Pain scale types: Benefits and limitations

A pain scale is a chart that represents different levels of pain, from mild to severe. People can use pain scales to help them describe how much pain they are feeling.

There are many pain scales, but healthcare professionals and researchers often use one of four main types:

• 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, which means people can use either words or images to describe their pain. Multidimensional pain scales tend to be more in-depth and take longer to use.

It is important to note that pain scales do not provide an objective measurement of pain. Pain is subjective, so what one person may class as mild discomfort may be severe to someone else.

Doctors can use any pain scale type to assess how pain affects someone. When deciding which scale to use, healthcare professionals 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 people respond to a pain scale or questionnaire can influence their treatment.

 

Pain scales with facial expressions, such as the FPS–R and the Wong-Baker scale, are among the most popular options for describing or rating pain.

The FPS–R rates pain on a scale from 1–10, with 0 representing “no pain” and 10 “very much pain.” Each level accompanies a facial expression, ranging from content to distressed.

The Wong-Baker scale is very similar to the FPS–R, with some differences in the facial expressions and language. Here, 0 represents “no hurt,” and 10 indicates “hurts worst,” representing someone’s worst-ever pain. This final face illustrates crying.

Faces pain scales are easy for people to understand. Doctors often use them to assess children, while they can also be useful if there is a language barrier. However, they do have some limitations.

These pain scales’ facial expressions represent how much pain a person feels internally, rather than how their face looks externally. This can be confusing for children, who may interpret the expressions as emotions, such as being happy or sad.

Numerical rating scale

A numerical rating scale usually includes a horizontal line marked with the numbers 0–10. People point to or say the number that best represents the level of pain they are feeling.

A 2018 review suggests that adults with no cognitive impairments find the numerical rating scale easy to use. It also lets people be more specific than scales with fewer than 10 pain levels. Researchers often use numerical pain scales to gather data, as it is easy to interpret.

However, people from some cultures may prefer a more visual scale. For example, a 2018 study found that Nepalese adults preferred the FPS–R, and a review from the same year notes that Swahili-speaking people also preferred a faces scale in studies.

Visual analog scale

Visual analog scales can vary in appearance. Some are simple lines with “no pain” at one end and “severe pain” at the other. People mark a point between those extremes to demonstrate how much pain they are experiencing.

One of the benefits of visual analog scales is that people can express their precise pain level. This can be useful for people who have long-term conditions with pain levels that vary over time.

Visual analog scales are more sensitive tools for researchers, and less prone to bias. According to a 2017 paper, studies suggest they are reliable and accurate.

However, it can be difficult for people to rate their pain on these scales without labels or descriptors, particularly if they have cognitive impairments. Healthcare professionals may also struggle to interpret the results.

Verbal rating scale

 

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

However, verbal rating scales are less sensitive compared to visual analog scales. They can also lead to miscommunication and may present a language barrier for people who do not speak their doctor’s language. In these cases, some may find numerical scales easier to use and interpret.

Brief pain inventory scale

The brief pain inventory (BPI) scale is a short questionnaire that people fill out so healthcare professionals can assess a person’s pain, and how it impacts them.

The BPI scale measures pain intensity, pain location, how much the pain interferes with daily life, and how much pain a person experiences within a certain time frame. It is available in many languages and contains pictures to help someone describe where their pain is.

The BPI scale also looks at how long pain lasts, as well as pain medication. However, it does take more time to complete than a simpler pain scale.

McGill pain questionnaire

The McGill pain questionnaire (MPQ) is another questionnaire that people fill out by themselves to measure their pain. This pain scale is available in 17 different languages.

In addition to pain severity, the MPQ measures how pain feels physically, allowing people to describe sensations such as burning or throbbing. It also looks at how this affects someone emotionally. This can be useful for assessing pain from long-lasting conditions.

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

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

People should see a doctor or other healthcare professional if they experience any pain that is severe or interrupts daily activities. For pain that is sudden and severe, call 911 or a local emergency department.

Pain scales are tools to describe the pain that a person experiences. Healthcare professionals use them to assess people and decide on the best course of treatment.

There are many types of pain scale. Some are easy and quick to use, but less precise. Others are more detailed but can be more difficult for some to understand. Children may find it easiest to use a faces pain scale, which includes facial expressions.