The Visual Analog Scale (VAS) is a linear scale that measures the magnitude of pain severity (Fig. 3.1). It is designed for patients >8 years old. It encompasses a horizontal line scaled as a spectrum from mild pain beginning from the left to increasing severity to the right end of the horizontal line.² The line is commonly 10 cm in length, with each side of the line ending in extremes—either no pain or intense pain. Of note, the line may be present as a horizontal or vertical line.¹ In terms of utilization, the patient marks his or her pain on the line of the spectrum of the scale.³

The results of a majority of studies imply that there is little difference among pain scales; however, VAS has been demonstrated to be superior compared to the Numerical Rating Scale (NRS) or Verbal Rating Scale (VRS).¹ VAS has shown to be associated with different behaviors of pain and ratio-level scoring.¹ Furthermore, VAS has been demonstrated to be sensitive to treatment modalities.¹ It has also been noted that through VAS, pain severity assessed at two separate time points displays an accurate difference in magnitude of pain.³

There are other versions of the VAS. One such version is known as the mechanical VAS, which utilizes a marker that is slidable and is “superimposed” on the horizontal line. This horizontal VAS is described as being drawn on a ruler and can be scored based on the back, which has numbers for the scale.¹ Prior studies have revealed that the mechanical VAS has promising test-retest reliability.³

The VAS does have its own disadvantages. First it is difficult to apply the VAS to individuals who are experiencing perceptual-motor difficulties.¹ This is present in patients
experiencing chronic pain. Second, individuals commonly utilize a ruler as measuring pain intensity must account for centimeters or millimeters to assess their pain magnitude.¹ This can be time-consuming with the chance of introducing bias into the scale. Additionally, patients suffering from a cognitive disability may increase rates of incompletion.¹

The Visual Analog Scale has been used to measure pain in adults. The Visual Analog Scale has above-average noncompletion events with elderly patients.¹ Prior studies attribute failure rates among older populations toward three major categories: extent of motor abilities, level of impairment of cognitive ability, and level of education.⁴ The VAS does indeed require the conceptual thought of pain and the ability to move a pencil marking toward the area representing their appropriate level of pain.⁴ In the elderly population, it is recommended that VRS be utilized instead of VAS as prior studies have shown it has fewer failure responses.¹

The NRS allows the measurement of pain by having the user circle numbers (Fig. 3.2). These numbers can vary and range from 0 to 10, 0 to 20, or 0 to 100. The extremes of each scale
include 0 meaning a state of no pain and with the highest number correlating with a high pain intensity state.³ The NRS is akin to the VRS in that it has positive data supporting its validity. Past studies have shown that NRS corresponds well with measuring treatments for pain. This scale can be given as a written scale or orally. Positive benefits to this scale are that it is well understood, is not difficult to use, and can be scored with ease.¹ Patients who suffer from multiple pain symptoms appear to prefer NRS.²

The disadvantages of this test are that it lacks ratio qualities compared to VAS or Graphic Rating Scale (GRS).³ An example of this is cited by Lazaridou et al. in that equal intervals on the NRS may possibly not reflect the intensity of the pain.¹ This means that the interval distance between 9 and 7 may not be equivalent to the interval distance of 3 and 1.¹ Another disadvantage is “anchoring,” entailing that patients may sometimes “anchor” their pain at the higher limit of the scale, which can change the way they rate their pain intensities.¹

The VRS measures pain through a spectrum of adjectives (Fig. 3.3). These adjectives are listed from the least intensity of pain to the most severe intensity of pain.³ Those taking the test are requested to choose the appropriate adjective that accurately represents their pain.¹ Each adjective is associated with a scoring system.¹ Furthermore, the VRS is not just limited
by adjectives. Other forms of VRS encompass the use of phrases and a behavioral rating scale where the patient can describe their pain intensity by sentences.¹,³

The Verbal Rating Scale has many advantages. First, it is simple to use and is easy to administer and score. Second, the validity of VRS to measure pain is supported.¹ Third, compliance rates are positive and are reportedly due to the fact that it is not difficult to comprehend.¹ This can be applied to the elderly population. The results of the VRS correlate well with different types of pain measuring tools.¹ Verbal Rating Scale is analogs to VAS in this sense.³

