10 Distinct Varieties of Pain Scales and How They Gauge Levels of Distress
The experience of pain is an intensely individual and subjective phenomenon. It is a universal sensation, a physical discomfort that arises from illness or injury, and often serves as the first warning that something is amiss within the body. However, pain can manifest in a multitude of ways, with varying levels of intensity depending on the extent of the injury sustained or the gravity of the condition. These pain levels can range from mild sensations that are more bothersome than agonizing to incapacitating pain that hinders mobility.
Pain also functions as the body's mechanism for signaling the need to cease certain physical activities that worsen the condition. For instance, the pain arising from a sudden ankle sprain becomes more pronounced each time the ankle is moved. The severity of the sprain directly correlates to the intensity of the pain signal. Furthermore, pain can also alert the body to take preventive action to avert further harm. For example, if a body part comes into contact with an open flame, even the slightest sense of pain triggers an immediate response to protect the body. In most cases, this reaction is instantaneous.
Significantly, pain acts as an indicator that something is awry and requires attention. These sensations can manifest as localized soreness in specific body parts (such as tired legs) or as a diffuse discomfort spread throughout the entire body (like fatigue). Additionally, there are transient bursts of pain, ranging from piercing sensations like stomach cramps to pulsating ones like headaches. Pain can also result from extreme experiences of temperature, such as burns or frostbite.
Acute and Chronic Pain
Recurring pain in the body might signify a chronic condition demanding urgent attention. In general, pain can be categorized as either acute or chronic. Acute pain is experienced for a short period, usually lasting between a few minutes to around three months.
Pain stemming from soft-tissue injuries or temporary illnesses is often considered acute since it lasts for a brief duration. It is commonly described as sharp or severe, and its duration can range from a few seconds to several hours.
On the other hand, pain that persists for more than three months, whether continuous or intermittent, is classified as chronic pain. This type of pain is typically a result of an ongoing illness (like cancer) or a chronic condition such as arthritis, scoliosis, or fibromyalgia. It is important to note that if acute pain is not appropriately addressed and treated in a timely manner, it can evolve into chronic pain.
Other Varieties of Pain
Aside from classifying pain as acute or chronic, it can also be categorized based on its origin. Pain can be identified as neuropathic, nociceptive, or radicular pain, and these categories can be further classified as acute or chronic pain.
Neuropathic pain is pain that arises from damage to the nervous system. It is often characterized by a sensation akin to being pricked by a multitude of tiny pins and needles simultaneously all over the affected area. Neuropathic pain also affects the sense of touch, making it challenging to discern hot or cold sensations.
Nociceptive pain is the pain felt when body tissue is injured, typically caused by external injuries. This type of pain is experienced in the joints, tendons, skin, muscles, and bones, and it can be either chronic or acute. Examples of nociceptive pain include head injuries, muscle sprains, and bone fractures.
Radicular pain is a distinct kind of pain caused by an inflamed or compressed spinal nerve. The pain is described as radiating, originating from the back or hips and traveling down the legs through the spine and spinal nerve root. When the pain radiates from the back into the leg, it is referred to as radiculopathy, commonly known as sciatica, as the sciatic nerve is often the source of the discomfort.
The Challenge of Describing Pain
Offering an accurate depiction of pain aids in narrowing down its source. Diagnosing the cause of pain often requires medical practitioners to ask patients to describe their pain. Common queries include identifying the location of the pain, whether it is continuous or intermittent, and whether it hinders the patient from performing regular activities. Most importantly, doctors and medical staff need to understand the intensity of the pain. Only then can they suggest suitable interventional pain treatment solutions.
This is where the challenge arises. Pain, as defined by the National Institute of Health, is a subjective experience. Requesting a patient to describe their pain, while also taking into account the observations of an observer, can be influenced by numerous factors. These factors may include socio-economic status, beliefs, and psychological state. For instance, the same injury may produce different responses depending on various circumstances. A person engrossed in a task or in a hurry to reach a destination may be more inclined to overlook an injury compared to others.
The subjectivity of pain impedes an accurate assessment of a patient's condition. What may be excruciatingly painful for one individual could be mildly painful for another, or vice versa. Moreover, as pain is a deeply personal experience, conveying it accurately can be challenging. At the same time, medical personnel tasked with recording this information may find it equally difficult to translate it into an objective report. Measuring the degree of pain is of utmost importance for both medical staff and patients, as it helps identify likely causes and facilitates the development of appropriate solutions.
How is Pain Measured?
Pain is subjective and largely dependent on how patients perceive it. While medical science has developed various methods to document patients' pain, there is still much to learn about pain due to its inherently subjective nature. However, throughout the centuries, attempts have been made to understand and quantify pain.
