter any discomfort that is serious or interrupts everyday tasks, people should see a doctor or other healthcare professional. Call 911 or a local emergency department for pain that is sudden and intense.

Summary

Pain scales are instruments for describing the pain endured by a person. In order to evaluate people and decide about the appropriate course of action, healthcare professionals use them.

There are many types of pain scale. Some are fast and easy to use, but less reliable. Others are more detailed, but for some it may be more difficult to comprehend. A facial pain scale, which includes facial expressions, could be easier for children to use.

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