Visual analogue scales (VAS) of sensory intensity and affective magnitude were validated as ratio scale measures for both chronic and experimental pain. Chronic pain patients and healthy volunteers made VAS sensory and affective responses to 6 noxious thermal stimuli (43, 45, 47, 48, 49 and 51 degrees C) applied for 5 sec to the forearm by a contact thermode. Sensory VAS and affective VAS responses to these temperatures yielded power functions with exponents 2.1 and 3.8, respectively; these functions were similar for pain patients and for volunteers. The power functions were predictive of estimated ratios of sensation or affect produced by pairs of standard temperatures (e.g. 47 and 49 degrees C), thereby providing direct evidence for ratio scaling properties of VAS. Vas sensory intensity responses to experimental pain, VAS sensory intensity responses to different levels of chronic pain, and direct temperature (experimental pain) matches to 3 levels of chronic pain were all internally consistent, thereby demonstrating the valid use of VAS for the measurement of and comparison between chronic pain and experimental heat pain.

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The validation of visual analogue scales as ratio scale measures for chronic and experimental pain

The measurement of subjective pain intensity continues to be important to both researchers and clinicians. Although several scales are currently used to assess the intensity construct, it remains unclear which of these provides the most precise, replicable, and predictively valid measure. Five criteria for judging intensity scales have been considered in previous research: ease of administration of scoring; relative rates of incorrect responding; sensitivity as defined by the number of available response categories; sensitivity as defined by statistical power; and the magnitude of the relationship between each scale and a linear combination of pain intensity indices. In order to judge commonly used pain intensity measures, 75 chronic pain patients were asked to rate 4 kinds of pain (present, least, most, and average) using 6 scales. The utility and validity of the scales was judged using the criteria listed above. The results indicate that, for the present sample, the scales yield similar results in terms of the number of subjects who respond correctly to them and their predictive validity. However, when considering the remaining 3 criteria, the 101-point numerical rating scale appears to be the most practical index.

The measurement of clinical pain intensity: a comparison of six methods.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/acr.20543

Measures of Adult Pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP)

Of the different types of visual analogue and graphic rating scales tested in a series of experiments, only two were satisfactory: these were the visual analogue scale and the graphic rating scales used horizontally with the words spread out along the whole length of the line. Other types of scale used gave distributions of results which were not uniform. Unusual distribution of results occurred when patients selected a position adjacent either to descriptive terms or preferred numbers. In some experiments, the distribution of results was determined by the nature of the experiment. Alternation of the ends of a scale did not affect the results. The behaviour of the graphic rating scale was different in patients accustomed to completing it and in those not so accustomed. The results of pain severity measured by these methods showed a very good correlation with pain severity measured by the simple descriptive pain scale. Changes in visual analogue scores also correlated well with changes in simple descriptive pain scores. The visual analogue and graphic rating scales were more sensitive than the traditional simple descriptive pain scale. Most patients could readily use visual analogue and graphic rating scales despite having no previous experience. The failure rate was slightly lower with the graphic rating method. Use of these scales is the best available method for measuring pain or pain relief.

Graphic representation of pain.

Visual Analogue Scales (VAS) provide a simple technique for measuring subjective experience. They have been established as valid and reliable in a range of clinical and research applications, although there is also evidence of increased error and decreased sensitivity when used with some subject groups. Decisions concerned with the choice of scoring interval, experimental design, and statistical analysis for VAS have in some instances been based on convention, assumption and convenience, highlighting the need for more comprehensive assessment of individual scales if this versatile and sensitive measurement technique is to be used to full advantage.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033291700009934

Clinical applications of visual analogue scales: a critical review.

Measurement of pain.

Of the various methods for measuring pain the visual analogue scale seems to be the most sensitive. For assessing response to treatment a pain-relief scale has advantages over a pain scale. Pain cannot be said to have been relieved unless pain or pain relief has been directly measured.

E. C. Huskisson

Papers

Measurement of pain.

Measurement of pain.

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