Schmerzpunkte: One of the earliest recorded endeavors to measure pain occurred in 19th-century Germany. The discipline of "psychophysics" explored the relationship between stimuli and sensation. Scientist Maximilian von Frey devised a method to measure what he called "Schmerzpunkte" (pain points). He used horsehairs of different stiffness attached to individual sticks and pressed these hairs against a subject's skin. Von Frey then documented the amount of pressure that could cause a person to feel pain from a specific hair. Furthermore, he and his colleagues in psychophysics also experimented with other methods to test skin sensitivity, including using hot or cold rods with varying temperatures.
Dolorimeter: Fast forward to the 1940s when a group of researchers sought to build upon the work of psychophysics. James Hardy, Helen Goodell, and Harold Wolff, all from Cornell University, developed a pain-measuring device known as the dolorimeter. They created this device to assess the effectiveness of analgesics. Dolorimeters apply constant heat, pressure, or electricity to a body area to determine patients' pain thresholds and tolerance levels. Their studies revealed that, on average, subjects reported experiencing pain at a skin temperature of 113 °F (45 °C). Additionally, they found that after reaching a threshold of 152 °F (67 °C), pain sensations did not intensify even with increased heat.
Based on the study's findings, the researchers established the "Hardy-Wolff-Goodell" scale, consisting of 10 levels called "dols." However, other research teams were unable to replicate their study, and the idea of dolorimeters was eventually abandoned. Nevertheless, their work did guide scientists in the right direction.
Modern Pain Scales
The Wong-Baker Faces Scale provides a visual representation of pain that even children can comprehend. With the advancement of modern science and an increasing awareness of medical ethics, the methods for measuring pain have become less intrusive, avoiding any harm to patients. Instead, patients are simply asked to describe their pain, and this information is then recorded and compared against established standards. While still subjective, this approach provides medical practitioners with more insights into the degree of pain experienced by their patients.
There are three fundamental categories of pain scales, which are distinguished based on the type of input data required for the assessment:
Numerical Rating Scales (NRS) use numbers to rate pain. Patients are typically asked to select a number from a given scale that best represents the intensity of their pain.
Visual Analog Scales (VAS) utilize a scale where patients mark the point that corresponds to their perceived pain levels.
Categorical Scales employ words to describe pain levels. These scales may incorporate numbers, colors, or relative positions to communicate pain intensity.
While numerical rating scales offer quantitative data and visual analog and categorical scales provide qualitative data, one type is not inherently superior to the others. Pain measurement often requires a combination of both quantitative and qualitative data to arrive at a more accurate diagnosis.
10 Pain Scales and How They Gauge Pain Levels
Numerical Rating Pain Scale: The Numerical Rating Pain Scale is a straightforward pain scale that categorizes pain levels from 0 (No pain) to 10 (Worst Pain Possible). This simple tool assumes a basic understanding of numbers and is suitable for patients over the age of nine.
Patients are asked to rate three types of pain: Current, Best, and Worst Pain experienced within the past 24 hours. Medical personnel calculate the average of the three ratings to determine the patient's current pain level.
Wong-Baker Faces Scale: The Wong-Baker Faces Scale features faces depicting various emotions, from Smiling (0, or no pain) to Crying (10, worst pain). Drs. Donna Wong and Connie Baker developed this tool, which simplifies the numerical rating of pain by assigning a graphic representation to each number on the pain scale.
The Wong-Baker Faces Scale was designed to help children convey their pain levels. It has been tested for use with patients aged 3 years and above. It is also suitable for illiterate patients or those with limited verbal abilities. Additionally, it provides a culturally-sensitive representation of facial expressions.
FLACC Scale: The FLACC (Face, Legs, Arms, Crying, Consolability) scale is a behavioral pain assessment tool used to gauge pain levels in nonverbal or preverbal patients who lack the means to communicate their own pain levels. Healthcare providers can assess patients' pain levels by observing the five FLACC categories and assigning scores (0, 1, or 2) that best describe the patient's condition. This scale is valuable for assessing infants and children between two months and 18 years of age, especially for those with cognitive impairments, developmental delays, or previous conditions.
COMFORT Scale: The COMFORT scale is a measurement tool employed by healthcare providers to assess pain levels in patients who are unable to self-report. This includes infants, children, incapacitated or cognitively impaired adults, and sedated or ICU-confined patients.
The COMFORT Scale provides a pain rating ranging from 1 (low) to 5 (high) based on nine categories:
Calmness / Agitation
Note that some versions of the COMFORT scale may have a different number of categories, and in some cases, certain categories are grouped together.
