Do Commonly Used Measures of Pain Intensity Only Reflect Pain Intensity in Youths With Bothersome Pain and a Physical Disability?

The objective of this cross-sectional study was to evaluate the extent to which non-pain intensity factors influence the ratings of pain intensity on two commonly used measures: the Wong-Baker Faces pain rating scale (FACES) and the Verbal Rating Scale (VRS) in a sample of youths with physical disabilities and bothersome pain. Study participants came from a convenience sample of 115 youths (age: X ¯ = 14.4 years; SD = 3.3), who participated in a survey on the impact of pain in young people with a physical disability. They were administered measures of pain intensity, pain catastrophizing, depressive symptoms, pain interference, and pain control beliefs. Zero-order correlation analyses were used to examine the associations among the pain intensity scores, while regression analyses were used to test the influence of the non-pain intensity factors on the pain intensity scores. Although pain intensity scores from all scales were significantly associated with one another, the correlations were moderate. Regression analyses showed that the FACES and VRS also reflect pain interference, in addition to pain intensity. The fact that the FACES and VRS ratings reflect more than pain intensity should be considered when selecting a pain measure. The results of this study also provide information to help interpret results after treatment.

The validity of pain intensity measures: what do the NRS, VAS, VRS, and FPS-R measure?

BACKGROUND AND AIMS: The Numerical Rating Scale (NRS), Visual Analogue Scale (VAS), Verbal Rating Scale (VRS), and Faces Pain Scale-Revised (FPS-R) are valid measures of pain intensity. However, ratings on these measures may be influenced by factors other than pain intensity. The purpose of this study was to evaluate the influence of non-pain intensity factors on the pain intensity scales. METHODS: We administered measures of pain intensity (NRS, VAS, VRS, FPS-R), pain unpleasantness, catastrophizing, depressive symptoms, and pain interference to 101 individuals with chronic lower back or knee pain. Correlation analyses examined the associations among the pain intensity scales, and regression analyses evaluated the contributions of the non-pain intensity factors (depressive symptoms, and pain unpleasantness, catastrophizing, and interference) to the VAS, VRS, and FPS-R ratings, while controlling for NRS, age, and gender. RESULTS: Although the NRS, VAS, VRS, FPR-S, scales were strongly associated with one another, supporting their validity as measures of pain intensity, regression analyses showed that the VRS also reflected pain interference, the FPS-R also reflected pain unpleasantness, and the VAS was not associated with any of the additional non-pain intensity factors when controlling for NRS, age, and gender. CONCLUSIONS: The VAS appears to be most similar to the NRS and less influenced by non-pain intensity factors than the VRS or FPS-R. Although the VRS and FPS-R ratings both reflect pain intensity, they also contain additional information about pain interference and pain unpleasantness, respectively. These findings should be kept in mind when selecting pain measures and interpreting the results of research studies using these scales. IMPLICATIONS: The influence of pain interference and pain unpleasantness on VRS and FPS-R, respectively should be kept in mind when selecting pain measures and interpreting the results of research studies using these scales.

The buffering role of positive affect on the association between pain intensity and pain related outcomes.

OBJECTIVES: Chronic pain is a significant problem worldwide and is associated with significant elevations in negative affect, depressive symptoms, sleep problems, and physical dysfunction. Positive affect could potentially buffer the impact of pain on patient functioning. If it does, then positive affect could be directly targeted in treatment to benefit individuals with chronic pain. The purpose of this study was to test for such moderating effects. METHODS: This was a cross-sectional study, we administered measures of pain intensity, depressive symptoms, sleep problems, pain interference, and positive and negative affect to 100 individuals with chronic back or knee pain in a single face-to-face assessment session. RESULTS: The associations between pain intensity and negative affect, and between pain intensity and depressive symptoms were moderated by positive affect. This moderation effect was explained by the fact that participants with low positive affect evidenced strong associations between pain intensity and both depression and negative affect; participants with high positive affect, on the other hand, evidenced weak and non-significant associations between pain intensity and both depression and negative affect. Positive affect did not moderate the associations between pain intensity and either sleep problems or pain interference. CONCLUSION: The findings are consistent with the possibility that positive affect may buffer the impact of pain intensity on negative affect and depressive symptoms. Longitudinal and experimental research is needed to determine the potential benefits of treatments that increase positive affect on negative affect and depressive symptoms in chronic pain populations. IMPLICATIONS: The study findings suggest the possibility that "positive psychology" interventions which increase positive affect could benefit individuals with chronic pain by reducing the impact of pain on negative outcomes. Research to test this possibility is warranted.

A Comparison of Pain Beliefs and Coping Strategies and Their Association with Chronic Pain Adjustment Between Singapore and United States.

OBJECTIVES: Research examining the importance of pain beliefs and coping strategies to chronic pain adjustment has been performed almost exclusively using Western populations. The purpose of this study was to examine empirically the generalizability of this research to Singapore. METHODS: Employing a cross-sectional design, measures assessing pain beliefs, coping strategies, pain intensity, pain interference, and depressive symptoms were administered to 101 patients with chronic pain from Singapore. Analyses examined the means of belief and coping strategies measures and their associations with measures of pain intensity, pain interference, and depressive symptoms and compared the results with the data of a sample of 100 patients with chronic pain from a previously published study from the United States. RESULTS: Mean differences between the Singapore and US samples were found for four of the seven belief scales, and four of the eight coping scales. When significant, associations between belief and coping strategies with measures of pain and dysfunction were in the hypothesized directions in both samples. We also found that the strength of four out of 30 of the associations between beliefs/coping strategies and measures of pain and dysfunction were different between the Singapore and US samples. CONCLUSION: The findings provide further support for the potential influence of culture on how individuals view and cope with pain. However, the many similarities found in direction and strength of the associations between beliefs/coping strategies and measures of pain/dysfunction provide preliminary support for the appropriateness of the use of cognitive behavioral therapy developed in the United States with the Singapore population.