The Verbal Rating Scale does have some disadvantages. The VRS may not have an appropriate number of responses to choose from as patients may run into difficulty in choosing the most accurate response to represent their pain.³ Additionally, accuracy of the test can be compromised as intervals between each word on the scale may not be weighted differently from the perspective of the patient. This can lead to difficulties in accurately rating pain intensity and changes in pain.³ Another limitation of the VRS is that in order for this test to work, the patient must know and understand the words given by this pain assessment.¹

The McGill Pain Questionnaire (MPQ) measures pain through several aspects and is considered comprehensive. It tests patients’ pain based on three aspects: cognitive-evaluative, affective, and sensory. This questionnaire comprises a list of 78 words that can be divided into 20 sections.¹ Each section consists of descriptors that are arranged from least intense to most intense. The sections are numbered based on the three aspects mentioned previously. For example, sections 1-10 are for sensory. Sections 11 through 15 represent the affective component.¹ Sections 16 is the evaluative arm of the questionnaire.¹ Sections 17 through 20 are the miscellaneous aspects of pain. Patients are asked to choose the words that best correlate with their pain severity.¹ Once chosen, the selected words are translated to a pain index. The words chosen by the patients are summed and assigned a ranking.¹ The MPQ also includes measuring the present pain severity based on an intensity scale of 1 to 5.²

A shorter version of the MPQ is also utilized in clinical practice. This involves 15 words or descriptors that belong to the sensory and affective category. The sensory category is composed of 11 descriptors, and the affective category consists of 4 descriptors. They are rated on a magnitude scale from 0 to 3—0 being “none” to 3 being the most “severe” experience of pain.¹,²

The short MPQ has reportedly been comparable to the original MPQ.² The short MPQ may be easier to use compared to the original MPQ as it is shorter to administer.² This version of the MPQ is beneficial for obstetrics and surgical patients.² The short MPQ has shown to be sensitive enough to show differences due to treatments.² Lastly, this version may be easier for geriatric patients.¹

The Brief Pain Inventory (BPI) was created to evaluate patients with cancer. However, as time progressed, this assessment tool began to be utilized for generic/chronic pain patients. It is available in a long and short version. The long version includes 17 items, and the short version encompasses 9 items⁵ (Fig. 3.4).

The long form required a longer period of 1 week to gauge pain interference and severity. This version inquired use of medications and to evaluate for descriptors that may accurately report their pain.⁶ Questions from the long version included techniques to mitigate pain and
associated length and percentage of pain relief.⁶ Because this version was found to take too long, especially if used repeatedly, the shorter version was produced.⁶

The shorter version is more common and will be described as follows.⁵ This version of the BPI assesses pain through two major categories. The first category is by pain score severity, and the second category is the pain interference score.⁵ The pain severity score draws from the four options describing pain severity. This includes current pain, average pain, least pain, and worst pain. Each of these options is then rated with a score of 0, meaning without pain, or to a high score of 10, which means the most severe pain.⁵ The total possible score can be from
either 0 to the max score of 40.⁵ The pain interference portion of the inventory is designed through seven categories. These categories include work, general activity, mood activity, ability to walk, relationships, enjoyment of life, and sleep.⁶ These categories are assigned a value of 0, meaning no interference, or 10, meaning interferes completely. The total score can be from 0 to 70 on this inventory.⁵

The Neonatal Infant Pain Scale (NIPS) is a pain assessment tool that is often used and has been shown to be dependable with high validity¹,² (Table 3.1). This test includes detecting
and measuring behaviors of pain. This includes arousal state, arm movement, breathing, leg movement, facial expression, and crying.¹ Each category consists of its own subcategories. For example, the facial expression category includes relaxed with a score of 0 and grimace with a score of 1.² The category for “cry” consists of “no cry” with a score of 0 to “vigorous” with a score of 2.² The NIPS can range from 0 to 7. A summation score of >3 is an indicator for the presence of pain.²