Visual Analogue Scale: The Visual Analogue Scale (VAS) is a tool used to measure pain as a continuous sensation without distinct jumps between levels like none, mild, moderate, and severe. The VAS was designed to align with patients' perception that their pain is a continuous experience, rather than a series of abrupt changes.
The simplest version of the VAS is a single 100 mm line ranging from "No Pain" to "Very Extreme Pain." Patients are asked to mark a point on the line that corresponds to their current pain level. The VAS score is then determined by measuring in millimeters from the left end to the mark. Other variations of the VAS, including vertical lines and lines with descriptors, have been developed.
McGill Pain Questionnaire: The McGill Pain Questionnaire consists of 78 adjectives that help patients describe their pain. Designed for literate patients, this questionnaire aids in developing a rehabilitation plan by pinpointing the range of pain experienced. Patients mark the words that closely match their pain levels, and medical staff assign a score (not exceeding 78) based on the number of marked words.
Defense and Veterans Pain Rating Scale (DVPRS): Pain assessment in a battlefield setting often necessitates a specialized pain scale. As a result, the Department of Defense developed the DVPRS. The DVPRS is a relatively recent scale that combines the Wong-Baker pain scale of 0-10 with an assessment tool that evaluates the impact of pain on patients' daily functioning. Additionally, the DVPRS includes supplementary questions that help determine the effects of pain on various aspects of a patient's daily life, such as activity, sleep, mood, and stress.
Pain Assessment in People With Dementia (PAINAD): Many older adults, especially those with dementia, lose the ability to communicate clearly. For comprehensive pain specialists, determining their pain levels using conventional scales can be challenging. The PAINAD scale was designed specifically to assess pain in dementia patients based on five specific indicators: breathing, vocalization, facial expression, body language, and consolability. Similar to FLACC, each category contains three choices ranging from 0 to 2. A trained healthcare professional can use the PAINAD scale to assess patients within five minutes of observation.
Behavioral Pain Scale (BPS): As sedated, intubated, or ventilated patients are unable to respond to detailed questioning, the Behavioral Pain Scale is used to make visual assessments. The Behavioral Pain Scale is a simplified version of the McGill Pain Questionnaire and aids in assessing pain levels in sedated or mechanically ventilated critically ill patients. This scale works well for patients who cannot communicate due to their current medical condition. BPS comprises three items: Facial Expression, Upper Limbs, and Compliance with Ventilation, each with four distinct choices. Healthcare providers need only select the value that best matches the patient's current behavior.
Mankoski Pain Scale: The Mankoski Pain Scale, created by Andrea Mankoski in 1995, is a popular pain scale that defines well-defined pain states. Designed for conscious patients with moderate literacy skills, this scale provides a more detailed assessment of pain levels. Patients simply choose a number between 0 (Pain-free) to 10 (Unconscious) to describe their current pain state. Mankoski graciously made this pain scale available to the public for free, as long as proper attribution to the author is given. The Mankoski Pain Scale categories are as follows:
0 – Pain-free
1 – Very minor annoyance – occasional minor twinges. No medication needed.
2 – Minor Annoyance – occasional strong twinges. No medication needed.
3 – Annoying enough to be distracting. Mild painkillers take care of it. (Aspirin, Ibuprofen.)
4 – Can be ignored if you are really involved in your work, but still distracting. Mild painkillers remove pain for 3-4 hours.
5 – Can't be ignored for more than 30 minutes. Mild painkillers ameliorate pain for 3-4 hours.
6 – Can't be ignored for any length of time, but you can still go to work and participate in social activities. Stronger painkillers (Codeine, narcotics) reduce pain for 3-4 hours.
7 – Makes it difficult to concentrate, interferes with sleep. You can still function with effort. Stronger painkillers are only partially effective.
8 – Physical activity severely limited. You can read and converse with effort. Nausea and dizziness set in as factors of pain.
9 – Unable to speak. Crying out or moaning uncontrollably – near delirium.
10 – Unconscious. Pain makes you pass out.
Pain scales play a crucial role in the medical assessment and treatment of patients experiencing pain. Despite the subjectivity of pain, these scales provide valuable information to healthcare providers in understanding and addressing their patients' needs. From the ancient Schmerzpunkte to modern pain scales like the Wong-Baker Faces Scale and Numerical Rating Pain Scale, each method offers unique insights into the complexities of pain perception. As medical science continues to advance, the quest to comprehensively measure pain and tailor effective pain management solutions remains an ongoing and essential pursuit.